Nikon Camera and Lens Information and Repair

Version 2.03o (2-Feb-26)

Copyright © 1994-2026
Samuel M. Goldwasser
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Table of Contents

Repairing Broken SWM Gear Shaft in Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G VR II Zoom Lens

This is the gear between the SWM itself and the Focus Gear that engages the drive gear on the Focus Ring. The shaft is part of the Fixed Barrel and thus made of the same plastic as the structure. While it isn't likely to break during normal use, it can get stressed when going inside to repair something else, particularly during the removal or replacement of the Fixed Shell.

If it fractured at its base, the original shaft can be reused but if it fractured in the middle, a substitute shaft will be required which can be made of metal. Note that the original shaft is NOT a constant diameter but is thinner at the top. It is not known whether this is essential if a replacement shaft is used. It probably allows for a larger tolerance in the positioning of the metal fork of the Autofocus A/M switch.

Either way, a hole will need to be drilled perfectly centered and square in the Fixed Barrel so that a replacement shaft can be installed. The diameter at the base is approximately 0.045 inches but this should be confirmed. Ideally it will be a press-fit without requiring adhesive.

  1. Refer to the instructions in the section: Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G VR II Zoom Lens Disassembly and follow them to the step where the Fixed Shell is removed along with the SWM and Focus Gears.

  2. Arrange for any protruding cables to be well away from the area of the SWM Gear shaft.

  3. Using a drill press and 0.040" bit, very carefully drill a hole to a depth of around 3/32".

  4. Test to see if the broken or replacement shaft will fit the hole. If close, it can be widened with the tip of a needle file or a slightly larger drill bit. But avoid going oversize.

  5. Once the replacement shaft just barely fits in the hole, it can be gently pressed into place. Using a bit of non-softening plastic adhesive may be worthwhile.

  6. Check the fit and then following the reassembly instructions.

A Tail of Two Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G VR II Zoom Lenses

These were purchased as "For Parts or Not Working" on eBay and are IDs #9 and #10, above. ID #9 would attempt to focus with some hunting but usually would give up. Sometimes it signaled focus lock but even then it would often not be anywhere near the correct focus. VR appeared to work. ID #10 was not recognized by the camera at all.

So the plan was to see what would happen if the main PCB from ID #9 was swapped into ID #10. Accessing the main PCBs in these lenses is relatively straightforward. The only annoyances are (1) there is a soldered ground wire and (2) the flex-cable for the gyros is nestled under the PCB and a bit of a pain to get at. But other than those, it's just screws and flex-cables. The transplant was performed without incident. Autofocus appeared to work flawlessly but there was a horizontal "jump" to one side and back in the image in the viewfinder when the camera was powered on indicating an issue with VR. In fact VR appears to be dead after the jump. This probably means it is unable to initialize. It may be that the horizontal gyro is defective or that the aforementioned cable wasn't installed properly (though I rather doubt that). In the end, it was decided to simply unplug the flex-cable for the VR actuator and live with no VR on this lens. That's probably a fair trade. It's also not known how closely matched VR is to the specific lens, so even it VR did work, it might not be optimal. Another observation for lens ID #10 was that one of the metal shims between the plastic ring and lens body was corroded indicating possible water damager, though everything else including the optics appear pristine.

I was expecting that a swap of the PCB from ID #10 into ID #9 would result in a lens that is not recognized.

But before then I decided to check for continuity from the camera contact strip to the PCB and discovered that there was an open circuit to the contact at one end. Indeed, the flex-cable is tearing where it passes the edge of the PCB. So I figured I would swap it with a flex-cable from the VR II lens in the dissection which was thought to also have a dead PCB. But that flex-cable, too, is torn. So this must be a common problem. Whether it is caused by rough handling during disassembly or reassembly, or a design flaw is not known. Now I need at least 2 good flex cables for the 18-55mm VR II lens. ;-)

Replacing Torn Camera Contacts Ribbon Cable in Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G VR II Zoom Lens

This was first done on AF-S 18-55mm VRII lens #11, which originally had a very cockeyed front zoom barrel. That was corrected with some rather un-gentle persuasion and mechanically. The lens appears fine with perhaps just a bit of stiffness over a portion of the zoom range, though probably nothing beyond normal sample-to-sample variation. But the lens was not recognized by the camera. At that point I was sorry I didn't check it before correcting the mechanical issue suspecting that perhaps the "repair" was at fault. However, upon initial interior inspection, it was found that the Camera Contacts Flex Cable was torn cleanly in half. This may have been caused by the previous owner's attempts to repair it though - it could not have been by the trauma or its remedy.

A crack or even clean break at the crook of the elbow of this ribbon cable appears to be relatively common with these lenses. So common in fact that replacement cables are readily available on eBay, even in two-packs.

With a bit of care, replacement is straightforward. It is among the simplest of the "in-lens" repairs:

  1. Remove the two screws securing the Camera Contacts Assembly.

    Remove the three screws securing the Trim Ring and take it off.

  2. Set zoom to the 55 mm position. This retracts the rear lens assembly forward so it is out of the way.

  3. If the cable is totally torn, the Camera Contacts Assembly can be removed. And there is no practical way to repair a slightly torn cable even if just a single conductor is severed, so feel free to complete the tear. ;-) However, keeping whatever is left of the cable intact will provide a feel for minimizing stress on it during reassembly.

  4. Remove the three screws securing the Bayonet Mount Ring to the body of the lens. Lift it straight out along with the metal and plastic spacers. Keep them together so their relative orientation won't be lost. Note location of the spring ground contact pin poking up from the main lens assembly and where it goes in the Bayonet Mount Ring and spacers.

  5. Carefully pull off the three small ribbon cables. There are convenient holes in the tabs that may be used. Avoid scratching anything underneath.

  6. Remove the two screws securing the Main PCB.

  7. Lift the Main PCB with the long ribbon cable so it detaches from the socket inside the lens. This may be easier than attempting to pull it off side-ways.

  8. Carefully flip the Main PCB over without detaching the soldered ground wire.

  9. Pull off the remains of the Camera Contacts Ribbon Cable tab. There may be some adhesive to keep the middle portion from moving around.

To prepare the replacement:

  1. The mating portion of the Camera Contacts Ribbon Cable Assembly has a series of eight gold-plated pads held against the actual metal contacts with a metal locking strip.

  2. With the Camera Contacts facing down, slide the metal strip off to release the ribbon cable. If this is done carefully, the metal contacts won't fly all over the place.

  3. Remove the remains of the old ribbon cable from the locking strip.

  4. Peel off the paper protecting the adhesive over the new ribbon cable and then stick on the locking strip taking care that it is in the same orientation and position.

  5. Slide the locking strip with cable back under the tabs securing it.

Reassembly of the lens is now just the reverse of disassembly. Zoom should remain set to 55 mm. Take particular care not to stress the flex cable during the process. Or else you'll be doing this all over again. :( ;-)

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens

I have not found a repair manual or even an exploded diagram for this lens. If anyone has one, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Description

The following applies directly to the Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens and probably mostly to the non-VR version as well.

The AF-P lens is optically very similar to the AF-S versions, above, but with one additional lens element. However, it uses the Nikon so-called "Pulse" technology (thus the "P" in AF-P) for autofocus instead of the "Silent Wave Motor" (SWM, or S in AF-S). Pulse autofocus is based on a stepper motor and does indeed appear to be quieter than silent. ;-) While SWM uses a piezo motor driven at an ultrasonic frequency (above human hearing) which in itself should be very quiet, the motor's rotating surface plate in contact with the actual PZT element, associated gear train, and other rotating parts makes detectable noise.

So AF-P lenses return to motor technology with magnets and coils. ;-) As noted above, the "P" is supposed to stand for "Pulse", which kind of applies. They are claimed to be even quieter than AF-S lenses and that is probably true. The manufacturing cost is also much lower. ;-) And there have been comments on various forums about AF-S autofocus reliability, which is quite credible given their complexity and opportunities for contamination to get to the motor. So perhaps a little of both. Replacing the piezo motor with a stepper motor also allows the AF-P lens to be more compact since the motor itself is less bulky and the high voltage drive components and gear train are eliminated.

However, AF-P lenses are not compatible with the D5100 or D3200 (or earlier) cameras that are happy with AF-S lenses. Others like the D5200 may need a firmware upgrade (but that is a free download). And since there is no VR switch on the AF-P lens, VR is always enabled on these cameras since there is no electrical contact in the camera body to control it. (The AF-P version has 8 contacts compared to 7 on the AF-S.) But this incompatibility is almost certainly due to a business decision for planned obsolescence. There would not appear to be any reason why an AF-P lens could not have been designed to look like an AF-S lens as far the the autofocus commands are concerned. Or at worst, with a way of selecting the mode via a switch

The AF-P lens is also significantly narrower than the AF-S VR lens and very slightly narrower than the AF-S VR II lens which could be in part due to the more compact drive setup. The piezo motor has a relatively large diameter (almost 1/2 inch) and the gear train also takes up space. For smaller lenses like these, the only option is to increase its overall diameter. The stepper motor with its direct worm drive can greatly reduce the required space.

The AF-P lens destined for analysis is definitely well worn. The lock button doesn't work properly and in addition, one of the three tabs on the bayonet mount is broken off. Nonetheless, it still seemed to work well enough on a camera. But from the start, its days were numbered. ;-)

After starting the dissection, I had other suggestions for the "P" in AF-P: "Pathetic" or perhaps "Plastic". Nearly everything structural is made of plastic except the screws, some specer rings/shims, and a few tiny brackets. The sleeve/barrel that "programs" the motion of the lens groups based on the zoom setting is a polished anodized aluminum cylinder with precision milled slots in the AF-S VR lens (and most likely the ED lenses that came before it). But it is made of plastic in the AF-P lens, though this change actually occurred with the AF-S VR II lens.

However, having said that, the AF-P lens is much simpler and may be more reliable than its AF-S cousin. Autofocus has only two moving parts - a stepper motor with worm gear shaft which moves an internal lens group over a total distance of around 7 mm using low voltage drive. Compare that to reduction gears in the AF-S lenses along with the possibly tempermental ultrasonic piezo motor. The manual focus ring generates signals to the microbrain that then controls the same motor - it is not directly coupled to it: "Focus by Wire". Vibration Reduction (VR) is simplified as well with no Hall-effect sensors or lock mechanism. As a result, the electronics are also much less complex. In fact, as will be seen below, the electronics is perhaps an order of magnitude simpler in terms of the number parts compared to the AF-S version. This may be largely due to the lack of need for the high voltage piezo drive since the large ferrite inductors or transformers and drive components are eliminated. But may also be due in part to the higher level of integration available at the time of its design. And there are no critical surfaces to get contaminated as with the ultrasonic piezo motor. So I officiatlly retract "Pathetic" because the AF-P lens should be functionally at least as capable as the AF-S version, and more reliable without the SWM, high voltage drive, and gear train.

But it almost appears as though this particular lens must be assembled from the inside-out. :( ;-) For example, in order to get to access any internal parts, the curved strip with contacts that make connections to the camera body must be disassembled down to its individual contacts, which then pop out all over the place. It isn't self contained with the flex-cable as in the AF-S. So if the plastic bayonet mount gets damaged (as would seem to be quite common even though this is a small light-weight lens), replacing it requires some serious manual dexterity. Nikon must have saved 3 cents. ;-)

Taking it to bits non-destructively isn't that bad, though putting it back together without detailed instructions would be like solving a 10-level Rubik's Cube blindfolded. ;-) But that may be resolved soon.

One mystery is solved though with respect to the silent propulsion system for autofocus. As expected and noted above, there is a very small stepper motor (~3/8" diameter) whose shaft has an integral worm gear and no other gears. That rests in a Nylon U-shaped bushing enabling the entire focus assembly with the 3rd lens group to be moved back and forth by around 7 mm with an opto-interrupter as a limit sensor at one end. The focus ring works in parallel with the manual focus electronically: There is an incremental encoder consisting of spokes on the perimeter of the focus ring with a pair of nearly microscopic opto-interrupters in quadrature to sense their movement. So, the stepper motor can be driven either by the autofocus electronics or focus ring essentially at the same time. It's "Focus by Wire". ;-) But manual focus will not work if power is off, which is only of academic interest unless the lens is used in an incompatible camera or for another application. This is fundametally unlike the AF-S version of this lens where the focus ring actually moves a lens group on a helical track and the A/M focus switch selects (1) whether it is coupled to the gear train and (2) lets the microbrain know.

Without a gear train, this should be quieter than the AF-S. The stepper motor itself may make a detectable sound but sliding noise will reduced and there is no gear train to whine. But as a practical matter, the noise level of neither of these lenses is objectionable and only of relevance for some very specific applications where a "Do Not Disturb" sign is present. ;-)

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Optics

The AF-P has 6 lens groups (unlike the AF-S that has only 4), though some may be single lens elements.

The position of the 1st and 2nd-6th (in the same relative position) lens groups move independently depending on zoom setting. The position of the 3rd changes relative to the others depending on focus setting controlled by the stepper motor.

Most of the photos referenced below are also available as a Web Album (though possibly at slightly lower resolution) at Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Parts Web Album.

Here is a summary of the Nikkor 18-55mm AF-P DX f/3.5-5.6G VR lenses I've acquired so far. Also included is a lone non-VR version which I didn't realize didn't have VR until I tested it.:

Nikkor 18-55mm AF-P DX f/3.5-5.6G VR Lenses:

ID #13 and #24 were skipped for no justifiable reason. ;-)

Non-VR Nikkor 18-55mm AF-P DX f/3.5-5.6G Lenses:

Finding a certifiably broken (defined as non-functional) AF-P lens has been a challenge. Sometimes it's a case of the seller testing using an incompatible camera or not realizing the lens won't be recognized if locked. I usually attempt to inform sellers of these possibilities. Really. I haven't gone so far as to ask for a refund because the lens works though and there is ample information available about compatibility including here. ;-) As can be seen, the lock doesn't lock on some of these. Can you say "poor design"? ;-) There is a plastic ridge on the inside of the zoom barrel and gets damaged if attempting to rotate it without pressing the lock button. Or something. So that doesn't qualify as "broken" and can be claimed as a feature, not a bug, as rotating out of the locked position doesn't slow down shooting. And LOCK is pretty irrelevant on these short lenses that don't creep. ;-)

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Disassembly

Not all of the following is needed depending on whether this is for repair or curiosity. Specifically, to replace the plastic bayonet mount requires a much simpler and lower risk procedure. See the section below.

Do NOT disassemble this (or any similar lens) if the future of the Universe depends on getting the thing back together in a functioning condition. At lest not if it's your first (or tenth) one. ;-)

That's basically it. There are now a pile of parts where there used to be an AF-P lens. ;-)

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Resassembly

Reassemble in reverse order, left as an exercise for the student or masochist. ;-) More to come.

I have been able to reassemble it into a mechanically correct configuration, though that was a challenge. While it's reasonably straightforward to get the major pieces screwed into their proper place, fitting them into the appropriate combination of grooves and slots in the cylinders that control how far each one moves as a function of zoom is a challenge. There are probably match-marks in conjunction with jigs that to the trained (Nikon) eye would make this intuitively obvious. The parts now move in what appears to be the correct way based on zoom, but that was through random chance. There are 3 separate assemblies that move based on zoom that need to go into their respective grooves and slots, and also need to be correctly oriented with respect to the quasi-3-fold symmetry of the lens, so among other things, the zoom distance labels, and mark and lock line up correctly. This will become more straightforward with experience, but certainly is a challenge the first time.

And having been successful with the AF-S VF II, I am optimistic that this one will yield to enough determination.

The more I look at these, the more they appear to be marvels of engineering down to the casting/molding of the numerous circuitous groves, slots, holes, posts, blocks, and other structures in plastic. It's probably just Zoom Lens Design 101 but still impressive to the uninitiated. ;-) Unfortunately, sometimes they aren't strong enough as will be seen with the 18-70mm lens, below. :(

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Bayonet Mount Transplant

Failure of the plastic bayonet mount on these lenses is fairly common. It probably is more due to attempting to install the lens on a camera when it's not seated properly than from physical abuse while shooting. This AF-P lens appears to be unique in that the bayonet mount is part of the molded rear shell. And as noted above, it is also unique in that the camera contacts are not secured in a separate assembly but will pop out as the back of the lens is disassembled. This in itself isn't terrible but it's important that none get lost. This transplant can be performed without unplugging the flex cable or going inside the lens. As always, do this on a padded surface with a lip so tiny screws and other parts cannot roll away.

Disassembly

  1. Set Zoom to 55mm to retract the Rear Lens Cluster inside the lens.

  2. Remove the three screws securing the Rear Cover Ring. It is possible that one is longer than the others. If so, make a note of it. Remove the Rear Cover Ring and inspect it for damage, which isn't that likely. It's not what usually gets abused. Set it aside.

  3. The eight Camera Contacts should still be in place, weakly held there by their spring force. It's simplest and safest at this point to use something pointy to pull them out so they can be set aside on your terms, rather than jumping all over the place in the next step. Inspect them for damaged (like being squashed).

  4. Remove the single screw securing the Camera Contacts Housing with its flex cable, which will now come loose. (If the individual Camera Contacts were not removed in the previous step, they will all fall out now.) DO NOT detach the flex cable unless it is faulty, it can stay in place throughout this procedure. It will generally be out of the way most of the time.

  5. Carefully remove the Rear Shell with Bayonet Mount from the lens. There is a single grounding contact having a ball-end with a spring behind it that pokes through the Rear Shell. It may not come off but if it does or is loose and seems like it wants to come off, set it aside in a safe place.

Unless the replacement Bayonet Mount is from another similar lens, it probably does not come with the Aperture Actuator Assembly (long plastic tang, metal lever, and plastic ring with spring). So this will need to be transferred. It is the most fiddly of all the steps. ;( ;-)

  1. Detach the tiny spring that provides the restoring force for the Aperture Actuator. Take care that the spring doesn't escape to be lost forever and doesn't get stretched or deformed. An unbent metal paper clip may come in handy here, and then to replace it below.

  2. Take a photo of the metal Aperture Lever to record its exact position so it can be reinstalled in the same place.

  3. Remove the two screws securing the Aperture Lever and set them aside with it.

  4. Rotate the Aperture Actuator Ring clockwise until it can be freed from the Bayonet Housing.

Reassembly

  1. Install the Aperture Actuator Ring in the Bayonet Housing. It only fits one way and should drop in easily and rotate back and forth without any resistance.

  2. Install the Aperture Lever using its two screws but do NOT fully tighten them. The Aperture Lever being in place will prevent the Aperture Actuator Ring from popping out.

  3. Install the spring. This is by far the trickiest of all the previous and subsequent steps. ;( ;-) My approach is to hook it on the plastic peg that points toward the outside of the ring and then use a slightly hooked end of a small wire paper clip to pull the loop over the peg that points along the ring away from the other one. If that makes any sense! Keep a finger on the other end of the spring while doing this so if it slips, it won't go "twang" into a pile of debris on your workbench or floor or in your trashcan. Confirm smooth operation of the Aperture Actuator.

    (It may be possible and simplier to install the spring as part of Step 1 by slipping its ends on the two projections before rotating Aperture Actuator Ring into position.)

  4. Confirm that the single grounding contact with its spring is still in place, or replace it if not or it was removed above.

  5. Install the Rear Shell with the Bayonet Mount and Aperture Actuator back onto the lens after aligning the index mark on the shell with the one on the front of the lens. Confirm that the Aperture Tang has engaged inside. Test for smooth operation over the entire range of the Aperture. Check that the ball-end of the grounding contact pokes through its hole.

  6. Secure the Rear Shell with the three screws removed previously.

  7. Gently position the Camera Contacts Housing with its flex cable into its position and secure it with the single screw removed previously.

  8. Install the eight Camera Contacts by gently slipping them in place individually. If any seem to be too "flat", carefully spread them out a bit.

  9. Temporarily place the Rear Cover Ring in position and adjust the Aperture Lever (With its screws loose) so it just touches the edge when in the relaxed (aperture stopped down) position. Remove the Rear Cover Ring and tighten the Aperture Lever screws. Confirm that it hasn't moved, repeat if necessary. Secure the Rear Cover Ring with its three screws.

  10. Finally, use a thin blade to carefully lift up one end of the serial number sticker so it can be peeled off and transfered to the replacement Shell. Add a bit of adhesive if it doesn't stay in place securely.

That's it! This should be a wrap. ;-)

Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Dissection

Similar to the one for the AF-S VR II lens, Coming soon, maybe. But for now, there is a Web Album at Nikon AF-P DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens Dissection Web Album with some stock photos and optical architecture and how the lens groups move with zoom.

Comparison of Nikon AF-S DX 55-200mm Zoom Lenses

These are a popular 2nd lens after the kit lens as they cover the long telephoto range from 55 to 200 mm (equivalent to approximately 83-300 mm for the full frame FX format). Given the weight of the 18-300 mm lenses, carrying around this pair makes a lot more sense unless one needs to instantly switch from wide angle to telephoto (or would like to go into arm wrestling). The 18-200 mm lenses are HEAVY. But one deficiency with 55-200mm lenses is that the closest focus distance is not so close - 0.95 to 1.1 meters depending on the specific version. 

            Gener-   (1)     Auto-   Focus     Focus       Manual       Year
   Model    ation   Optics   Focus  Encoder  Tachometer    Focus     Introduced
--------------------------------------------------------------------------------
 AF-S ED      1   2C/9G/13E   SWM     Yes     Magnetic   Mechanical   2005?
 AF-S VR     1.5  2C/11G/15E  SWM     Yes     Magnetic   Mechanical   2007?
 AF-S VR II   2   2C/9G/13E   SWM     Yes     Magnetic   Mechanical   2007?

  1. E: Lens Elements; G: Lens Groups; C: Lens Clusters. Lens Elements are individual optics which may be glass, Extremely low Dispersion (ED) glass, or plastic, and may be normal (spherical) or aspheric. Lens Groups may be a single Lens Element or a glued combination like an achromat. Lens Clusters are my terminalogy for the sets of Lens Groups that move when changing the zoom setting. There will also be a focus group which will be part of one of the lens clusters and moves with respect to it. See the specific lens architecture diagrams in the lens dissection Web Albums for details. A Web search for the specific model lens may also turn up more on the optical design.

  2. It is interesting that the VR II may be more similar to the ED than the VR, although it is not yet known if the actual lens elements are the same.

A montage showing stock photos of all known versions of the 55-200mm lenses as of 2022 may be seen at: Nikon AF-S DX 55-200mm f/4.0-5.6 Zoom Lenses. These are from Nikon lens product or review pages (copyright © Nikon Corporation) scaled so the relative sizes are close to correct. What's remarkable is how much larger the VR version is compared to the others. And then with the VRII it seems they decided "never mind". ;-)

More to come.

Nikon AF-S DX 55-200mm f/4.0-5.6G ED Zoom Lens

There is a repair manual on-line for this lens. Search for "Nikon AF-S DX Nikkor 55-200mm f4-5.6G ED Lens Factory Service Manual" (without the quotes). It's the first hit using Google.

This is a basic lens without VR.

I have had 3 of these:

I am currently evaluating how well swapping of the 1st Lens Groups on these lenses work without adjustments. There are the normal shims between the lens group and focus ring whose main purpose is to fine-tune the position of the 1st Lens Group so the lens can focus correctly at infinity. But #1 also had a pair of half shims on one side apparently to tilt the lens group slightly. It's not clear if that is a lens group issue, or lens focus ring or body issue. Can you say "kludge"? ;-) Considering how much free play there is in all these plastic lenses, it's not clear how much that would help. But perhaps #1 was a particularly bad specimen.

Stay tuned.

Removing the 1st Lens Group in the Nikon AF-S DX 55-200mm f/4.0-5.6G ED Zoom Lens

The repair manual doesn't seem to even address this, but only deals with the removal and replacement of the entire front assembly. However, it turns out that the 1st Lens Group consists of a pair of lens elements mounted together in a housing which unscrews counter-clockwise. This was indicated by the pair of tiny holes for a spanner wrench revealed once the label was removed. But it turns out that this isn't even necessary. There are at least two ways to proceed. For both, first switch to manual focus and adjust focus and zoom so everything is fully extended. Grip the lens by the filter mount to minimize stress on the internal parts of the lens:

  1. Carefully peel off the label by slipping a thin stiff piece of plastic under it to lift one edge. Then go around the perimeter with a round wooden toothpick to free it. Alternative "tools" may be used. ;-) This is somewhat risky and there is a good chance the label will be damaged cosmetically in the process.

    With the label removed, a pair of holes for a spanner wrench will be visible, which is probably what Nikon uses since they have plenty of labels. ;-) Using a spanner is less stressful on the lens than #2 below. And it has the benefit that the label can be replaced in the original orientation. While the label would line up correctly if replacing it in the lens but not if swapping them between lenses. (A pair of tiny depressions for a spanner could also be drilled through the label 180 degrees apart no more than 1 mm or so in depth in locations avoiding the printing. The label would not need to be rmeoved and the cosemtic damage would be minimal.)

  2. An alternative which doesn't require removing or damaging the label uses a home-built "tool" consisting of a piece of 1-1/2 inch ID PVC pipe or coupling and double-sided tape or rubber glued to its end. Confirm that the end is flat - sand or file it flat if not. The PVC pipe fits the outer perimeter where the label is located perfectly and the sticky tape or rubber provides enough grip that it should be possible to then unscrew the 1st Lens Group. Apply just enough force so the adhesive or rubber does its job. Too much will just increase the required torque. And as noted above, hold the lens by the filter ring / lens barrel.

    This approach is also shown in Nikkor 55-200 : Haze and fungus removal - YouTube, though his lens appears to have been previously repaired.

Once the 1st Lens Group is free, keep track of the shims. Should there be a partial shim or shims, it or they are probably stuck in place with some sort of adhesive and remain there unless the 1st Lens Group is being swapped with one from another lens or vice-versa. In that case, you're on your own. ;( ;-)

Reassemble so it is just snug.

Cleaning Inside the 1st Lens Group in the Nikon AF-S DX 55-200mm f/4.0-5.6G ED Zoom Lens

For some reason, the inner surface of one or both of the elements in the 1st Lens Group seem to be what get contaminated, not the surfaces that are readily accessible by simply removing it.

However, accessing them isn't too involved.

  1. Remove the 1st Lens Group taking care not to lose the shims as described above.

  2. The 2nd Lens Element at the back of the 1st Lens Group is held in place by a ridge of plastic a fraction of a mm across rolled over its edge. Use a fine file to *carefully* remove only the ridge going around its perimeter until the glass edge of the lens element is exposed. Take it slow to avoid damage to the edge of the fragile glass lens element. A single edge razor blade or something similar may be helpful to peel off the remaining sliver of plastic.

  3. Using a calibrated finger nail ;-) or similar tool, chip off a tiny piece of the remaining plastic so that the edge of the lens element is exposed.

  4. Put match marks on the glass lens element and mount so it can be replaced with the same orientation. Perhaps not necessary but won't hurt.

  5. It should now be possible to pop the glass lens element off without damage while retaining the mounting structure so that it can be replaced with the original alignment.

  6. Clean the now exposed inner surfaces of the lens elements with soap and water, lens cleaning fluid, hydrogen peroxide, and/or alcohol. The use of anything stronger is probably not recommended for the 1st Lens Element still in the plastic mount, which could be damaged. Acetone can be used for the other one, but typically that's not needed.

  7. Touch up the edge of the 2nd Lens Element with a black Sharpie™ or something similar if needed.

  8. Pop the 2nd Lens Element back into position with the match marks aligned making sure it's seated on the ridge. Add a few bits of 5 minute Epoxy or similar adhesive around the perimeter to assure it stays there.

  9. Reinstall the 1st Lens Group as described in the previous section, above.

Just don't get over zealous in removing the 2nd Lens Element as I did and chip the edge, which could impact photo quality at low f/ stops. At the very least, it's ugly. ;(

Nikon AF-S DX 55-200mm f/4.0-5.6G VR Zoom Lens

I have not found a repair manual or even an exploded diagram for this lens. It is quite different than the original ED version or the VR II succesor in external construction and possibly optical architecture. If anyone has one for this lens, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

I have four samples of this lens:

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR Zoom Lens Description

The 55-200mm VR lens is the largest and heaviest of the three which makes it much less desirable than the VR II version. It uses the typical SWM but with a fully enclosed gear train and a drive frequency of around 70 kHz based on measurements using a sense coil and scope.

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR Zoom Lens Disassembly

This is only partial at present down to the level of exposing the SWM and PCBs.

  1. Remove the single screw securing the Switch Panel, swing it out revealing the interior of the Switch Bay, Unplug the flex cable by flipping up the locking level or by holding the connector with a pair of tweezers and pulling it out.

  2. Unsolder the thin grounding wire from the pad. Alternatively, cut the wire leaving enough at either end to strip solder during reassembly. Only if you do not have any way to solder should you consider unscrewing the grounding contact assembly from the Bayonet Mount which will be exposed when the Bayonet Mount is removed. It's almost impossible to get this back together without more hands than are standard equipment.

  3. Remove the 3 screws securing the Inner Ring and remove it.

  4. Remove the 2 screws securing the Camera Contact strip and gently push it toward the center of the lens so it is loose.

  5. Remove the 3 screws securing the Bayonet Mount. Lift it up and disengage the Aperture Tang from the prong on the iris diaphragm. Unlike most other lenses, this does not slip in place - the prong should bd lifted as far from the lens as it will go and then it should disengage. but it may be necessary to gently push the iris prong toward the center of the lens with a thin tool. This may require zoom to be set away from the 55 mm position.

  6. Add a small dab of 5 Minute Epoxy or something similar to the ground contact where the wire is soldered. Otherwise there's a good chance it will break off with even modest handling.

  7. There are anywhere from 1 to 4 or more shims under the Bayonet Mount. Label them as to orientation and top/bottom. If more there is more than one, also label their position in the stack though it really shouldn't matter. So arrange them with the thickest one on the back (top) which will make it easier to set them in place during reassembly. Sticking them together with adhesive in a way that doesn't change the overall thickness would also greatly simplify the fiddlyness of reassembly where more than one shim is present. A single wrap of thin Kapton tape away from any of the screw holes may be satisfactory. FWIW, ID #1 had a single thick shim while ID #2 had 4 - two thick and two thin. My guess is that a combination of binary thicknesses (i.e., 1, 2, 4, 8 units) of shims is selected during final testing to fine tune the optical location of the lens with respect to the camera body. Or something. ;-)

  8. Remove the Fixed Shell.

At this point, everything that is simple to get at on the back of the lens is exposed.

  1. Remove the Rubber Grip by carefully lifting it along one edge and working it free of the Zoom Barrel.

  2. If it is desired to inspect the Zoom Encoder, peel off the tape securing the black cover sheet. It can be replaced with Kapton tape.

More to come.

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR Zoom Lens Reassembly

To use the lens on a camera without the Fixed Shell to inspect its innards or probe signals like the SWM drive, simply leave the Fixed Shell off during reassembly. The lens won't be quite as robust without it and high voltage (~240 VAC) will be present on some components and solder pads when focusing, but with care it should be perfectly satisfactory for testing at least. CAUTION: This stunt appears to be acceptable for the 55-200mm VR lens but may not be for some others where the closeup and/or telephoto zoom limits depend on stops on the interior of the Fixed Shell. For those, bad things may happen if rotated beyond them! ;-(

Reassemble in reverse order. The most fiddly part of reassembly (after making sure the shipm stay in place) is probably reattaching the ground wire. If soldering back to the pad on the flex cable, cover the edges of the Switch Bay with Kapton tape or something similar to protect the plastic from accidental contact with the soldering iron tip. The wire was cut, stip the ends and solder them together, finally insulating with Kapton tape, plastic electrical tape, or a glob of 5 minute Epoxy. Coming someday.

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR Zoom Lens Dissection

The start of a dissection is available at Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR Zoom Lens Dissection Web Album. So far it goes only as far as was required to repair ID #2 and described in the disassembly steps, above.

More coming soon.

Nikon AF-S DX 55-200mm f/4.0-5.6G VR II Zoom Lens

I have not found a repair manual or even an exploded diagram for this lens. It appears more similar to the original ED version than the VR predecessor in external construction and possibly optical architecture, but with VR and the Lock button added. If anyone has one for this lens, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

This is a rather nice relatively compact lightweight lens. It looks somewhat like an AF-S DX 18-55mm VR II lens on steroids and only very slightly larger than the 55-200mm ED version, both of which are shorter than the VR version.

Since neither of these is really broken, the search is on for a third speciment for dissection and to repair ID #2.

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR II Zoom Lens Photos and Description

The 55-200mm VR II lens is the most compact of the three which makes it much more desirable than the VR version. It uses the typical SWM and gear train but with a drive frequency of around 290 kHz based on measurements using a sense coil and scope. It also has the dither pulses continue for a few seconds after focusing like some of the other AF-S lenses.

Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR II Zoom Lens Photos and Description

The start of a dissection is available at Nikon AF-S DX Nikkor 55-200mm f/4.0-5.6G VR II Zoom Lens Dissection Web Album. But only stock photos, dimensions, a partial optical architecture diagram, and external photos.

More coming soon.

Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens

There is a repair manual on-line. Search for "Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5 Zoom Lens Repair Manual" (without the quotes). It's the first hit using Google.

Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens Description and Dissection

This lens is interesting because autofocus uses a full diameter ring ultrasonic motor with no gears, which is why I bought it for dissection. These are called "Silent Wave Ring Motors", "Ring SWM", or for the geek types: Ultrasonic Piezo Silent Wave Ring Motors - or anything in between. Theoretically, they should be quieter, more reliable, and faster. But in reality, they may not be unequivocally any of these. The working sample I have is definitely not silent. And they are probably more expensive to manufacture even though there are fewer parts.

Autofocus on this lens is quick, but not necessarily quieter than on the AF-S lenses using the small motor and gears. The motor and lens has sliding surfaces which still make some sound.

But the sacrificial victim (ID #2) makes abnormally loud grinding noises and fails to be able to focus correctly - either manual or auto. :( ;-)

The cause became obvious as a huge part - the entire 2nd lens group - was loose inside the lens not attached to anything just bouncing around. ;-( Figuring that the 1st lens group would detach like the others - by unscrewing it after removing the label, that was attempted first. But either it has left hand threads or it is really tight and I don't have the needed spanner wrench, so it remains securely attached. No matter. ;-)

Plan B was to go in from the back, where the action is in any event. This turns out to be quite simple and even reversible. Removing several screws around the side of the bayonet mount and the back allows both to be removed without damaging anything. The electronics PCB is then exposed and its cables can be unplugged easily along with the Focus A/M switch revealing the full diameter autofocus Silent Wave Ring Motor. The contacts remain safely inside their housing.

Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens Photos and Description

Most of the photos referenced below are also available as a Web Album (though possibly at slightly lower resolution) at Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens Parts Web Album.

Being simpler than the VR lenses, there are fewer photos for this one, but there is always the on-line repair manual to refer to:

This lens appears to be more repair-friendly than the ones above especially if there is no need to go inside the assembly with the 7th-13th lens groups. There should be no need to unsolder any wires and the flex cables detach easily. As noted above, just keep track of everything with photos, notes, and added match marks.

However, note that there is a magnetic strip and magnetic pickup that provides a signal in place of the tachometer in some lenses that have the small SWM with gear train. Not only is it delicate and damaged easily, but ferrous tools can cause the magnetic pattern to become corrupted, which needless to say, would not be good. Even accidentally touching the strip with a slightly magnetic screw drive could potentially erase it.

And if you're curious as to how the focus is controllable mechanically both via the Focus Ring and Ultrasonic Piezo SW Ring Motor at the same time, it's similar in concept to a differential gear box but with no gears. Focus is actually controlled by a ring with a metal fork that engages the plastic tab on the middle lens cluster. That is mounted on ball bearings as shown in the photo above. On the front-side is a plastic ring that is in contact with the ball bearings that engages with the rubber/plastic manual Focus Ring. On the back side is the rotor of the PRM which is in contact with the opposite sides of the ball bearings. The friction of the focus fork ring is quite low (or should be) so when the ball bearings are rotated by either the Focus Ring or Piezo motor rotor, it moves at 1/2 the rate of either but does not (or at least should not) affect the other ring. However, where the lubrication had gummed up or there is damage from abuse, movement can be inconsistent. This appears to be a common problem with the AF-S DX 18-200mm f/1:3.5-5.6G VR and VR II lenses (below) where focus fails to work properly over part of the Zoom range or at all.

There are no immediate plans for a detailed dissection but for now see the Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens Dissection Web Album. There is no dissection yet but it shows some stock photos and the optical architecture and how the lens groups move with zoom.

Attempted Rebuild of Nikon AF-S DX Nikkor 18-70mm f/3.5-4.5G ED IF Zoom Lens

For lack of something better to do I purchased a partially disassembled 18-70mm lens to try to make one good lens out of the two. I was only $17.50 delivered. This one has an intact focus group but no PCB or bayonet mount and related parts. I opted to complete it using parts from the lens with the broken focus lens group since only the parts in the back were missing. The repair manual is useful for this. And aside from some partially stripped holes and melted A/M switch ;( it went together without incident, the camera recognizes the lens and even reads the zoom setting correctly (confirmed via the EXIF info). The autofocus PRM works but focus lock is only achieved if it is already very close to the optimal focus. Otherwise it womps back and forth from end-to-end of the focus range. So it could be that the focus tachometer is faulty or disconnected. It works fine with manual focus. With the mangled A/M focus switch, it cannot be set to manual focus, but autofocus can be disabled on some cameras.

While in principle, it would probably have been better to simply swap the focus lens group into the original lens, other parts may have been damaged in the initial discombobulation.

And that's how it will remain!

Nikon AF-S DX Nikkor 18-200mm f/3.5-4.5G VR Zoom Lens

There is a repair manual for this lens with detailed disassembly and reassembly procedures above the level of the VR assembly, which is common for these manuals. None have anything deeper. However, this one is quite detailed and does include the removal and installation of the VR assembly ("VR unit" as they call it).

I purchased 4 of these to date described as "For Parts or Repair". All are in very good to excellent physical condition with little evidence of wear and no abuse. All exhibited similar problems except for ID #1:

VR appears to be non-functional on all of them unless I'm missing something to enable it. Yes, I've exercised both the VR ON/OFF and VR Active/Normal switches. Unfortunately, without removing the Bayonet Mount and related parts, the switches cannot be testee as they are part of the Fixed Shell. Other VR lenses work fine on the D70 including the VR II version of this lens.

All of these had a hint of hessitent manual focus at least until exercised a bit but now work fine. This would appear to be a common problem with the 18-200 VR and VR II lenses with their physically long zoom extension. Apparently so is broken VR unless I've been extremely unlucky...... ID #1 is currently at the top of the list for dissection but it may only go deep enough to confirm there isn't a simple fix for the noisly and non-functional VR in which case the VR actuator flex cable will be unplugged to quiet it down. ;( ;-).

There is no dissection yet, but see the Nikon AF-S DX Nikkor 18-200mm f/3.5-5.6G VR Zoom Lens Dissection Web Album. There is no dissection yet but it shows some stock photos, the dimensions, optical architecture, how the lens groups move with zoom, and a detailed drawing of the internal structure.

These photos were taken using one of my trusty D70s with the AF-S 18-55mm ED lens that had a damaged Filter Ring. See: Repairing Broken Focus Tabs on Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G ED Zoom Lens.

Nikon AF-S DX Nikkor 18-200mm f/3.5-4.5G VR II Zoom Lens

I have not found a repair manual or even an exploded diagram for this lens, though it is probably very similar to the VR (not II) version for which there is a manual. If anyone has one for this lens, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

I do have one in mint condition and another that is cosmetically nearly as good but does not always focus reliably, even in manual mode. But there are no current plans for a detailed dissection of either, or even to investigate this lens in greater detail unless someone would like to donate a sacrificial specimen for analysis. The asking prices on eBay are way above may curiosity quotient for a lens to take apart and likely never put back together so it functions. ;-) Appropriate chants and incantations will be issued to the gods of dead camera lenses upon request but it will not likely survive the experience. :( ;-)

However, eventually the one with the unreliable focus may end up being used for this purpose.

But see the Nikon AF-S DX Nikkor 18-200mm f/3.5-5.6G VR II Zoom Lens Dissection Web Album. There is no dissection yet but it shows some stock photos, dimensionas, optical architecture, how the lens groups move with zoom, and the detailed internal structure of the VR version (which should be very similar). A dissection of that lens is likely to happen sooner and is expected to be virtually identical.

These photos were taken using one of my trusty D70s with the AF-S 18-55mm ED lens that had a damaged Filter Ring. See: Repairing Broken Focus Tabs on Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G ED Zoom Lens.

Nikon AF-S DX Nikkor 18-300mm f/3.5-5.6G ED VR Zoom Lens

This lens and its successor (below) are believed to have the highest zoom ratio - over 16:1 - of any Nikon DX lens.

Until recently, I had not found a repair manual or even an exploded diagram for either lens, though this one appears to be very similar to the AF-S Nikkor 28-300mm f/3.5-5.6G ED VR lens for which there are repair and parts manuals from multiple Websites. However, that is FX (full frame) but even the weight is almost the same. So perhaps it really is an almost identical lens that has had its zoom range extended down to 18mm but with unacceptable distortion and/or vignetting for the FX format.

However, as of April 2025, there is a repair manual available for the this lens at Learn Camera Repair Product 1702. There is (currently) a $3.25 charge but it well worth it. Either it appeared only recently or I missed it previously. But this manual does NOT appear to go as deeply as the one for the 28-300mm lens, specfically there is little to no information on the Aperture and VR assemblies at the heart of the lens, these being near the last parts to be removed in any disassembly. But it is better than nothing.

Now back to the lens itself.....

Not to put too fine a point on it, but this thing is HEAVY - 29.3 oz. (830 g), close to 2 pounds.

Summary of the four I have so far (more below):

The first sample of the f/3.5-5.6 version I purchased for study and possible dissection is really well used: The gold lettering is totally gone, the plastic underneath is even worn, and most of the exposed plastic surfaces have a shiny appearance. It largely works but takes truly lousy pictures. :( ;-) That's what I expected as the description stated: "the image quality is not sharp". That is totally accurate but perhaps an understatement! In fact, a pinhole camera would take better pictures. Yet there are no obvious mechanical problems - zoom and manual focus are smooth and consistent. Nothing rattles and it shows no sign of serious trauma except for some small chips on the edge of the filter ring. But the focus, zoom, and filter rings appear to be well aligned with only the typical small amount of free play that these lenses tend to have. Autofocus is fairly reliable except perhaps when zoom is near 18 mm. This may be a clue, though manual focus works over the entire range. VR works well as confirmed on my VR Test Rig. But the image quality is totally dreadful at large apertures and even when stopped down to f/32, there is serious fuzziness and color fringing over a large part of the frame especially when zoomed way in (300 mm). This suggests that a lens element or lens group may have come loose and is sitting at an angle, though the interior looks pristine with no visual evidence of misalignment or wondering elements. All the visible optical surfaces are clean without any evidence of fungus, dust, deterioration of the AR coatings, or other unsightly blemishes. The behavior can only really be attributed to misalignment of one or more elements. The label on the front is dented in one location and rotated almost 180 degrees from the normal orientation with "Nikon" at the top, so someone has probably at least removed the label and perhaps the 1st Lens Group to look inside and at the very least, they didn't pay attention to the label when it was reattached. It has no keying so that doesn't imply anything about much of anything. I can't tell if the 1st Lens Group was removed for any reason but there is a mark on it that lines up with the white dot on the Filter Ring so it's probably installed correctly. Such major abberations wouldn't even seem likely from simply being misoriented in any case. But if an asymmetric shim was out of place, that would not be obvious. I have seen at least one instance on another lens where there was only a partial shim ring. The inside looks pristine. And if any parts were left out ;) or installed incorrectly, it almost certainly would not work as well as it does, even if that isn't saying much. ;-)

I also have a near-mint 18-300mm f/3.5-5.6 lens. But based on a quick visual inspection, it appears physically identical when viewing the inside front and back, zoomed in and out. But almost any random shot taken with it is far superior to anything the defective lens is capable of even when stopped way down.

So I decided to see of changing the orientation of the 1st Lens Group or the location of any shims would make a significant difference.

My conclusion is that the cause of the poor performance has nothing to do with fine alignment of the 1st Lens Group. It's so bad that those things are buried in the weeds. So back to square one.....

Here is a montage of shots taken of a test chart at around 105 mm and f/5.6, 8, 16, and 32): Defective Nikon AF-S-DX-18-300mm-f3.5-5.6G-ED-VR #1: Zoom 105 mm Comparison. Zoom of 105 mm was selected simply because the chart filled the frame. (70 mm would be closer to the mean between 18 and 300 mm.) But it's no better anywhere else.

Next, a HeNe laser beam was passed through the lens as on-axis from the input side aligned so that it passes centered through the stopped-down aperture. The beam has a near-perfect Gaussian profile with negligible scatter. The objective was to both look for the character of the reflections from the internal lens elements, and for any degradation of the quality of the Gaussian beam on a screen placed after the lens.

On the good lens, there are a multitude of reflections but they are very weak as would be expected from high quality anti-reflection coated surfaces and can be totally superimposed in the reflection. On the bad lens, there also a multitude of reflections but 1 or 2 cannot be superimposed on the others. Exactly where they are coming from is unknown but is probably from an element before the aperture. The reflected spot is very small suggesting it is near the front of the lens but that can be confusing due to the combination of positive and negative lens elements. At first there was a bright off-axis spot which I got excited about. But that turned out to be a red herring: It was from the cheap non-AR-coated UV filter on that lens but not the other. The bad lens shows a bit of interference fringes on the transmitted beam while the good lens does not. These tests were done at a zoom setting of 18 mm. I'm not sure I'm determined enough to repeat them at 300 mm without a more stable fully adjustable test setup. ;-)

So the 18-300 mm question is: Having eliminated 1st Lens Group alignment from consideration, what is the most likely part to fail from a minor traumatic event like whacking the filter ring or just from wear and tear? If the VR armature or its lens popped off the suspension or got stuck to one side, VR would not work at all. But VR works great. If any other lens group came off its tracks, there would be obvious problems with zoom or focus. Only if a lens element or elements) came unglued within their housing(s) could there be optical problems but no mechanical problems. If anyone actually reads this stuff ;-) and has a similar experience, knows the answer, or even has a wild guess, please contact me via the Sci.Electronics.Repair FAQ Email Links Page. For now, I'm not intending to go any further inside.

Of note is that even perfect specimens of the 18-300mm f/3.5-5.6 lens have significant distortion and chromatic aberration of varying degrees over various portions of the zoom and focus range. Achieving decent performance over a greater than 16:1 zoom range is challening. But modern DSLRs digitally process the images to largely correct both geometric distortion and color fringing using lens-specific data stored in memory (part of the camera firmeware). So the end-user may never see most of these. unless they are obsessive-compulsive and search for defects like that. It may be surprising how mediocre its performance really is when viewing the raw image data. And this lens has 19 lens elements. That's 38 anti-reflection-coated surfaces the light must traverse, which will have some effect on general sharpness, flare, etc. (But none of that can be corrected in-camera.)

Being slightly disappointed with the performance, I even contacted Nikon via their Website with the serial number to see if they would tell me anything about that specific lens but of course that was hopeless. Their reply was that they don't have any information and suggested that I send it in for service. ;( ;-)

And a trivial triviality common to both (and I assume to all of these): The zoom marking for 200 mm seems to correspond more to somewhere between 225 and 250 mm, NOT 200 mm based on the image size compared to the 300 mm position. I've not seen any mention of that in the reviews of this lens or on Nikon lens forums.

How far it goes will depend on when - if ever - the cause of the lousy pictures can be found. My guess is a lens group that has been knocked out of position, or perhaps the VR Lens Group even though VR appears to work well. If one of the springs in the VR assembly popped off, VR might still appear to work.

For the start of a dissection, see Nikon AF-S DX Nikkor 18-300mm f 3.5-5.6G VR Zoom Lens Dissection Web Album. This will be guided by the repair manual but there will be significant deviations. ;-)

And yes, you aren't hallucinating. There are closeups of a piece of cloth and shots of an ancient digital computer light and switch panel amongst the dissection photos. The reason for these is explained later below. ;-)

Here are some more comments on the dissection photos:

Now for more details.

The first part of the dissection dealt with removing the Front (1st) and Middle 1 (2nd) lens clusters. They appear pristine and there is nothing obivous inspecting beyond those from the front. There is evidence that 2nd Lens Cluster had been removed previously but I can't rule out that being my doing.

ThAt state of disassembly offered a possible way to confirm that the problem was still present and associated with the back of the lens. It turns out that with the 1st and 2nd Lens Clusters removed and Zoom set at 18 mm, an "object" against the front of the Zoom Barrel (just behind the edge of the Filter Ring) will be in sharp focus in the camera. Whether there is some cosmic significance to this with respect to the lens design is not known but it is a remarkable coincidence. ;-) The area covered is around 1.0 x 0.6 inches, close to the APS-C DX format. So a 35 mm slide (remember those?) or 35 mm negative, a textured surface, or something similar can be secured there with masking tape. If it is too close, Zoom can be used for manual focus since it moves that surface without affecting anything else significantly over the small range required. (Focus would not do anything without the 2nd Lens Cluster installed.) There is a small amount of pincushion distortion but one can't have everything. ;-) And a photo editor like Evoto will easily correct that. Preliminary results are encouraging in confirming the problem is with the back section of the lens:

The photos titled: AF-S-DX-18-300mm-f3.5-5.6G-ED-VR_No_1st_2nd_Lens_Clusters_Cloth1_f5.6, f8, f16, and f29 were taken using a D5600 of a piece of fine thread cloth positioned at the lens's sweet spot using similar aperture settings to the test chart photos. The same asymmetric fuzziness appears to be present.

The photos titled: AF-S-DX-18-300mm-f3.5-5.6G-ED-VR_No_1st_2nd_Lens_Clusters_Univac_1830_Console_Slide1_f5.6, f8, f16, and f22 are of a 35 mm Kodachrome slide originally taken in the year 1978 using a Nikon Photomic FTN body with f/1:1.4 50 mm lens of the operator's console of a Univac 1830 (CP-823/U) avionics computer prototype from the early 1960s. (For some obscure reason the D5600 refused to stop down beyond f22 for these shots even though it was set to Manual exposure.)

(For the techno-dweeb types and having nothing to do with this lens, the Univac 1830 was a 30 bit computer that had a whopping 32,768 words of core memory and utilized flat-pack SSI integrated circuits for most of its logic. Wikipedia CP-823/U has more including a photo of the nine massive electronics boxes that comprised the actual computer, all of which I had at one point along with two or three cartons of garden-hose diameter cables. The photos of the console there are ones I contributed. The first one is derived from a scan of the exact same slide used for this dissection. These may be the only color photographs of the 1830 in existence today.)

For comparison, the photo titled: AF-S-DX-18-300mm-f3.5-5.6G-ED-VR_Univac_1830_Slide_with_Macro_Lens1 was taken of the same slide using an AF-S DX Micro Nikkor 40mm f/1:2.8 Macro lens with the slide mounted approximately 2.5 inches in front of the lens with a light diffuser and cropped to show the entire 35 mm frame. This is a fairly accurate comparison of the area of the original slide and the smaller coverage of the hacked 18-300mm lens along with its pincushion distortion.

Next was the dissection of the back of the lens. The Back Lens Cluster also appears to be in perfect condition - at least until I disassembled the two sections with the 12th and 13th Lens Clusters and 14th Lens Cluster, which is something that should not be done without the proper tools and test procedures to realign them!)

But here again, the lens cooperated in that with *only* the Aperture/VR assembly still present, the lens would focus as a macro lens over a range of a few inches.

And the shot of the laser spot seems to rule out the AP/VR Lens Cluster as the cause of the problem. Which means the lens should have performed flawlessly. Too bad that it didn't understand that. ;-)

I decided to put it back together. It was straightforward since nothing except the one Light Shield was damaged Using the same laser, it should be possible to align and reassemble the Back Lens Cluster. It's just a matter of screwing the 2nd Lens Cluster (Focus) back in. And while the location of the shims for the 1st Lens Cluster are suspect, any effects from them being arrange incorrectly should be small.

Everything has been reinstalled except for the label, light shields, front lens cluster shims, and rubber boot. The back lens cluster lens groups were centered as best as possible without going to the extreme a laser. ;-) The last photo in the Web Album shows the reassembled lens. The lens still takes truly lousy pictures. It's hard to tell if they are worse than before since they were already terrible. And it's also hard to tell if the character of the faults has changed as a result of alignment or anything else, but it's not dramatically worse. Probably no more than additional flare resulting from the lack of the light shields.

And that, as they say, is that. ;-) Deeper dissection of this specific lens is probably not going to happen. However, if someone has a certifiably dead sample of the AF-S DX 18-300mm f/1:3.5-5.6G ED VR lens they would be willing to donate to the cause, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

Nikon AF-S DX Nikkor 18-300mm f/3.5-6.3G ED VR Zoom Lens

This is the newer and lighter version of 1the 18-300 mm lens but it has lost a fraction of a stop at the high end - 6.3 versus 5.6 which is considered mostly irrelevant with modern DSLRs. Its weight is 19.4 oz. (550 g), about 2/3rds that of the 18-300 mm f/3.5-5.6, which is actually slightly less than that of the 18-200 mm VR II lens - 19.8 oz. (560 g). It must use a lot more plastic! :( ;-)

I am not aware of any on-line service manual for this lens, which appears to differ significantly compared to the previous 3.5-5.6 version (above, for which there is a service manual).

Nikon AF-S FX Nikkor 28-300mm f/3.5-5.6G ED VR Zoom Lens

There is a repair manual on-line for this lens. Search for "Nikon AF-S Nikkor 28-300mm f3.5-5.6G ED Lens Factory Service Manual" (without the quotes). It's the first hit using Google. Though now it seams that the Learn Camera Repair Website is charging a small amount for these manuals. It is worth the cost just for the information value even if you have no intention of disassembling the lens. But if you're a cheapskate, it's still free at ManualsLIB.com (as of April 2025).

This a full frame (FX, 35 mm) lens so it really has no business being here. ;-) Actually, it does. An FX lens will work fine with a DX camera. It's just a bit of a waste since ~half the picture area is outside the DX frame. The main reason it IS here is that its construction is believed to be very similar to that of the DX 18-200mm and 18-300mm lenses AND one was found on eBay just over $125 that is optically in very good condition but certifiably very broken mechanically - something is loose/rattling around inside including aperture parts which hvae been mangled, and the aperture is always wide open (but partially blocked by the parts floating around inside the lens!), Zoom gets stuck with serious dragging and grinding and doesn't go out beyond ~32 mm (never to 28 mm), focus is temperamental, VR seems dead, and there may be a motorized ratcheting noise when first powered. Aside from those minor issues, the lens is in perfect operating condition. ;-) And it does take decent photos when it feels like it (if you don't mind the aperture being more or less wide open). ;-) In any case, mostly complete dissection has been performed - as far as necessary until the sources of the problems are located - which is down to the level of removing the Aperture and VR assemblies. Which is to say, a nearly a total disassembly.

See the Nikon AF-S FX Nikkor 28-300mm f/3.5-5.6G VR Zoom Lens Dissection Web Album. (The first few are all either Nikon stock photos or those from the KenRockWell.com Website (which appear to include some Nikon stock photos!), then the lens architecture diagram, after that are all of the distressed lens itself. Those photos were taken with a Nikon D90 using a Nikkor AF-S DX 18-55G VR II lens on a tripod without VR (it's dead on that lens anyhow) and remote shutter release. Most are illuminated by a ~16x16 inch LED fixture with a uniform diffuser ~16 inches above the shooting area. The camera's White Balance is set to Fluorescent Cool White and minor picture adjustments are done in post processing. The background is a single sheet of glossy white paper. There has been no background removal partially because those programs that generate images with decent resolution are no longer free as they were for the earlier dissections, or are now too cumbersome to use with multiple photos. But with the white background for most, there is little need for it. Those without a white background were done that way to enhance the appearance as needed.

The first block of photos after the lens architecture diagram show the intact lens. The shiny complexion is not an artifact of lighting, it definitely appears that way having seen lots of use, but no actual physical trauma is evident. The broken aperture actuator plate or a piece of it is visible in the view through the front of the lens. ;-)

The dissection will be guided by the disassembly procedure in the repair manual, skipping those steps that are irrelevant. A substitute for at least one special tool may need to be improvised. While a reasonable effort will be made to avoid unnecessary destruction, some damage will almost certainly occur. But the aperture mechanism is already history and there has likely been irreversible havoc caused by the crunching and grinding during Zoom and other scary sounds from Autofocus. Live with it. ;-)

The next 15 or so photos after the lens architecture diagram are of the intact lens. Then the fun begins. The next block of photos are based on the disassembly procedure in the repair manual starting at the front of the lens. So, removal of the Filter Ring, 1st Lens Group, and 2nd Lens Group. The checkered yellow and white background is used for some photos of the lens group parts to give more depth to them. There is also a photo of the two pieces of the aperture mechanism that were floating around inside. The one on the left - the Aperture Actuator Plate - is missing the actuating tang and was originally totally folded in half! And the one on the right had to be partially folded to extract it through the hole left by the 2nd Lens Group. With those removed, Zoom is reasonably smooth and the crunching noises are gone. However, the aperture return spring is missing and Zoom still does not go below around 32 mm, possibly due the missing spring and/or tang being jammed in there somewhere. The missing aperture leaves probably wouldn't account for it.

As the dissection has progressed further at the back of the lens, several mangled remains of the aperture leaves have fallen out. Three at first, then after removing the Main and SWM PCBs, three more along with a metal tang broken off the Shutter Actuating Plate, and the final three after the lens was disassembled down the Zoom Telescope Mechanism (my terminology). ;-) And the aperture return spring was found in-place with one end still attached by a dab of adhesive. That metal piece may have been what was interfering with Zoom because now the full range has been restored. If the lens was only used for shooting at the wide open 1:3.5-5.6 aperture (using aperture priority or manual control), it could now be reassembled in perfect condition. ;-) That's tempting but there is probably little demand for a lens that only works at maximum aperture. The aperture assembly for this lens doesn't appear to be something that appears on eBay! ;-( ;-)

The dissection is now complete. The assembly that wasn't totally taken to bits is what the Repair Manual calls the "2nd lens-G straight ring unit". It's a pair of concentric cylinders with screws, guides, bearings, and springs which would like nothing else than popping off and getting lost. Otherwise, it's pretty much as described in the Repair Manual, though some steps were done out of order by accident or by design. As best as I can determine, nothing has been damaged so were an aperture assembly for this lens to appear on eBay at an affordable price I might consider attempt a restoration.

One interesting observation is that the VR Gyro ICs (PN: XV-3500CB) are on the Main PCB and SWM PCB, rather than having a separate assembly of their own. The PCBs are mounted at right angles to each-other.

Stay tuned.

Nikon Z DX Nikkor 16-50mm f/4-5.6 VR Zoom Lens

There is a repair manual for this lens available directly from the Nikon | Self Service Repair Website. Yes, there is now such a thing direct from Nikon no less which apparently is quite recent and only deals with Nikon Z gear. That is the good news. The bad news is that for this specific lens, it has virtually no useful information. In fact the number of pages devoted to notices, cautions, and warnings - most of which are totally irrelevant for a lens - outnumber those with repair information. However, some other repair manuals are much more comprehensive. So worth checking out in any case.

The Nikkor Z DX 16-50mm f/3.5-5.6 VR lens is the most compact zoom lens for Nikon Z cameras. Its reviews are actually pretty good for a mostly plastic (except for the optics) lens. The optical architecture is simpler than other lenses with a similar zoom range, specifically the AF-P and AF-S DX 18-55mm "kit" lenses - only 7 optical elements versus 12 for the AF-P 18-55mm. Of course their minimum aperture is larger by an extra fraction of a stop. ;-) A comparison of these two lenses is shown in Nikkor Z DX 16-50mm f/1:3.5-6.3 VR Z vs AF-P Comparison1. While the zoom range for the AF-P is also wider by around 10 percent, these don't account for its dramatically larger size. But this diminutive lens does look a bit silly on a massive Z SLR, sort of like an ancient Kodak. ;-)

The Z 16-50mm is also the least expensive Nikon Z zoom lens and broken samples are available at relatively decent prices - which is perfect for evaluation and dissection. ;-) In fact, it may be the ONLY affordable sacrificial Nikkor Z lens likely to show up on eBay more frequently than total solar eclipses. Anything Nikon Z-related seems to be at least 4 times the cost of Nikon F gear. And many other Nikkor Z lenses approach $1,000 and beyond, even used.

Note that when mated to a full-frame (FX) camera, the coverage for this lens is DX: AFS-C or around 1x0.6 inches. The Z full frame cameras know that and will crop the photos auto-magically. So except for giant blowups, that may not even be noticed.

I have two samples of this lens:

Here is most of the dissection of ID #1: Nikon Z Nikkor DX 16-50mm 3.5-6.5 VR Zoom Lens Dissection Web Album.

For most of the photos on a white background, the setup used uniform cool white LED illumination on a piece of white paper. Where the broad area illumination and/or the white background poor rendition of glass optics or reflections from metal shims or other surfaces like the CPU PCB, the checkered yellow and white tablecloth ;-) was used and/or a combination of fluorescent and LED lamps for illumination. Post processing may include a bit of sharpening (which usually doesn't do much) and some minor brightness, contrast, and color adjustment where Auto White Balance didn't work so well. For those shot on the white paper which have little or no background evident, no AI was involved in its removal! ;-) And much of this was arbitrary, and please don't whine about the labeling. I know there are inconsistencies. Live with it. ;-)

Stay tuned for more.

Nikon Z DX Nikkor 50-250mm f/4.5-6.3 VR Zoom Lens

This is another mostly plastic lens made in China, but it gets generally good reviews and is relatively light weight. There is currently no repair manual available on-line.

I have a single sample of this lens:

Here is the start of the dissection: Nikon Z Nikkor DX 50-250mm 4.5-6.3 VR Zoom Lens Dissection Web Album.

Since no real problems with the optics were found after close inspection, the lens was put back together using the partially repaired Bayonet Mount Ring from the Z 24-50mm lens, below. And lo and behold, it actually takes very nice photos, but only when the Zoom Barrel is extended as far as it will go on this (broken) lens. (This was probably true originally but it wasn't tested with the Zoom Barrel at that setting.) Based on the EXIF data from a typical photo, that is 82 mm, which is consistent with the position of the Zoom Barrel. Anything shorter and the camera displays: "Before taking pictures, rotate the zoom ring to extend the lens" and/or will not focus at all. So that is probably where the other lens groups are stuck from the original trauma. Focus works reliably from infinity to a close distance of around two feet, similar to the spec at ~82 mm. The three sets of 1st Lens Cluster shims were NOT replaced because at least one was a different thickness. I didn't bother to keep track of that, assuming that this lens was never going back together. But the difference in thickness is extremely small which shouldn't affect field symmetry very much, and perhaps not detectably at all. But the missing shims would increase the close focus distance by a small amount. I think VR even works, though I can't totally confirm that as my VR test stand isn't set up for Z lenses, and there is also IBIS which might mask any effect of the in-lens VR. But it makes the normal VR sizzling sound when active. ;-) The last photo of the dissection shows the reassembled lens with the Zoom Ring set at around 83 mm just for show. Rotating the Zoom Ring has absolutely no effect on anything as the Zoom setting is monitored by an encoder on the Zoom Barrel itself, stuck at 83 mm, and the pegs that are needed to move the internal mechanism were sheared off.

It is now probably even good enough for government work as a Nikkor Z DX 83mm f/1:5? lens. ;-)

But what this means is that further dissection is on hold for now, at least until another sample is obtained. ;-) And the probability of that is rather small.

A fracture of one or more of the pegs that move the Zoom Barrels due to a mild trauma may be a common failure for the Z 50-250mm lens - There was another one on eBay listed as "For Parts or Not Working" with the photos showing a cracked Filter Ring but otherwise it appeared to be in very good condition. When the seller was asked what else was wrong, they replied: "It will not retract or extend any further. Something is locked up in the mechanism." Well we know what that is! ;( ;-) And yet another eBay listing with photos of a lens that looks pristine but no description of the problem and all the photos show the lens at the same zoom setting. Unfortunately, replacing those pegs is almost certainly not cost effective even for Nikon due to nearly total disassembly required. And that's assuming nothing else has been damaged by forcibly attempting to change zoom on the jammed lens.

Nikon Z DX Nikkor 12-28mm f/3.5-5.6 PZ VR Zoom Lens

There is a repair manual for this lens on the Nikon Self Service Repair Website. It has some decent diagrams showing general disassembly and reassembly, but nothing down to the inner core.

This lens is included here only because it is one of only two Nikon Z lenses currently available in 2025 that has power zoom (thus the "PZ"). The other one is the Nikkor Z 28-135mm f/4 PZ which is almost 10 times the cost of this lens so let's just say that I will probably not even be touching one in the foreseeable future. ;-) Both focus and zoom are "fly-by-wire" in that the Zoom and Focus barrels are optical encoders which send pulses to the lens's micro-brain, and thus they can be controlled remotely and nothing external moves. It is also unique among all the zoom lenses I have tested so far in that there is absolutely NO change in length regardless of focus or zoom settings. The electronically-controlled zoom does take some getting used to in that there is a small but noticeable lag between rotating the Zoom Barrel and the image changing. That's true of manual focus as well (including with AF-P lenses) but it's rarely used.

I have two samples:

I don't what the greater than 20,000 difference in SNs means. I doubt there were anything like 20,000 of these manufactured or sold. ;-) Perhaps direct from Nikon (#1 in Nikon box) versus from a reseller (#2 in unmarked beige box). They are physically and functionally identical.

Nikon Z Nikkor 24-50mm f/4-6.3 Zoom Lens

This is another mostly plastic lens made in China. While not super fast with a relatively limited zoom range, it gets generally good reviews. The format is FX (full frame) and it is fairly small and light, with a overall appearance similar to that of the Nikon Z DX Nikkor 16-50mm f/4-5.6 VR Zoom Lens above, like that one went on steroids. ;-) So it could be a handy lens to carry around. There is currently no repair manual available on-line. Note that this does NOT have VR, which at 50 mm isn't that much of a deficiency, especially if the camera has IBIS (In Body Image Stabilization).

I have a single sample of this lens:

Probably no more to come soon on this lens as it is no longer broken enough to be dissected. ;-)

Miscellaneous

Nikon DSLR Doesn't Recognize Memory Card

This may be specific to the D5x00 DSLRs when attempting to use a brand new SanDisk Ultra 32GB SDHC. The message is "This memory card Cannot be Used. Card is Damaged. Insert another card." Then nothing responds, even the configuration menus, so it cannot be formatted in-camera. And formatting it on a PC using either NTFS or FAT32 makes no difference. A Web search will return all sorts of suggestions. But the simplest is to format the card in a Canon camera. Really. ;-) The specific case here is a Nikon D5200 and Canon SX710 HS. This was not a fluke with a single card but happened on more than one occasion.

Nikon Electronic Flash Issues

WARNING: All electronic flashes using xenon lamps have an energy storage capacitor that can hold a high voltage charge for hours to days even with the camera off, the flash disabled, or the battery removed. The 330 V capacitor in a D70 still had more than 250 V on it after at least a day with no battery. Touching the wrong contacts can result in a shocking experience (though probably not a lethal one). But it can kill the camera if it ends up discharging through the electronics. This only matters if disassembling the camera for repair or curiosity and then mostly in areas relating directly to the flash or capacitor. It is not something the user of the camera needs to be concerned with unless the case is damaged, particularly in the areas of the flash or capacitor (whose location depends on the specific camera model). And with the flash cover removed (as might be required to repair one that doesn't pop up), both ends of the flashlamp are exposed. The risk is not necessarily between them as there is an IGBT or a similar electronic switch in series with one side to implement the energy conserving flash control, but between the live contact and other parts of the camera. And that can not only be shocking but kill the camera as well. Discharge the capacitor at the capacitor terminals using a power resistor - 10-15K recommended while monitoring with a DMM to below 1 V or so. Then short across them with clip leads and leave them there for awhile. (Capacitors can recover some charge on their own.) DO NOT just put a screwdriver blade across the terminals as there could be a rather dramatic flash-bang with collateral damage to the shorting tool and terminals. See the document: Electronic Flash Units and Strobe Lights for more details including safety precautions.

Nikon AF Lens Zoom and Focus Roughness

If you're used to the silky smooth operation of a classic Nikon lens like those for Nikon film SLRs, it will be a bitter disappointment to use a modern Nikon DSLR zoom lens. Lenses like the 50 mm f/1.4 "standard" lens or 43-86 f/3.5 zoom lens were works of art in comparison. They were mostly made of machined aluminum and well lubricated. Many samples 40+ years old still perform like new.

Modern lenses are much more sophisticated and no one would want to go back to the fully manual older ones, but silky-smooth operation is not one of their features. And it's easy to see why. Most of the moving parts are made of plastic and a zoom lens has many of them. For example, see Major Moving Parts of Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G VR Zoom Lens. These all move when changing zoom or focus. The three cylinders at the top of the photo reside nested and rotate or slide with respect to each-other with a large surface area in direct contact. The center one is made of anodized aluminum with precisely milled slots that determine the required movement of multiple lens groups with respect to each-other when zoom is adjusted; the other cylinders are formed or molded plastic. The straight slots in the upper-left (outer) cylinder guide those moving parts that must not rotate. Pegs or rollers (without ball bearings) restrict their movement to the AND of the slots in the upper left and the other cylinders, but also add friction. Some parts reverse direction as the Zoom Barrel is turned, adding additional friction/resistance at that point. It's all rather intricate and I bet Nikon has a really nifty CAD package for zoom lens mechanical design. ;-)

As an example of a common much larger lens, see the diagrams in Nikon AF-S DX Nikkor 18-200mm f/3.5-5.6G VR Zoom Lens showing Lens Group Positions at 18 and 200 mm. Lens Group 3 and the VR assembly move together, but those and all the others move relative to one-another and relative to the lens structure attached to the Nikon F mount.

Even on a brand new lens, there is detectable roughness and varying resistance over some parts of the zoom range. Over time, the lens will be exposed to dust, moisture, and contamination either from normal use or from being tossed in a storage bag, it gets worse as there are no real seals. And plastic is subject to wear. The good news is that for the most part, none of this makes any real difference in picture taking performance. That is, until the thing seizes up completely or falls apart. :( ;-)

But if the lens is dropped or whacked, parts like those pegs can get broken off or may dig into the tracks with varying degrees of damage. In minor cases, the roughness will just become worse but with enough trauma, major functions will stop working. When considering the purchase of a used lens, carefully check autofocus, manual focus, and vibration reduction, as well as for correct operation of the aperture at all zoom settings. Don't accept a lens where manual focus doesn't work reliably even with a discount (as I once did) because the seller said no one ever uses it. While that may be partially true, unreliable manual focus can be a symptom of more major problems. One thing that is often broken on used lenses though is the Lock button if there is one, used to secure the lens in a compact state for storage. The internal lip that the button engages is made of plastic and users often attempt to twist the Zoom Barrel without realizing it's locked, so that lip gets damaged and the button non longer works properly. That alone is probably not sufficient reason for rejecting a lens - but perhaps it may be leverage to negotiate a discount! While Lock may not work or work well, the end-stops for the Zoom Barrel should not be affected. But this should be confirmed as bad things may happen on some lenses if the Zoom Barrel is rotated beyond the normal range.

Mechanical versus Electronic Shutter Complexity

For all except camera geek types, this is probably just in the "that's interesting department". ;-) Mechanically-controlled shutters - both leaf and focal plane type - are designed along the lines of precision time-pieces with springs, gears, cogs, escapements, and levers that open and close the leaves or blinds. But whereas clocks are supposed to run at a fixed rate, shutters typically have 10 or more speeds. Electronically-controlled shutters use a pair of solenoids to determine the timing based on signals from a microcontroller. As an example, see: Comparison of Mechanical and Electronics Focal Plane Shutter Complexity. The Copal Square S shutter on the top is from a Nikon Nikkormat FTN 35 mm film SLR; the one on the bottom is from an older Nikon D80 DSLR. (The photos have been scaled so that they are approximately the same size independent of the FX and DX formats.) To fine tune the mechanical shutter requires the adjustment of the torque provided by some springs, the position of specific parts, and even the selection of slightly different parts based on actual timing measurements. And even then, the actual shutter speeds may only be accurate or repeatable to within ±10% on a good day. For the electronic shutter, it is just firmware code which could be optimized automatically after assembly. ;-) Shutters in other DLSRs where control of the sensor itself is NOT used to determine exposure at any speed would be similar. For those cameras where the sensor is used as the high speed shutter like the D70, they would be even simpler. In principle, there should be no need for any mechanical shutter in a DSLR or mirrorless camera but for practical reasons, this is rarely - of ever - the case. But point-and-shoot cameras generally do NOT have a mechanical shutter of any kind.

Copal Square S Focal Plane Shutter

The original Nikon F used a horizontally-moving focal plane shutter with fabric curtains. The fastest flash sync was 1/60th of a second. The Nikkormat FT/N use a vertically-moving Copal Square S focal plane shutter with metal "Venetian Blind" panels with 3 slats each. It can flash sync at down to 125th of a second. The Copal Square S shutter is an example of the state-of-the art in mechanical shutter design. It is described as a workhorse which really doesn't break, though as with any mechanical system, may require cleaning and lubrication after a half century or so. However, it is common to find these dating from the 1970s or earlier in perfect operating condition. At first glance, the mechanism might appear to be too complex to have ever been designed by humans. Think of a mechanical pocket watch with 11 speeds. But it evolved from or in parallel with leaf shutters that have similar timing requirements.

See the Web Album at: Copal Square S Focal Plane Shutter Mechanism. (The Web Album photos are scaled to fit within 1024x768 pixels but the full size originals have the name under the thumbnail with a ".jpg" added.) The first 4 photos are of a beat up Nikkormat FTN in various stages of disassembly starting with most of the pieces of the lens mount in place to revealing the Copal Square S shutter in situ. These are followed by closeups of another similar shutter. The primary difference between them is the use of a less expensive Nylon gear for the speed select compared to the highly polished brass one, and some slotted head screws in place of Philips head screws. Since there is no real stress on that gear, cheaper is just fine, thank you. ;-) My black dot on the white gear lines up with the post for the 1 second setting. In the interest of full disclosure, I have swapped the gear and screws to make the separate shutter mechanism more photogenic. And in the interest of expediency, the screws that secure the body parts have been left off. ;-)

Two manuals relating to Copal Square S Shutter repair are known to be available on the Web and hard copies may be purchased on eBay and elsewhere. Both Copal Square S Shutter Repair Manual and Copal Square S Shutter Repair Guide are interesting reads, but they may not enable you to be able to do much in the way of repair. The first one does have a 75 (!!) step procedure with diagrams for assembling a shutter. ;-) Aside from the intricate nature of these mechanisms, special jigs and instruments are required for some of the procedures. However, cleaning and lubrication of specific parts may be possible. This will involve the use of solvents like alcohol or naptha along with an ultrasonic cleaner if available, followed by lubricating specific bearing points and surfaces ONLY with the tiniest speck of special oil or grease as appropriate. A shotgun approach of simply sprayng it with degreaser and adding oil anywhere that looks appropriate will likely result in a nice paperweight. DO NOT even think about allowing WD40 or anything similar near a precision mechanical device like this! ;( ;-) A Web search will turn up suitable procedures but take them all with a grain of sand.

Control of the shutter bears similarity to that of mechanical leaf shutters, but it needs to determine the timing of the pair of blinds rather than opening and closing a set of leaves. For the Copal Square S There are three (3) regimes of timing:

And as a matter of interest, operation of the shutter in a fully mechanical SLR and specifically the Nikkormat is as follows:

  1. The film advance lever cocks the shutter via a rack gear at the bottom of the camera, cocks the mirror mechanism via a lever linked to the rack gear, and advances the shot counter.

  2. Pressing the shutter button triggers the mirror to flip up.

  3. When the mirror reaches the fully up position, it triggers the actual shutter to open.

  4. Once the shutter has closed, the mirror returns to the down position.

For the "B" setting, everything is the same except that a tab on the shutter linkage prevents the shutter from closing until the button is released. The actual shutter speed is probably forced to 1/1000th second so closing would not be delayed no matter how quickly the button is released. The Nikkormat doesn't have a "T" setting, but for that operation would be similar but there would be a simple escapement that would require the button to be pressed a second time to close the shutter.

Optical Materials used in Nikon Lenses

Until I started to dig deeper into the construction of these lenses, I had always assumed they used individually ground and polished glass optical elements. Sure, inexpensive pocket cameras have always used plastic optics, but Nikon-branded DSLR lenses? Really? ;-)

It turns out that a variety of types of glass and plastic may be used and the optical elements may be either ground and polished or molded. Sometimes the lens specifications will include some information on the material thought probably NOT the fabrication method if the Marketing Department thinks it will help sales. For example, Extremely low Dispersion Glass (ED Glass) and aspheric are pointed out in the info for lenses like the AF-S DX Nikkor 18-55mm or 18-200mm. They probably won't state anything if plastic. ;-) If not specified, the material can be any either common optical glass (BK7, crown, flint, etc.) or plastic. Aspheric elements are probably molded since individually grinding and polishing them would be cost prohibitive.

There is no easy way to determine the material and fabrication method non-destructively (or at least without some damage) on an intact lens as they appear identical. But even if the lens is disassembled into the individual lens groups it's a challenge. Glass is several times more dense than plastic so the weight of a lens group can be a tip-off, especially for the larger ones. Ground and polished lenses will generally have frosted edges while molded ones will have smooth lips and perhaps even tabs. But the overall appearance of the individual lens elements is essentially identical in terms of surface finish and AR-coating.

Diagnosing Nikkor AF-S Autofocus Problems

Nikkor AF-S lenses have a reputation for reliability problems. However, this may be undeserved at least in my experience. I've acquired some AF-S lenses in fairly dreadful cosmetic condition that worked just fine. And where there were focus problems, they have not been due to the SWM or related parts. However, these are more complex than the later AF-P lenses, both mechanically and electronically. The symptoms may be a total failure to focus, movement of the focus more likely in or out, or erratic behavior.

Some possible causes are:

Nikon Silent Wave Motor (SWM) Disassembly

The following applies to the compact SWMs like those used in the AF-S DX 18-55 mm "kit" lenses. (The full diameter SWMs in those like the AF-S DX Nikkor 18-70mm f/3.5-4.5 ED IF lens are secured by the overall lens focus mechanism.)

Since there are no user seriveable parts inside ;-), this is probably only justified to attempt cleaning of a gummed up SWM, or for curiosity.

Take some photos to record the arrangement of parts.

The motor is held together with an itty-bitty C-clip at the non-gear end. That needs to be popped off carefully so as to not have it go pinging across the room to be lost forever. You won't find a replacement in your junk box or Home Depot!

Then the shaft with spring and gear will slide out from the disk that mates with the fingers of the ultrasonic transducers. The mating surfaces must be clean and free of any lubrications. It's metal-metal contact. If it is gummed up, carefully clean with alcohol or acetone avoiding getting aolvent anywhere other than the mating surfaces. Reassemble in reverse order.

Lithium Ion Camera Battery CPR

WARNING WARNING WARNING: Perform this stunt at your own risk! And please read up on what a Web search returns for something along the lines of: "Lithium ion camera battery zero volts". And we will not be responsible for damage to your ego, anatomy, or the Universe that may result. Having said that, the procedures described below should be pretty safe, though they may not be fool-proof or safe from fools. ;-)

The following applies to the type of lithium ion battery packs found in Nikon (and other) digital cameras. Don't try this on your Tesla. ;-)

CAUTION: This remedy ONLY applies to a battery pack whose terminal voltage reads exactly 0 V. It CANNOT be used with individual cells that still have a measurable voltage, individual cells that lack a protection circuit. or a battery pack where one or more cells are dead and the terminal voltage is non-zero but never reaches its rated voltage even after an extended time on a compatible charger.

When the type of lithium ion battery pack found in digital cameras discharges below its useful minimum voltage, not from normal use but usually from a prolonged period of inactivity like YEARS, the internal Battery Protection Module (BPM) kicks in so the pack's output voltage may measure zero volts even though internally there is still some charge remaining on the individual cells. This is to prevent the battery from being discharged further by connecting it to a load which can result in permanent damage. Normally, a low voltage cutoff circuit in the camera (or other device) will shut off before the BPM activates so there will still be a non-zero battery terminal voltage. But if the BPM has disabled the output entirely, smart chargers may also refuse to recharge the pack unless they have a 0V activation feature.

The solution is to apply a current-limited voltage to the battery terminals to reset the protection circuit. Plus-to-plus, minus-to-minus, just like jump-starting a car. But unlike a jump, this is simply to reset the BPM, not to actually charge the battery. That should be left to the appropriate charger. A variable DC power supply with voltage and current readouts is best but an inexpensive easy to construct alternative power supply can also be used. More below. As the voltage is increased starting from 0 V, initially there will be little or no current, but once the BPM has reset, the battery will draw current and it will then retain the voltage if the input is reduced or removed. If successful, the measured output voltage will then be 2/3rds or more of the rated voltage. The battery can then be put on a compatible charger and should respond normally. Some so-called "OV" chargers will deal with the reset auto-magically, but probably not the those from Nikon.

Having said all that, this is not rocket science. ;-) A simple BPM reset device can be constructed from almost any DC power supply with an output that is current limited to order of the battery's mA-hr rating/hr. So for a pack rated at 7.4 V, 1,000 mA-hr, a 12 VDC wall adapter with a 10-15 ohm power resistor for current limiting should be acceptable. But don't omit the resistor - there may be a non-resettable fuse inside the pack which could blow from even momentary excessive current. And there is a risk of fire and explosion from REALLY high current. Thus, don't try this using a car battery or your arc welder as the power supply. ;( ;-) And if the pack doesn't recover decent voltage after a couple of shots, it may be too far gone.

CPR was successful on several EN-EL9 batteries that came with a low mileage Nikon D40X DSLR which had probably been sitting around unused for 15 years or more. The EN-EL9 have 2 cells and is rated at 7.4 V, 1,000 mA-hr (for the original version, up to 1,080 mA-hr for the EN-EL9a and EN-EL9e). They initially all played totally dead with a terminal voltage of exactly 0.00 V and this did not change even overnight on the Nikon MH-23 charger. An unregulated variable DC power supply with a built-in voltmeter was used to increase the voltage across the battery terminals just to the point where it started drawing current indicating that the BPM had reset. That point was easily found with this unregulated power supply since then the voltage dropped and changed more sluggishly with respect to the voltage adjust knob due to the load. The batteries were then put on the MH-23 charger. After 15 minutes or less, each had enough juice a Nikon D40X to power on. Full charge was reached in around an hour. Only time and use will reveal if they will hold a charge and have decent capacity.


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