Nikon Camera and Lens Information and Repair

Version 1.34 (26-Jan-23)

Copyright © 1994-2023
Samuel M. Goldwasser
--- All Rights Reserved ---

For contact info, please see the Sci.Electronics.Repair FAQ Email Links Page.


Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied:
  1. This notice is included in its entirety at the beginning.
  2. There is no charge except to cover the costs of copying.



Table of Contents

  • Specific Nikon Lenses

  • Miscellaneous



  • Back to Audio and Misc Repair FAQ Table of Contents.

    Preface

    Author and Copyright

    Author: Samuel M. Goldwasser

    For contact info, please see the Sci.Electronics.Repair FAQ Email Links Page.

    Copyright © 1994-2022
    All Rights Reserved

    Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied:

    1. This notice is included in its entirety at the beginning.
    2. There is no charge except to cover the costs of copying.

    DISCLAIMER

    Although working on cameras is generally less risky than dealing with microwave ovens, TVs, and computer monitors, there is one component in every camera with an electronic flash - even the least expensive throw-away variety - that is potentially lethal. Specifically, it is the energy storage capacito. And of course even more so for separate electronic flash units or "speed lights" with their higher energy. This may charge up as soon as power is turned regardless of whether flash is called for, and may retain a dangerous charge for hours or days. If working inside a camera or flash unit, on one that has had its case damaged exposing internal parts, it is essential that you read, understand, and follow all safety guidelines contained in this document and in the document: Safety Guidelines for High Voltage and/or Line Powered Equipment.

    If there is no electronic flash, the greatest risk is torn flesh from sharp sheet metal or gear teeth. ;-)

    We will not be responsible for damage to equipment, your ego, county wide power outages, spontaneously generated mini (or larger) black holes, planetary disruptions, or personal injury or worse that may result from the use of this material.



  • Back to Audio and Misc Repair FAQ Table of Contents.

    Introduction

    The is random information and some repair notes on various Nikon cameras and lenses I've worked on. Some of this used to be in the Audio FAQ. Originally it was supposed to be only about Digital SLRs (DSLRs) and their lenses, but it will be morphing into covering some aspects of fully mechanical cameras with at most an exposure meter. The latter are just such beautiful examples of what can be done well without high tech electronics.

    Recommended Tools

    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.

    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:

    1. ID #1 (SN: 24105203): The lens that came with my D5600.

    2. ID #2 (SN: None): The well worn lens was used for the original disassembly but without enough attention to detail to call it a dissection. This only had a non-working lock button and broken bayonet mount. It did take pictures. I don't know if the SN fell off or was missing from the start. I should not have taken it to bits but waited for a certifiably dead AF-P lens with good bayonet mount to transplant. Reassembly is not going to happen. Oh well.

    3. ID #3 (SN: 22091057): Lock doesn't work but otherwise functional...

    4. ID #4 (SN: 21672615): Fully funtional..

    5. ID #5 (SN: 24816754): Lock doesn't work but otherwise functional..

    6. ID #6 (SN: 20566871): Lock doesn't work but otherwise functional...

    7. ID #7 (SN: 23321760): Fully functional placed in original box from AF-P #5.

    Finding a certifiably broken (defines 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. ;-) As can be seen, the lock doesn't lock on most 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". :)

    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. Do NOT do this if the future of the Universe depends on getting the thing back together in a functioning condition. ;-)

    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 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 these 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.

    More coming soon.

    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 two samples of this lens and am expecting a third, all in very good cosmetic condition but with problems:

  • ID #1 (SN: 527838):This lens is not quite able to autofocus - it requires help but appears to try moving in the correct direction. After an extended period of attempting it, the bottom appeared to be getting warm.

    At first I assumed that the SWM itself was gummed up and unable to move. But the problem turned out to be that one of phases of the SWM drive signal was not present. Phase A (arbitrary designation) was nice and strong at around 240 V p-p but Phase B was dead. This was determined with the use of my 55-200mm VR SWM Test Rig, which does away with the Fixed Shell and brings out the two SWM drive phase signals and ground soldered to conveniently located pads on the SWM flex cable. So these and others can be probed in situ while on a camera. See the dissection photos. There was also something strange about this lens as the grounding wire to the spring contact was disconnected at the contact-end and the insulation over most of its length was missing and the conductors were frazzled looking like a horses tail. ;-( It was replaced with the light gray wire in the photo. Whether that was the cause or result of the bad SWM drive - or a total coinidence - is not known. Testing the SMT transistors marked K1YSD next to the ferrite components with a DMM reveals that there is a short across a pair of leads for the lower one. According to an SMD marking code database, these are Samsung KSA3265-Y SOT-23 NPN transistors: 30 V, 800 mA, 200 mW, which would sounds about right EXCEPT that this is on the OUTPUT side of the transformer which can have more than 200 V on it! So perhaps it isn't a KSA3265-Y. Since I don't believe in coincidences, I wonder if the stray ground wire shorted to something and blew the transistor. But assuming the part number is correct, the Fairchild/ON Semi KSC3265 appears to be an acceptable substitute. Now to justify a Digikey order for a 26 cent part. ;-)

    Even if replacing the transistor returns the lens to perfect working condition, it may never be destined to be buttoned up. Having a partially naked lens could prove handy. ;-) And there is another similar lens coming which probably has a good POW PCB so it may be swapped, which would be much simpler assuming these are not matched to a specific SWM.

    In fact, the apparently shorted transistor was a red herring. It turns out that these are not bipolar transistors but MOSFETs based on the Nikon patents. And stray voltage on the gate was fooling the multimeter into thinking there was a short. When that was discharged, the SO23 parts on both POW PCBs behaved the same.

    So swapping the POW PCB made no difference. One phase was still dead. The next step was to check the SWM. The dead phase was an almost dead short at the SWM. But swapping the SWM also made no difference. As a last resort, the CPU PCB was swapped and three was the charm. ;-) With the good SWM, original POW PCB, and swapped CPU PCB, the lens sprang to life. Autofocus now works. About those coincidences, it's possible I blew the original CPU PCB because the cable between it and the POW PCB was installed slightly angled and perhaps making improper contact when the POW PCB was first swapped. That causing the same problem is unlikely but if not, one must accept that both the SWM and CPU PCB were bad. VR doesn't appear to activate though even with the VR switch ON. Oh well, can't have everything.

    With the brain transplant, any parameters stored in its memory that were optimized for the lens from which the CPU PCB originated are now incorrect. How much difference that may make is yet to be determined.

    This is now my "Visible" lens with its innards exposed. ;-)

    An attempt was made to locate the short but it provded to be very well disguised even after complete disassembly of the SWM and under high magnification. So when subtlety doesn't work, try brute force: Discharging a capacitor across the "short" cleared it But nothing exploded, so its location is still a mystery. The SWM may get tested eventually. It was disassembled for the photo shoot, cleaned, and put back together.

  • ID #2 (SN: 896820):This one was stuck at 55 mm. The zoom bareel moved slightly but hit a hard stop. The alignment of the Back Shell and Zoom Ring was offset very slightly, which provided a clue.

    In fact, the cause turned out to be a crack in the Fixed Shell with a small piece hitting a spring pressure strip and getting stuck. Repair of a small plastic piece is not realistic so it was removed along with the metal strip, whose function appears to be to add some resistance so zoom doesn't move so easily that the lens changes the zoom setting on its own. However, with that done the lens appears to work just fine, thank you. Exactly how that Fixed Shell cracked is not at all clear. There is no sign of trauma to the lens. The Fixed Shell minus the offending piece is shown in the dissection. It is at the upper right of the Fixed_Shell_Front1 photo.

    AF and VR seem OK now.

  • ID #3 (SN: 3263342):Autofocus hunts and doesn't lock. Unless the problem turns out to be something trivial like a flex cable that became unplugged, the plan is to use the SWM and possibly the SWM PCB from this lens to repair ID #1. It appears as though transplanting the SWM is simply a matter of 4 screws and one plug-in flex cable. Of course, getting inside to access the SWM is a real treat, but after the third time should not be that bad.

    Initial finding on ID #3 is that the zoom value returned by the Zoom Encoder was incorrect beyond around 100 mm - 105 mm read back as 100 mm, 135 mm read back as 100 mm, and 200 mm read back as 145 mm. These data were determined from the EXIF data for a series of test shots. One common cause is contamination on the encoder strip. Unfortunately (or fortunately) depending on one's point of view, this appears to have corrected itself temporarily at least. Perhaps the contamination was rubbed off. This may be wishful thinking but for the time being it works so don't fix it. ;-)

    However, AF works well but VR doesn't seem to activate.

  • ID #4 (SN: 836632600): The back shell and its mounting posts are broken off, Camera Contacts cable torn, and Bayonet Mount broken. The SWM and CPU PCB were used to revive ID #1 so there may be no excuse not to use this for the detailed dissection. ;-)

    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 Parts 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 light weight 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.

    1. ID #1 (SN: 20229424): Very good condition except that the Camera Contact strip was a bit pushed in on one end and the aperture prong didn't spring back as it should. While the lens was recognized by the camera, AF was dead. However, removing the inner ring and loosening and then readjusting the position of the Camera Contact strip seems to have cured everything. ;-) How that caused it to spring to life it not clear as the offset seemed very minor. But because the lens now works, it is not destined for dissection, only portraits, sorry. ;-)

    2. ID #2 (SN 20583677): The main problem appears to be that while the Lock button works for lock, the stop at the 55 mm-end is broken. So zooming in can easily overshoot. It is also somewhat tight which could be partly to blame for someone being overzealous and breaking the plastic stop. Or perhaps the broken bit is stuck inside somewhere.

    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 Parts 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.

    1. ID #1 (SN: US2748346): Decent cosmetic condition and fully functional.

    2. ID #2 (SN: US3578427): Intact but will not focus at all because of broken prong on 2nd lens group housing. See below.

    3. ID #3 (SN: Unknown): Partially disassembled with back shell and Bayonet mount parts missing. Reassembled with parts from ID #2 but there must be a problem with the zoom tachometer or encoder. It tends to oscillate around the correct focus but sometimes locks.

    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. 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 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 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 the camera.

    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.

    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. :( ;-)

    1. ID #1 (SN: 46156305): Near perfect cosmetic and operational condition...

    2. ID #2 (SN: 46140507): Very good cosmetic condition but manual focus does not work if zoomed out beyond 100 mm or so and autofocus may be temperamental for related reasons..

    3. ID #3 (SN: US46070728): Very good to excellent cosmetically. At first AF was erratic but the lens was still cold from being dropped off outside. After a warming up and a bit of exercise, it seems to focus reliably. VR seems OK but that will be confirmed once the VR Test Rig is fully operational. So this lens doesn't appear destined for dissection. Grrrr. ;-)

    4. ID #4 (SN: US46026627): Very good cosmetic condition but with some of the gold paint on the lettering worn off. Excellet functional condition with smooth zoom, working AF and VR..

    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/3.5-6.3G ED VR Zoom Lens

    This is believed to have the highest zoom ratio - over 16:1 - of any Nikon DX lens. There are at least 2 versions of the 18-300mm VR lens. This is the newer and lighter one 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.

    I have not found a repair manual or even an exploded diagram for this lens, though it appears to be generally similar to the 18-200mm VR and 28-300mm VR versions for which there are manuals. If anyone has one for this lens, please contact me via the Sci.Electronics.Repair FAQ Email Links Page.

    I purchased a certifiably broken sample and it was used for my photos below. But not inside yet. The main issue is that VR does not do anything. That could be as simple as a bad switch or wire that came off. This is a well used lens but focus (A and M) works and while zoom is a bit hard to move at times, nothing appears really damaged, though there is a serious nick in the lens hood mount ring (visible in some of the photos) so it has experienced some trauma.

    See the Nikon AF-S DX Nikkor 18-300mm f/3.5-6.3G VR Zoom Lens Dissection Web Album.

    This lens does take photos as long as one is careful to avoid camera shake, so reducing it to parts may not happen for a while. But the back was opened to check for obvious problems. The flex cables were all secure and the VR switch was tested so an easy fix is unlikely. However, if removing the bayonet and related parts, make sure to record the precise location of the brass shims - which I of course neglected to do initially. This lens has 2 and they are not identical so the orientation and also which one is on top may matter, though it's not clear why. And when reinstalling the aperture tang, take care that it goes into the correct location in the aperture actuator. Unlike many other lenses, it's a rectangular hole on this one, not just cup or U-shaped lever. It can slip in outside the hole and while it may appear to work when first installed, when the Inner Ring is put in place, it will jam. Other than that, reassembly is quite straightforward. There are only 4 types of screws and where they go should be intuitively obvious. ;-) But some are quite small so losing them is too easy and would be bad. ;-( And don't overtighten them!

    As they say: "If it ain't broke, don't fix it.". After going inside, two things changed: First, the image through the viewfinder "jerks" initially when the camera is turned on and the shutter is pressed, but only when VR is on. However, VR doesn't do anything else. This indicates that VR is being powered but is jamming to one side. I don't think VR did anything when first testing the lens. So perhaps that's an improvement. ;-) Second, autofocus stopped working reliably. I could have sworn it wasn't like that initially. Sometimes it would lock but usually it would either get stuck at one end of its range, or continue hunting back and forth around the optimal focus unless very close, in which case it might lock. So the back parts were removed again and it was discovered that one of the brushes in the Focus Encoder wasn't contacting the encoder strip. I have no idea how that could have occurred during the excursion inside as it's safely recessed. But once the brush was "adjusted", autofocus is back in shape. The microbrain had no idea where focus was at any give time so it didn't know what to do. Poor thing. ;-)

    I also reseated all the internal flex cables at the same time as dealing with the focus issue but that didn't make any positive difference to VR.

    However, now the lens produces 4-1/2 "clunks" about 1/2 second apart when the camera is powered up and sometimes when it's powered down regardless of whether VR is on, independent of zoom and focus settings, but only with autofocus enabled. They sound like they are coming from the vicinity of the VR assembly but don't appear to do anything to the image in the viewfinder. The count of 4 is digitally precise and the behavior is totally repeatable. Go figure.

    Having said all that, the lens takes great photos and therefore I have no plans to go inside again. If only it could be filled with helium so to weigh less. And the previous version was even heavier so I'm searching for a sample. ;-)

    Stay tuned just in case.

    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 but for practical reasons, this is apparently rarely the case. 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

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



  • Back to Nikon Digital Camera and Lens Information and Repair FAQ Table of Contents.

    -- end V1.34 --