By Oliver Perialis

I bought a TC-16A, even though I knew that it doesn’t work on my D100 or the D200 I was planning to get. But I thought I’ll take it anyway, since I don’t have any usable converter and this one is pretty cheap compared to the other ones. I figured I’ll try to find out why it doesn’t work, since I couldn’t even find any useful information on that.


First thing I noticed is the different pin layout on the TC-16A compared to all my other AF-lenses. I’ll call these pins 1 X 3 4 5 X 7 (as seen on the picture of the TC, where the X’s stand for empty spaces).
(above=TC-16A, here=Sigma 8mm) pins here: 1 X X 4 5 6 7
So I openened the Converter to have a look where these pins connect to. There is a CPU inside, just like in any AF-lens.
This is the front of the circuit print. It features a NEC D7554G502 “CPU” as its main component. Just for your information: the circuit print continues on the left all the way to the connectors: the top circuit path (top left pin of the IC) connects to pin 1 the next lower one (on left of the top resistor) to pin 3, then the next one down pin 4, then pin 5, and the very bottom circuit path (bottom right pin of the IC) connects to pin 7.
This is an IC I found which seems to be compatible. Turn it anticlockwise by 90 degrees to have it in the same orientation as on the picture above (front view).
On the back all the connections are visible.
  • lens mount Pin 1 (top right circuit path on the picture) connects to IC Pin 20 (Vss) as well as 19 and 18
  • Pin 3 (via resistor) to IC Pin 1 and 5 (P00/INT0 and P80)
  • Pin 4 (via resistor) to IC Pin 4 (P03/SI)
  • Pin 5 (via resistor) to IC Pin 3 (P02/SO)
  • Pin 7 to IC Pin 10 (Vdd)
I didn’t want to open any of my AF lenses, to see where the difference was, but I didn’t need to after I found the results of someone having done exactly that (I could no longer find the source where I found this, so I cannot mention it here):
[edit] Tazman (comment 75) found the source: A very interesting thread by “Ro Ro” on [/edit]

And what do you know!? – its basically identical! Except for one difference, which is exactly what I was hoping for…

Pin 3 (on the TC) which was out of place anyway is connected to the IC in the same way that Pin 6 (on the AF lens) is connected!

Research result: JUST MOVE PIN 3 to the (unused) position 6… that’s it!!!


A quick note to begin with: Most the feedback I get about this page is that the people tried this modification and lost one of the small golden springs. So please be careful with those – I don’t know where to get any spares!!

This by the way is what the circuit print looks like at the other end.
So I drilled a hole (1.4mm for those who want to know, or just slightly wider – the metal contact that needs to fit through is exactly 1.4mm wide) in position 6, and made sure the metal contact fits well, and moves easily. I drilled it by hand, NOT with a Dremel or so, but just by rolling the drillbit between my thumb and index finger. It took a little longer, but gave me a much cleaner result.
Luckily Nikon didn’t save every milligram of plastic they could and there is already a notch in which the metal contact can slide, without touching the other contacts.
Now I soldered a little wire onto the little spring to electrically connect it to its old position on the circuit print.
Then put everything back together…
Oops, one more problem… The contact on the circuit print for Pin 5 is a little too wide and our new pin 6 would touch it as well, which is not good…
So I just covered that side of the contact with a little bit of cello-tape (I know this is not perfect, but the best Idea I could think of to make the whole process more or less reversible).
NOW put everything back together..
And finished!!! :-)

D100 specifics
(probably more cameras, eg D70, D50, D80, F100, F80, etc)

Just one more thing…
(I got an F E.E Error on my D100)
A little something (don’t know what it’s called) that moves a switch and this tells the D100 (and other cameras) that the aperture ring has been turned to minimum aperture (and so enables controlling all apertures via the camera). If you cut a piece of hard plastic (I used an old PC CPU fan) into the shape above, it fits really well (in a very good position) in between the Converter and the little cover for the “CPU compartment”.
Now we’re really done!! – That’s it!
This is how it looks on my 500mm f/8 Reflex Lens

One more note: the Aperture the TC transmits to the Camera is always f1.0, as minimum and maximum aperture. So it is not possible to change the aperture at all. My 500mm (which I mainly bought this converter for) has a fixed aperture, so it’s not quite so bad, but it would be nice if this were different.

D200 specifics
(probably applies to D1 and D2 series, D300 and D3 as well as F4, F5 F6)

Since the D200 has AI coupling, there is no physical switch like for the D100. Therefore, the little plastic thingy will not be necessary. However, somehow it didn’t work anyway (same F E.E error). The Trick is: go to CSM (Custom Setting Menu) under f: “Controls”, position f5: “Command Dials”. There, under “Aperture Settings” choose “Aperture Ring”. This means you can’t control the Aperture via the subcommand dial anymore (so you’ll want to switch it back when you put a normal AF-D lens on the camera again).

Tools used

  • Philips No.000 Screwdriver
  • 1.4mm drillbit
  • a very fine-tipped soldering iron
  • a dremel (only for shaping the little plastic piece)

Parts used

  • 1cm of very thin, insulated wire
  • a small piece of hard (nonbrittle) plastic – got mine from an old PC CPU-fan


OK, basically it works, but the use is very limited. It’s limited to the maximum aperture of the lens attached. On the D100 that’s it. Nothing you can do about it. On the D200 it only meters for maximum aperture, even if you set it to a different aperture. If you do want to use a different aperture, you’ll just have to dial in some exposure compensation.

Future Ideas

To overcome the aforementioned limitations, I believe the only solution would be to replace the chip with one that has a range of apertures, and not just “f1” for both minimum and maximum aptertures (this is what imposes the limitations).


I will not be held responsible for any problems caused directly or indirectly by following the above instructions/information. Use at your own risk!

244 thoughts on “Modify TC-16A

  1. I have a Nikon D1x. Will these mods allow my D1x to work with (some) non AF lenss in AF mode? I understand the prefocus and focus range limitations. I have a lovely Sigma 300F2.8 I have been dying to use this way. Thanks

  2. hi, I modify the tc but with the 180 ed ais the diafram are blocked and there is a F1 message, and in p mode on the camera(d700 d300) fe error, you can explain me the modify on the tc body, for correct manual f number control? grazie thanks leo

  3. @John

    I don’t have a D800. But the 500 P with a modified TC-16A works very well on a D700 and I can’t see any reason why it wouldn’t work on the D800.

    Until I found this blog, I have used the TC-17EII on the 500 P. I have not made any systematic tests, but to me the ability to get the focus tack on gives much more IQ to the image than any optical differences between the TC-16 and the TC-17.

    However, I find that the TC-16E on the 500P gives a substantial vignetting on full frame.

    I find that the 500 P and TC-16A is able to give stunning images that leaves nothing to be desired compared to my 300mm 2.8 VR with the TC-17E – provided it is supported by something like a Gitzo series 3 and a gimbal head and provided proper long lens techniques are used and provided the atmospheric and light conditions etc. are OK.

    But this is a subjective judgement on how it works for me!

  4. Soren.
    Thank you for the informative reply. You made a very valid point by saying that tack sharp superceeds any optical difference in the other teleconverters. I have a Jobu Black Widow gimbal with an alum Induro 413 tripod rated at 44lbs. It seems very rigid but I am a neophyte with regard to the Nikon 500mm f4 P and its abilities. I also am anxious to implement the req’d long lens technique.

    I was informed recently by one who modifies the TC-16A, that there could be a conflict with the D800 but he was unsure. There were very few D800s in use at that time for anyone to offer any input.

    Thanks again for your response! John

  5. Hi! Thanks for the TC-16 mod!
    I have not read ALL the comments, so I don’t know if someone else already have suggested this; but it strikes me that a smart thing to do would be to dispose of the CPU in the TC-16 altogether! And make “female” contacts on the “lens-end” of the TC-16, an d just pass those trough! Thus you would always get the right focal-length & aperture- reading on the camera and in EXIF. You may have to dial in +1EV to correct for the 1EV loss, but I think the meter would take care of that anyhow…

  6. I tried my modified TC 16A on a D800 and to my surprise it did not work, i.e. It did not focus correctly unlike my D200.

  7. Hi all,I try th e modified TC16A with my Nikon D300 and 300mmf4 MFand 400mmf2.8MF and work very well! I am satisfied.Quick focusing on 400 and 300mm lens .Perfect exposure.New life for my MF lens.

  8. Can you suggest the correct pin disconnections/earthings for a Nikon 400 F3.5 AIS ?

    It has 6 stops from F3.5 to F22

    Any other tips? Its going on a D800 and I would like to continue to use the command dial on the camera to set aperture. Can I leave the ring set to F22 as I do now?



  9. Hi Oliver, I would like to thank you for your time publishing the above and sharing your knowledge..i have done my modification on last 2 years..i very happy with the combination TC16A with lens Nikkor 300mm f2.8 Ais & Nikkor 500mm f4P.. for result pls feel free to visit here

  10. Hi. I’d just like to say thanks for all the information here, and to suggest a different approach to moving the connecting pin on the teleconverter. Instead of soldering direct to one of the tiny springs, I added a new contact to the ribbon PCB. The procedure, with picture, is outlined in this thread on

    If done carefully it means that the converter can be easily put back to its original pin configuration and there’s no risk of damaging a spring.

    If you want to reproduce the picture of the mod here I can email a copy of it to you.

    Regards “Joe”

  11. Dear Oliver

    I’ve just joined the army of enthusiasts who have taken on the modification of the TC-16A thanks to your very helpful work here, (plus a few extra bits from Jaco and André Mostert). Thank you for all the effort you and others have put in to sharing advice and experience on these pages. I am now the proud owner of an autofocus 500mm (now 800mm) Reflex-Nikkor on my D90. As my interest is astrophotography, the autofocus will be used almost exclusively to find infinity, as the 500mm reflex has no hard stop!

    Best wishes

  12. …and in case anyone is wondering, YES! on a D90 it does focus on a bright star at 500mm f/8 (now 800mm f/12.8).


  13. First off , Thank you Oliver for taking the time and effort to not only experiment with the TC-16a but share with us everything, and secondly to keep this post alive since 2009. I have had the wonderful Nikkor 500mm f/4 P since 2006 (my fave Birding lens)and have often thought how nice it’d be to have that smidgen of focus ability as my eyes are growing older and I have now moved into bifocals :( . . with that said you can imagine my feeling surprised and a bit happy at finding your post regarding the Mods to the TC-16a. I ordered one this morning and have read the entire blog, although not seeing anyone using a D7000 I am sure it will probably work as it is much like the D700 and D300 so the mods should work well. I will use the plastic part from a donor lens with the appropriate holes for the pins and lift the two pins. When done I will do some test and report back on your site. Thank you for sharing, and also all those whom have contributed . .
    Tim S.

  14. hi Oliver, how about a YouTube vid to help us less hands on types with all the fiddly bits

  15. @Nippa: coming soon, some time early next year! I won’t have time for that before CES in January.

  16. @oliver p. That would be awesome! I’m going to attempt it over Xmas but would love to have the video to fall back on. Thanks

  17. @ Oliver, again Thank you for your article, I was successful and now my D7000 can use the TC-16a (pins 112-113 lifted from contacts for correct readout in meta data when using the 500mm P lens & 70-210m f/4 zoom) Might I suggest you you condense all the pertinent data concerning the mod to one page, this would save one from having to scan through the comments for relative info. One item that might also be mentioned is the additional wiring might cause one to have to notch the back of the pin plate so it will fit when sandwiched back together. . . anyway several hours and the fruits of my labor where a success. hope everyone that tries this meets with success, but be careful, it is not something a neophyte will want to do. All things fun have their challenges.
    A picture using the Nikon D7000, TC-16a and Nikkor M/F 70-210 f/4 can be found here.


  18. This has been an amazing and entertaining read, thank you for doing this.

    Question: Will this work on this combo?

    Nikon D800
    Nikon 400mm f3.5 Ai-S lens

    If so, what is involved? Thanks.

  19. Hello Oliver. Many, many thanks to you and the contributions of Soren Klostergaard and Jaco Mostert. Today I moved the pin. Instead of soldering a wire, I used the copper tape idea to bridge contact 3 to six. I have not yet unsoldered P11_2 and P11_3 but will try this later. this is the result:

    Nikon D700 + 500mm AI-S P + TC-16a. CHEERS! TsaiProject

  20. @TsaiProject: That’s a great idea with the copper tape!

  21. Wow what an interesting read, about the possible modifications to the (humble) TC-16A. Rather above my ‘not-so nimble fingers’. My wanted use for the TC-16A, was to continue using the combination of it, with a Nikkor 300 f/2.8 manual lens. It works well enough on my F 4 camera body, but wanted to use it on my D70, or Fuji S5Pro. I would not want to tinker with the converter, and lose the film body functions, but was hoping that ‘Nikon’ had brought out a digital body version.
    Thanks for allowing me to read about your expertise in the modifications carried out.
    Regards Paul.

  22. I am thinking of getting this for my D800/500mm f/4 P IF-ED combination, but see that some people have reported difficulties on the D800.

    Is that confirmed, that the modified TC-16A does not work with the D800?

  23. My modified TC-16A (with pin-swap and P112-113 cut) is working fine with D800E and 500mm/F4P

  24. This mod works on my D800 and Super Cosina 100-500 f/5.6 – 8. Meta data reports correct aperture, but the aperture is manual now. Not really a problem for me. Set up 210mm per post #49.
    Special bonus: The lens with mounted TC still fits inside the lens case. Hah!

  25. I just purchased a TC 16a on eBay in ‘excellent’ original condition after reading much about how to get limited AF functionality from the TC 16a. – Thanks to all contributors.

    I have a beautiful Nikon 600mm f4 ED IF Ais lens serial # 2010xx – later design, but manual focus and my failing eyesight has made it almost impossible for me to use.

    I have D2h, D300, and D800 bodies that I would like to use the lens with, and I would like ‘advice’ on how to proceed – I am very comfortable with fine pitch soldering and de-soldering, as well as dealing with ‘small parts’ , i.e. springs.

    I also have a ‘for parts’ disassembled Nikon 70-210 f4 – 5.6 lens with CPU for parts.

    Appreciate any and all detailed advice on the use of the three bodies with the TC 16a, I understand the TC 16a and D2H will work together ‘as received’ (assuming the TC 16a is as original per eBay listing) so I will give it a try to get the knack of the TC 16a and verify it can focus with the 600mm F4 IED IF AiS lens.

    But for D300 and D800 bodies I needto make a decision for modification(s) as I understand – the bodoes will work with modifications of pin 3 and lifting legs of CPU –

    Can the CPU and pin connector from 7-0-210 help, or will it be more of a problem since there will be no grey code inputs?

    Is there a CPU for a 600mm f4?

    Thank you in advance for any and all replies.

  26. Hi Guys – Well, I finally had a go at this conversion, and (boy am I mad at myself) lost one of the contact pins!

    If anyone has a TC-16A for parts, or a spare pin or two and would be willing to trade or sell them, PLEASE contact me. Thanks!

    Dave Honey

  27. Tim S –
    Which version 70-210mm F/4 lens are you using? My reason for asking is that I have an E-Series Nikon version, and have read where the TC-16A will damage the lens if I try to mount it. Camera body is a D7000.

  28. @ David H, firstly, sorry for not periodically checking back at this site, I have been busy shooting pix all 2013 (did a 365 project), in response to your question, I am using an AI version which has AF, it is the f/4.5 ~ 5.6 Push Pull AF version (non-D). My primary goal with this conversion was to use it with a 500 f/4 P which it works without problem. Sounds like you lost a pin. for you and the group: You can buy old lenses through KEH.COM rated Ugly and scavenge them for parts, it is less expensive, then you have lenses and parts you can take apart to play with if you are a DIYer.
    Those using the D7000 do not forget you have to go into the menu and change the Aperture control from [sub command dial] to [Aperture ring]for the TC to operate, failing to do so will not let the TC work.

    again: Special thanks to Oliver and everyone else who have contributed to his web page.
    here are some helpful links for lens info
    Asian website in english very good site on older lenses and accessories

    An older website with great info on exotic nikkor lenses

    Ken Rockwells website (great reviews/info on lenses and camera bodies)

    and if you are interested in contacting me or see what I am up to you can browse my blog

    Thanks everyone who contributed here, hope this site stays alive as there will always be someone tinkering!
    Tim S

  29. Thanks to everyone for this work. I have a contribution. I am using the modded 16A on my 500P F4 and a D600. I moved the contacts and cut pins 112 and 113. I discovered that if you move the aperture sensing ring on the lens side (as opposed to camera side) of the TC counter clockwise (away from the aperture sensing stop block on the 500P), there is a point at which the FEE error disappears when the camera is set to control the aperture form the command dial. On the TC body, this corresponds to the “TEL” of the Telconverter printed on the body. I used a small piece of plastic between the TC body and the sensing ring to hold the lever at this position (so it never springs back).

    This yields FULL control from the camera and no need to set the camera to control the aperture from the aperture dial. Full PSAM and dead on metering. Exif still reports 210mm F4; but if this bothers you you can change the custom lens data to 800mm F7.

    I know this is long after the main interest, but others may rediscover the manual lenses and want to add some AF to them now that we have an “affordable” full sensor body.

  30. @D.Clark: I believe what you found is the same as setting the aperture ring of the 500P to F/32, is it not? This is (and has been) the main advantage of using the secondary modification (that’s only described in the comments so far) – disconnecting pins 112 and 113.
    If you want to control the Aperture of any non-G lens from the camera rather than the aperture ring, you must always have the ring set to minimum aperture, such as F/32. If you don’t , the lens is mechanically limited, and the exposure can be off, if the camera is trying to use a smaller aperture than the one the aperture ring would be set to. This is why the camera won’t allow this, and will display the FEE Error until you set the Aperture ring to min. Aperture.
    When you add the TC-16A, this minimum Aperture setting is still needed, but it doesn’t always correspond to the minimum aperture setting of the lens. On some lenses it’s one stop below minimum aperture (such as F/22 if the min. Aperture is F/32) or on some it might be one stop or so more.

    The important thing is that you must find that setting, and leave the aperture ring at that setting at all times, or you’ll get the FEE error. With the secondary modification (Pins 112 and 113), and finding the right position for the aperture ring, you’ll get full matrix metering and PASM options, and the ability to control the aperture from the command dials.


  31. Oliver,

    I think that is precisely what happened. I guess I have the 16A locked to where the F32 stop would be if the 500P did stop down to F32. Since I only use it with this lens, I have no qualms about locking it in this position. At 50 meters focus distance this tc/lens combo yields an 800mm F7 with about 6 to 8 meters of focus range; good enough for many wildlife situations.

    THANK YOU for publishing this info and keeping the this page up.



  32. Thanks for your great DIY instruction and helped lot of people like mw on tight budget.
    I have D90 and 300mm f2.8 manual focus lens (1986 model) i would like to but this converter and diy my self is it focus faster and do i need to manually focus close to subject and then camera focus sharply right
    Thanks in advance

  33. Dear mr.Perialis I remove pin 112and 113 and the PCB is death! I connect the circuit of Tamron zoom 28/200 3,5/5,6.Exif:focal lengt is 155mm and max.aperture is 5,6.TC 16a works very well except MTO 500f8.Little problem is to install the circuit!Thanks giorgio botta

  34. Dear Olivier,

    Many, many thanks, my 300 2.8 IF ED (first series, i’m too poor to afford anything else) became again sharper than ever!!! As expected, EXIF 145mm, and all the rest works perfect.

    I would recommend for the connection just to bond a custom cut of very thin copper, because to pass an isolated wire from pos 3 to 6 is a challenge, especially to close back the pin holder in its slot. For the 112-113 story, to unsold is also a challenge, I would recommend to avoid losing time to simply cut the two legs.

    Anyway, super trick I recommend to any TC16 owner, it took me in total 2 1/2 hours. Once tested, you will never want to come back to original.


  35. Dear mr.Oliver Eureka!I installed the circuit tamron 28/200 in a plastic box of 5x5x1 cm.pasted on a hot shoe.Thanks giorgio

  36. Thx Oliver for your information. I modified my TC-16A with change pin 3 to pin 6 location, and cut 112/113 on the chip. It works well on my D700 as well as D200. Especially, my old 55mm micro-nikkor lens becomes an auto lens with right exposure after using the modified TC-16A..

    Agian, thanks.

  37. I have just acquired a modified TC-16a. It works fine on my D1x. It does not work at all on my D7100. No AF at all. Any ideas where I should look to start debugging the problem?

  38. Hi all, first of all thank you very much for the work you have done and shared. Recently acquired TC 16A and I will use a Tamron SP 300mm 2.8 lens on a Nikon D300s, which recommend making me apart from the modification of position of pin 6 ?. Would need to explain to me if I do something else with connections cpu. Thank you very much, greetings to all from Argentina !.

  39. […] 2.Конвертер не поддерживает электронику современных камер. Конвертер работает с камерами до Nikon D2H и старше по возрасту. Для современных камер требуется простейшая перепайка, с которой справится любой. И конвертер начинает работать на Nikon D700, D300 и моложе по возрасту камерах. Здесь можно посмотреть подробную схему перепайки конв… […]

  40. Hi mr Oliver,
    I put circuit zoom nikon 35/80 into TC 16A because is flexible.Exif 50mm f3.5.It is very fast and I don’t have the external box whit vetronite circuit of tamron 28/200.Thank you very much for genial idea to modify TC 16a

  41. What an amazing thread. A career 30-year-pro…but had never heard of such a thing. Oliver, whoever you are, you’re famous now. I believe all of the “modified” TC-16s on ebay are a result of your Out of the Box thinking. I have no desire or the skill to DIY – that’s what You guys apparently do in your sleep. I’m going to Buy It Now for around $200, already modified. If my 500 f4 P becomes an autofocus lens I will be thoroughly speechless. Thanks everyone!

  42. Hi all,
    Oliver, thanks for the amazing thread!I bought an unmodified tc-16a and tried to modify it, but got stuck.While trying to put it back together, had it tough due using a little bigger wire.Then the soldering on the circuit print fell together with the copper place on position 3.Now all I have is this (picture below).Any sudgestions how to make it work?
    Plus, I cant find the cpu.
    Thanks in advance for any comments!

  43. Hello can someone publish one or two pictures of the real chip with the already cut pin112 and 113 ? Because i’m not sure what are the pins to cut. With a real picture it will be safer to do it, otherwise there is the risk to cut the wrong pins. One or more pictures are useful i think. Please help. Thank you

  44. @dilom: Oh-oh. You have a problem. Your options are: a) scratch the soldermask off the trace (the very very thin line of which there are 5 in parallel). it’s made of copper and you can solder a wire directly onto there. It will require some serious soldering skill to get it right. b) run a wire along the same path all the way down to the CPU, and solder it on there (onto the resistor).

    @juliaan: Here you go: P113 and P112 are the 2nd and 3rd pin of the top row (right above the “NEC” text on the chip) I usually don’t cut them, but rather de-solder them and bend them up, but it’s much easier to cut them (fairly close the the chip)

  45. Hello Oliver, thank you, i succesfully did the full mod thanks to your suggestion! If someone needs a picture of the cut leg of the pin let me know and i will make it, but your picture is very clear. The 3rd step is to mod the chip to have 210mm, but is there a benefit other than pure exif? thank you again for your wonderful web page

  46. I am unsure how much it does, but the focal length can influence how the camera tries to focus. It could be that Nikon only categorises focal lengths (super wide, wide, normal, tele), but it could also be that it distinguishes more finely, and therefore getting as close to your used focal length as you can, could be desirable. Apart from a little extra work, there is no reason not to do it. :-)

  47. A friend of mine fixed the damage on the tc-16a and got it working.I tested it with my manualfocus lenses today – the 50mm f1,4 AI, 100mm f2,8 E series and the very old 80-200 f4,5.The last one was the best imo, although all showed some frontfocus, which got better but a little bit stayed even at AF finetune on +20.I will try it with the 500mm P tomorrow and see how its working for birds in flight.

  48. hello all.
    I did modify my TC-16 5 yeas ago, and it worked fine. but I also must say that I haven’t not used it since. maybe once or twice.
    maybe not related to this mod, but I purchased a tamron 300 2.8, af that needs the chip replaced to work on the newer bodies. so I have been looking at that mod for a while and refreshing my memory with the info on this site. any ideas?

    anyway. back to this mod. I found another TC 16a and also got a broken 35-70 to just replace the cpu and contact instead of fiddling with the soldering. anyone used this replacement?

    another question; why should we match the lens max aperture when with this TC we loose 1 1/3 stop?
    a 2.8 will turn into a 4.5 theoretically that should lead to underexposed photos.
    however last week I used the TC-16 with a Nikon 180 2.8 cant say they were underexposed.

    I don’t know how the new TC with cpu in them deal with this.

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