TC-16A teleconverter on D700?

Discussion in 'Nikon' started by mihut_ionescu, Oct 31, 2012.

  1. I just bought a Tokin 300mm f2.8 manual focus and I found a Nikon TC-16A teleconverter for sale. It would be really nice to get that final AF capability after focusing on the subject. I own a Nikon D700 and I've searched the web to see if this teleconverter will autofocus on this body. I found contradicting results, some said it worked, others said they had to modify it. Did anyone here use this teleconverter *unmodified* on a D700?
     
  2. Unfortunately Mihut, the TC-16A doesn't work with the D700 without modification. There's no AF at all with this converter unless you physically move one of the contact pins. I have a D700 and bought my TC-16A new in about 1990, so I can definitely say that this combo does not work without modification.
    I've been meaning to do the mod on this converter for a few months, but haven't yet got round to it. After looking at the existing webpages showing how to modify the thing (here & here), I have a few ideas on how the job could be made easier, but I'll keep them to myself until i've actually tried it!
    P.S. You don't need the "AF stud" addition with a D700.
     
  3. Modification definitely does work (and is necessary) with the D700 - I followed the foolography instructions. It's much easier to access the board from one side than the other if you want to try fixing the aperture reporting (I forget which, but if you're having to dismantle half the teleconverter to get at it, try the other side), but I believe moving the pin is all that's necessary to get the autofocus to work - it's been a while since I did mine (and I think the aperture is now playing up again, though it still autofocuses). Be careful not to over-drill so the pin sits right - mine isn't quite central, due to my incompetence, although the result seems to work okay. The centre is respectably sharp, and it makes my 500 f/4 AI-P significantly more useful on the D700, though the corners aren't so hot. On a D800, there's a significant performance loss with this combination, but I've yet to give it a thorough test and some AF fine-tuning might help.
     
  4. Andrew, I was never impressed with the optical performance of my TC-16A, even on film. Vignetting is pretty awful at anything approaching a wide aperture, and contrast and sharpness ain't too great either. Once you're over the novelty of converting an MF lens to AF (partially), you're left with a below average converter that's beaten on IQ by almost any cheap 3rd party 1.7x TC. And that's probably why I haven't yet raised the enthusiasm to modify mine.
     
  5. Too bad someone has not taken the optics out of the TC14E and transplanted them into the TC16A so that those corners are better. I had the TC16A for a while and on a few lenses it was fine, but on most it really was not very good off center unless you stopped it way down.
     
  6. I found the TC-16A to be awesome on my D2X (no modification required) with my 200/2 AI and 400/2.8 AIS. Of course I would not have noticed any vignetting if there was any. I found it to be optically equal to the TC-14E and TC-14B.
     
  7. Right! This thread has finally given me the nudge I needed to get around to modifying my TC-16A. After all, the thing was just lying about near useless anyway.
    The picture below shows my variation on the mod. I thought that soldering direct to the gold-plated spring, as recommended on the "foolography" site, was a bit fiddly and potentially destructive. Instead I added a new contact to the ribbon PCB as shown. I did this by first lifting a gold-plated edge contact off an old ISA computer card. I used a sharp craft knife blade to "scrape" one corner of the contact up and peel it off - watch your fingers with this! Luckily, the contact came off clean, was just the right width and a little longer than needed. You should be left with what looks like a small rectangle of gold-leaf. Actually it'll be a thin strip of copper with gold plating on one side.
    Having got my new contact, I next soldered a short length (~20mm) of the thinnest connecting wire I could find to one end of it. Then it was fixed to the converter PCB using double-sided tape. You can just about see the tape in the picture. The tape serves double duty as an adhesive and insulator to prevent the new contact shorting to the adjacent one.
    Finally the other end of the connecting wire was soldered to the converter's ribbon PCB. You have to be quick with this, as the solder runs very readily over the gold plating. The joint isn't quite as small and neat as I'd have liked, but it serves the purpose.
    Reassembly is pretty much as described by Foolography, but make sure the contact springs don't creep out of line and short. Mine did, and required a disassembly and realignment!
    All that remains now is to work on the CPU connections to sort out the aperture coupling. I'm wondering if it's going to be worth the bother?
    00az8L-501911584.jpg
     
  8. The TC-16A was a special TC made to auto-focus manual lenses on the Nikon F501. It had a transistional purpose and it was never really intended for wider use. Because of this it has various limitations and restrictions associated with its use. In any case, its optical performance is certainly not up there with the rest of the Nikon TC range. Given that you have a manual focus lens they would be a better choice.
    Another option would be to get a the Tamron SP AF 1.4 TC. I have this and it is great with my Nikon 180. It should work well with your Tokina lens and it is definitely compatible with the D700.
     
  9. It is really sad that Nikon would not improve upon the TC-16A...it would give a new lease of life to the old manual focus lenses and offer a cheaper alternative to people like myself who can't afford the big gun telephotos out there. :(
    Avi
     

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