Thanks for this sweet mod. Funny thing with my attempt (using D90 and N70) was that disconnecting P11_3 and P11_2 (to set the chip as a 70-210/f4 and kill the autofocus errors of the default configuration)resulted in an aperture range of f/3.8-25. Also, for some reason, on my chip, grounding P11_3 (to set the chip as a 50/1.8) didn’t work and still shows f/1 on the D90.

Anyway, sticking with my f/3.8-25 configuration and autofocus is sharp when used with a 50/1.8D.

By the way, I ran across the source for your CPU pinout diagram: http://photo.net/nikon-camera-forum/00956N

I have done the modification and after a few tests I have put it back the way it was.

I used the modified version of TC-16A on a D700 and with a 50mm f1.2.

First of all, the modification is by no means an easy task. Do only attempt with the right equipment and only if you feel confident with it.

In my case, even though I was being super careful I managed to loose one of the springs. Luckily I found one to replace it in an old printer.

After the mod the lens does not communicate the aperture to the camera. This generates an error which can be solved by changing a setting in the D700 to allow the camera shot and control the aperture using aperture ring. This lets you shot but the aperture is still not read by the camera so forget about the light metering. It’s back to hand held light meter in your hand or guessing the exposure. Far from ideal.

Now, the pseudo autofocus; yep, it worked, kind of. When it finished the mod and tried for the first time I was quite impressed it worked at all! It’s very cool to see a manual lens auto focusing but…. it was way out!. I get the idea of pseudo autofocus, approximate manually and then use it, but still. It was obviously out when compared to my focusing by eye manually. I was testing this on f1.2 so a tiny bit out is enough to ruin any image with such a shallow deph of field.

From the other comments, I gather that the results can vary depending on the type of lens and camera. It could also be that there is a fault with my TC-16A but I don’t think so.

In my case it is back to the way it was. At least I can use the converter in manual focus which is fine for me.

Thanks for all the effort explaining the process. Pity it didn’t work out for me.

Cheers,

I like the partial autofocus, you still get the feeling of MF, together with precise AF in the end. On the D300 it even works for birds in flight !

Thank you Oliver for all !

Thanks for all these precious info. This is so rare that one can do DIY on photographic equipment !

I plan to use the TC-16A with 300/2.8 AI and D300.
Should I better set the pins as a 50/1.8 (7 stops as the 300/2.8), or as a 210mm (6 stops only, but closer focal length) ?
As I plan to use the lens ring for aperture control, and do not often close at f/22, I should probably do the latter, am I right ?

On the other hand, is similar focal length important ? I mean, the TC-16 AF mechanics are probably very different compared to the 70-210, so is it of real help for the body focus calculations ?

Thanks in advance.

Vertigo.
(PS : I happen to have a recent AF 50/1.8 D. Can I use it in any way for completing the TC-16A modification ?)

That’s why there is no “at f/22″ “at “f/32″ setting, only an “at 5 stops from max aperture” or 6 or 7… and it’s those settings that the camera expects, and you’ll need to set the pins 112 and 113 to match the aperture RANGE of the lens you want to use.

It’s the same for the D300 and the D700 but depends on the lens you put on the TC.

Now of course, there is still the workaround that I used in the main description under “D200 Specifics” (before the findings described in the comments):

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).

then you don’t need to care about the aperture range (which will be 1 for your Reflex lens – so you won’t find a matching pin setting anyway), and instead you can choose the pin setting according to the focal length, to help the camera determine focus. That way you don’t need to modify your T-adapter either.
I don’t know enough about optics to tell you which setting to choose – I’d try the 70-210/4 setting, but the reflex lens might behave completely different and another setting would be better. With the 70-210 setting, you might want to set the focal length to as long as possible (210mm) using pin P103 P102 P101 P100 settings described in comment # 49 by Murphy

Regarding item 9 – thanks for pointing me back at it, but the finer points still escaped me. Walter (point 34) seems to be saying saying that with P112 & 113 high his manual 400mm f/4 reads the aperture correctly to f/22 – I’d be very happy with that!

Following your suggestion and moving the aperture index ring manually beyond the test lens’ minimum aperture does indeed stop the FEE error, but only when the D700 aperture ring is at a certain position (approximately at the “F” of AF TELECONVERTER”). It’s a start!

The MF lens I’m using for test purposes (an old Tokina 35-70 f/3.5-22) cannot take the F ring that far over because it only stops down to f/22. So I wonder if I am right in assuming that’s because the minimum aperture of the 70-210 is f/32 and so the D700 thinks there’s a problem? Forcing the aperture ring over another millimetre or so seems to make the D700 work, metering and exposing more or less correctly in low light. Perhaps I’m getting somewhere.

So, I looked at the three lens specs in 9) and took P113 low – 50mm f/1.8, max aperture f/22? Guess again; the aperture ring needs to be taken even further round because (I guess) the f/1.8 stops down to about two-thirds of a pinhole.

So, back to the soldering iron and take P112 low instead. Success! Stopping down to f/22 now works, and the camera takes pictures! *does little dance of joy*

I plan to use the TC-16a with a T-mount 500mm reflex lens nominally at f/8, plus some other T-mount MF optics of varying focal lengths.
So I guess the next thing will be to make up a T-ring that’ll force the aperture ring to f/22 and then manually dial up the exposure settings. Not too much of a burden, because I don’t intend to use the AF for complex, variable lighting conditions or
fast-moving subjects.

(So why use AF? Unfortunately I have a heavily astigmatic focusing eye and even with good spectacles my manual focus technique is best described as hit and miss).

So, Oliver – have I guessed correctly about what’s going on here? And is it basically down to the fact that the D700 is such a darn fine camera with sensors and compatibility galore that it’s just that little bit harder to fool than some of its earlier brethren?

I should perhaps point out that my background is in electronics and communications, rather than photography. I take, and publish, a number of quite boring engineering photos in any given year but for me the camera is just a tool to get a recognisable image into a magazine – rather like a word processor is a tool for capturing the text that surrounds the image. That said, I do quite enjoy fooling around and amusing myself with my cameras, and am a sucker for available-light stuff.

G.

the FEE error comes up when the Aperture index tab doesn’t correspond to the min aperture defined by the lens type defined by the setting of pins P113 and P112. Read comment number 9 again for the details.

basically it depends on which lens you put on the TC, and it’s aperture range. you have to make sure it’s the same number of stops as the lens that the TC pretends to be (pin 112 and 113 setting).
Before you go and solder anything, try moving the aperture index tab on the D700 with your fingers, or with forcepts or something. And if that works, try using a lens with the correct number of stops.

I am an experienced electronics constructor; fine soldering doesn’t scare me.