Dez
Bodger Extraordinaire
I have been looking at tele lenses for my nice new (to me) S2 and I was appalled to see how much they cost, much more than the equivalent Leica lens. I have heard all about the discrepancy between Contax and Nikon mounts, and that one can probably get away with a Contax mount wide angle lens, but not for the longer ones. There were all sorts of cautions, but never anything very quantitative. So I have been doing some experiments with an old Ukranian (Russian?) Jupiter 11 135 lens to see what is involved in making it fit. There are a few things to do, but they aren't too difficult.
First, undo the three little screws that hold the ring at the very back of the lens. This will need to be ground down slightly, or it will probably scratch the front of your precious Nikon. I put a piece of #320 emery paper on a flat surface and rubbed the back surface around in circles to plane it down a bit. If you sand it down carefully until brass shows all around the raised area, which is about 2/3 of the circumference, you should be fine. Clean the ring off carefully before you put it back on.
The next step is optional- I decided to go for it because the blackened brass focusing coupler on my lens is tight in the Nikon focusing mount, which must be a tiny bit smaller than that of a Contax or Kiev. I took the lens apart, following the excellent instructions to be had on the Kiev Survival site, at http://www3.telus.net/public/rpnchbck/Jupiter-11 dismantle.html
I put the focusing coupler in a lathe and ever so carefully filed a couple thou off the slightly raised ring just back of the coupling tabs. Take just enough off to keep it from jamming in your Nikon. The alternative is to push a little harder than you are comfortable with when mounting the lens.
Next, Exakta comes to the rescue; to be more precise, an Exakta reflex focusing hood. These are the greatest tools ever for determining accurate focus. Mount the lens, open it up all the way, set the camera on T, and remove the back. The Exakta focusing hood, complete with magnifier, when pushed right up against the film rails makes a superb critical focus device. I used it to verify that the lens was focusing accurately at infinity. There is a lot of variation in these lenses, as quality control was evidently considered an evil tool of the imperialist West, but in this case I got lucky, and the focus was bang on at infinity. If it isn't, you need to fiddle with the shims under the screw-in optical unit. I tried the same thing with a Kiev 9 85mm lens and gave up at this point, as I couldn't figure out where to get a thinner shim that I needed.:bang:
Using the same rig, I made measurements at different focusing distances comparing the rangefinder setting to the actual focus at the focal plane. I found for my lens that at a 3m focusing distance, you need to rack out the lens so that the indicated distance is put against the f8 depth-of-field line. For a distance of 1.6m, to the f16 line. I would not be at all surprised to find that other examples of this lens would need slightly different corrections.
So there you are. It's a bit inconvenient, and I suspect the lens quality isn't quite in the same league as the Nikkor 135, but it's cheap, and I guess the same thing could be said of me!
Cheers,
Dez
First, undo the three little screws that hold the ring at the very back of the lens. This will need to be ground down slightly, or it will probably scratch the front of your precious Nikon. I put a piece of #320 emery paper on a flat surface and rubbed the back surface around in circles to plane it down a bit. If you sand it down carefully until brass shows all around the raised area, which is about 2/3 of the circumference, you should be fine. Clean the ring off carefully before you put it back on.
The next step is optional- I decided to go for it because the blackened brass focusing coupler on my lens is tight in the Nikon focusing mount, which must be a tiny bit smaller than that of a Contax or Kiev. I took the lens apart, following the excellent instructions to be had on the Kiev Survival site, at http://www3.telus.net/public/rpnchbck/Jupiter-11 dismantle.html
I put the focusing coupler in a lathe and ever so carefully filed a couple thou off the slightly raised ring just back of the coupling tabs. Take just enough off to keep it from jamming in your Nikon. The alternative is to push a little harder than you are comfortable with when mounting the lens.
Next, Exakta comes to the rescue; to be more precise, an Exakta reflex focusing hood. These are the greatest tools ever for determining accurate focus. Mount the lens, open it up all the way, set the camera on T, and remove the back. The Exakta focusing hood, complete with magnifier, when pushed right up against the film rails makes a superb critical focus device. I used it to verify that the lens was focusing accurately at infinity. There is a lot of variation in these lenses, as quality control was evidently considered an evil tool of the imperialist West, but in this case I got lucky, and the focus was bang on at infinity. If it isn't, you need to fiddle with the shims under the screw-in optical unit. I tried the same thing with a Kiev 9 85mm lens and gave up at this point, as I couldn't figure out where to get a thinner shim that I needed.:bang:
Using the same rig, I made measurements at different focusing distances comparing the rangefinder setting to the actual focus at the focal plane. I found for my lens that at a 3m focusing distance, you need to rack out the lens so that the indicated distance is put against the f8 depth-of-field line. For a distance of 1.6m, to the f16 line. I would not be at all surprised to find that other examples of this lens would need slightly different corrections.
So there you are. It's a bit inconvenient, and I suspect the lens quality isn't quite in the same league as the Nikkor 135, but it's cheap, and I guess the same thing could be said of me!
Cheers,
Dez
