Schneider Tele-Xenar 70mm f/2.2

[dickb]

A long time ago I got this lens, thinking it would be fun to use on my Sony NEX 5N






As you can see, this version of the lens has some drawbacks for regular mirrorless camera use, as it is designed with remote video camera control in mind. It had a cable for remote aperture and focus control, and a spotfilter, the dark spot you see in the middle of the optics. This spot is designed to get a more abrupt gradient in light transmitted when you close the aperture, and allow the aperture to be fully closed, both apparently benefits for the system it was designed for.

I didn't like the mirror lens type doughnut bokeh and the annoying cable, so I first tried to sell it and then left it in its styrofoam for many years with the idea that one day I would convert it into a more practical lens for me. Unlike several other such projects, I actually did start to do so. The cable could be removed quite easily and unlike some other lenses of this type, removing the spotfilter wasn't that difficult - although I did manage to mess up the aperture, with the blades falling out. Putting those back is a project I think I will postpone for a long time, I like shooting wide open anyway...




Taken with Sony NEX 5N (APS-C) and the lens's original C mount.

As you can see, there is considerable vignetting. In the next photo, taken with my full frame Sony A7, it is even more pronounced, as to be expected:




So I took off the rear of the barrel, with the C mount itself, and freelensed it with some m42 tubes in front of my A7:



This seems to indicate that the C mount itself causes vignetting (when the lens is used on cameras with far larger sensors than the ones intended to be used with this version of the lens). Anyway, next step will be fabricating an M42 mount onto this lens, so it will work better with my cameras.

To be continued...

[kds315*]

[memetph]

Your first shot is showing a nice mixture of mechanical and optical vigneting .