Jupiter 8M in LTM?

[Austintatious]

A while back I picked up an Industar 61LD with a Keiv mount attached to a NEX adapter from Grandseller @ Ebay. It is decent quality and works well. Now I can use my Jupiter 8M and Helios 103 along with the I61LD on my NEX 6 and my A7II. Happy camper 😀

Industar 61LD converted to Kiev mount & adapter by Carlos Yashinon, on Flickr

 

[rfaspen]

I bought the converted lens off Ebay for $50- all work done, and perfectly shimmed.

The person used a Chrome focus mount. So many Canon 50mm lenses get etched glass- he had a couple of mounts bought cheap several years ago.

Photo(s) of the beast? I'd like to get an idea what was done. At the very least, I'd like to see a cool and potentially unique lens. Always fun.

I probably would have forked out $50 for a converted J8M in Canon barrel if done nicely and correctly focusing, etc. Yes...., I think I would...

 

[former member]

One of the best $50 ever spent on a lens.

The maker of this lens did a fair bit of machining, the optics rotate with the focus. He has to basically remove the inner portion of the Canon lens to do this.

The J-8M is good, it is the revised design. The original J-8M has a middle triplet that where the surface between the second and third element is flat, and the third element has a smaller radius. I suspect that centering the elements in this group were a problem. This later J-8M has a middle triplet more like a standard J-8, but bigger diameter.

 

[raid]

Your lens looks great, Brian.

 

[former member]

1960s J-8M middle triplet-

I refused to believe this was a triplet as there were no seams, even after soaking in acetone.

KMZ J-8 on the left, 1960s J-8M on the right.



So I did some destructive testing.



And I think the flat surface and dissimilar radius of the 2nd and third elements is a reason why performance of the several J-8M's from the 60s that I've owned was awful. This is a design where the production people should have asked the optical engineers "how the hell are we going to align it?"

 

[former member]

The the old Optical Engineer retired, somebody threw out his ugly baby, and then did it right.

This is the 1970s J-8M.







The J-8M from the 70s on the left, KMZ J-8 on the right.

My 1970s J-8M converted to Leica mount is very good. I have it in the line-up to test against the new Bertele Sonnar when it arrives.