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1957 KMZ Jupiter-8 2/50 M39 on NEX-3
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PostPosted: Mon Aug 05, 2013 12:03 am    Post subject: Reply with quote
Attila wrote:
Quite unbeliavable J3 is favorite lens for a Leica owner, nice to hear Smile


I know quite a few people using J-3's and J-8's on Leica film and digital cameras. I just sold a J-8 for use on a Leica M-E going to the UK, and a J-3 for use on an M type 240. I will start a similar thread for the J-3.


PostPosted: Mon Aug 05, 2013 12:11 am    Post subject: Reply with quote
Look forward it, thank you!


PostPosted: Mon Aug 05, 2013 1:28 am    Post subject: Reply with quote
BrianS wrote:
The J-8M is a simplified formula Sonnar- 5 elements in 3 groups, the M39 version stuck with the 1-3-2 (6 elements in 3 groups) throughout the production run. I also believe the Contax/Kiev version is not as sharp as the M39 version. KMZ produced the M39 J-8 to the end, as far as I know. I have one that is modified for 0.65m close focus on the Leica, a real-hack that worked. Consisted of intentionally misthreading the helical and then turning the distance scale and focus ring to line up.


The J8 isn't simplified, they copied the Sonnar design, same with the J3. The J8 has 6 elements and the J3 has 7, same as the Sonnars. The difference between the J8 and J8M is simply the addition of clickstops to the M version. You can study the various variants of the J8 and J3 here:

http://sovietcams.com/index.php?-483601546

I don't think there's any difference in sharpness between Contax/Kiev and M39 versions, I have two of each, all 1950s red p ones and I can't find any variation in sharpness.

Jupiter-8 on left, Jupiter-3 on right:



Sonnar 2/50 on left, Sonnar 1.5/50 on right:



There are some minor differences between the Sonnars and Jupiters as the Russians had to do some recalculations once they ran out of Zeiss glass - the early postwar Russian lenses are assembled from war booty components.


PostPosted: Mon Aug 05, 2013 10:48 am    Post subject: Reply with quote
I've read that the J-8M modified the optical formula by combining the middle triplet into a doublet, combining two of the 3 elements. The glass elements of the J-8M are not interchangeable with the M39 version, I tried. The optics are larger diameter. I have a J-8M at home, I'll tear it down. This is not uncommon: I have a "bizarre" wartime 5cm F1.5 in Contax mount that had a doublet in place of the rear triplet.
http://www.rangefinderforum.com/forums/archive/index.php/t-24907.html


PostPosted: Mon Aug 05, 2013 10:52 am    Post subject: Reply with quote
Good stuff guys and new (for me) info, so keep it coming!


PostPosted: Mon Aug 05, 2013 6:56 pm    Post subject: Reply with quote
kds315* wrote:
Good stuff guys and new (for me) info, so keep it coming!


The advantage of having lots of spare parts.

I took apart a 1967 J-8 and a 1968 J-8M.

The J-8 is the traditional 1-3-2, 6 element in 3 group Sonnar. I have used a rear doublet from an early J-8 to repair a pre-war Zeiss Sonnar 5c F2, perfect fit. The Zeiss Sonnar 5cm F2 has the front element and front triplet pressed into a metal housing, the J-8 has compatible glass- but different fixtures.

The J-8M is modified, as stated in the old RFF discussion. It is a 1-2-2, 5 element in 3 group design. The middle triplet has been replaced by a doublet. The groups have larger diameter than the J-8 optics The shapes are very different. This makes a lot of sense: the middle triplet of a Sonnar is two negative elements filled in with glass of a low refractive index to basically eliminate two air/glass interfaces. Use a new glass, fold in the design.







J-8 on the left, J-8M on the right. The rear element is longer, and has different curvature. The J-8M is a new design, different from the J-8. I wonder why there was never an LTM version of it? Maybe I will make one.


PostPosted: Tue Aug 06, 2013 11:33 am    Post subject: Reply with quote
Cheers Brian, that's good to know, and explains why the J8M is slightly less good than the J8.

I find it very strange that they introduced the J8M for Kiev but not for Fed/Zorki. Strange because the Kiev was for pros and advanced amateurs and the Fed/Zorki was more for the masses.

BTW, if you don't have a Helios-103, you should grab one, they are only in Kiev/Contax mount, but the optical block is a direct fit into an I-61 M39 barrel. It's a copy of the Summicron and absolutely superb.


PostPosted: Tue Aug 06, 2013 5:13 pm    Post subject: Reply with quote
I've used Helios-103's and the Menopta 53/1.8 for a long time. I bought several Menopta's, shimmed 4 of them for Nikon S-Mount. Also converted a Helios-103 to Leica mount using a close-focus helical for a Summar.

I might try converting this J-8M to a Leica mount, I think the aperture ring from the J-8 and variable retaining ring will exchange.


PostPosted: Tue Aug 06, 2013 5:22 pm    Post subject: Reply with quote
I don't know the Menopta, is it the same lens as the H-103?

Another one to look out for is the Vega-1 2.1/50 cine lens, it was designed as a rf lens and the optical block fits an I-61 barrel to, I'm about to remount mine into an I-61 barrel. It has a 5 element simplified planar/double-gauss schema similar to a Biometar or Xenotar.


PostPosted: Tue Aug 06, 2013 6:26 pm    Post subject: Reply with quote
The Menopta is a "rebranded" Helios-103, but made almost 10 years later- in the mid and early 90s. It was made for export, in limited numbers. The machining seemed to have higher tolerances- again, made in limited numbers. I picked up 7 of them as new-old-stock a few years ago. Shimmed them for Nikon RF's.
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