Looks like a decent lens, however I would avoid shooting it in high contrast situations since it produces a lot of lateral CA. Not sure about sphero chromatism? Haven't tested it for that.

I believe this is the lens comparison that has the carl zeiss jena lens.

http://forum.mflenses.com/communist-135mm-sonnars-comparison-t33719.html

That thread does include Zeiss jena 135mm. It is under "Sonnar vs. Sonnars". search for "CZJ Sonnar MC 3.5/135mm" and you will see comparison shots. cooltouch narrowed down to six lens from the set and CZJ Sonnar MC 3.5/135mm is one of them. The resolution of CZJ on the right edge seems to suffer.

I believe that thread is referring to the Zeiss Contax 135mm f2.8 sonnar, which is also an excellent lens. It was interesting to read about all the old lenses and how they compared with each other.

Excellent review! I once owned one and love its color, bokeh and compactness. Then the aperture got stuck at wide opening and I sold it cheaply. There is an interesting review of 12 135mm lens including Zeiss Jena 135mm at http://forum.mflenses.com/twelve-2-8-135mm-lenses-compared-on-5dmkii-t39463.html

I used a K&F adaptor from amazon and it was 20 and pretty well made. It was for the M42 mount.

What a coincidence, I found a Carl Zeiss Jena (Biotar f2/58mm ) a few weeks ago attached to a Contax Zeiss camera for $15. I don't think its as sharp as your 135 at infinity but I think it may be the adapter I'm using. There is the slightest of gaps between the lens and the adapter. Its not as bad as the first adapter but the next step up is Novoflex which I'm not sure I want to spend that kind of money.

John

In order to test the sharpness at infinity, I used the NYC skyline. Below is the scene I shot at f8.

[url=https://flic.kr/p/AXT9Q5][img]https://farm1.staticflickr.com/689/22948517804_4381c01710_b.jpg[/img][/url]

I shot the scene in half stop increments from f3.5 to f8 moving from left to right in two rows. The f stops are f3.5, 4, 4.8, 5.6, 6.8, and 8. Below are the 100% crops in the center. If you can spot the difference stopping down, you are better than me.

[url=https://flic.kr/p/B2pprG][img]https://farm6.staticflickr.com/5815/22988369814_cebc4290bd_b.jpg[/img][/url]

Next is the lower right of the image. Here is does not clean up until f5.6.

[url=https://flic.kr/p/B2ppjs][img]https://farm6.staticflickr.com/5803/22988369394_73d1139855_b.jpg[/img][/url]

Top right

[url=https://flic.kr/p/B2vaua][img]https://farm1.staticflickr.com/693/22989493533_9d890cd5c4_b.jpg[/img][/url]

Top Left

[url=https://flic.kr/p/B2poLy][img]https://farm6.staticflickr.com/5764/22988367544_8e684f5a6c_b.jpg[/img][/url]

Mid upper right

[url=https://flic.kr/p/BWBi5d][img]https://farm1.staticflickr.com/614/23590464016_e1859a4d75_b.jpg[/img][/url]

Mid lower right

[url=https://flic.kr/p/Bqpfpk][img]https://farm6.staticflickr.com/5830/23248618809_77a9941ede_b.jpg[/img][/url]

The sharpness of this lens pretty good over the frame from about f5.6 onwards with maybe a small increase at f8.

For me, the carl zeiss jena represents an excellent compromise between size, color, contrast, bokeh, and cost. It weighs only 450 grams and comes with a built in hood. Its filter size means it integrates with my sony kit pretty easily. It is not sharp over the entire frame at f3.5 but by f5.6 it is pretty sharp all over. I definitely recommend this lens if you are looking for something small and light for your camera system that won't break the bank. You can find versions of this lens for under $100. I paid 130 for mine, but that was because it was in excellent shape and had the most modern coating on the lens. If buying make sure to get the multicoated version. Let me know if you have any questions.