Pre-War CZJ 5cm F1.5 in LTM J-3 Mount, sample shots

[lens_hacker]

A follow-up to the thread on Summicrons vs Nikkors. Felt bad about getting off topic on the CZJ Sonnar.

I have several Nikkor 5cm f2's and 5cm F1.4's, in both S-Mount and LTM. (and seven 50mm Summicrons...none in S-Mount yet...) But there is something about the Zeiss lenses that is "just a bit different". I took some apart and learned that the pre-war and wartime 5cm f1.5 and 5cm f2 CZJ optics modules from Contax mount lenses could be mounted in LTM J-3 and J-8 mounts, respectively. Aperture rings, shims, and variable stand-off rings are compatible.

The CZJ Sonnar 5cm F1.5 in a J-3 mount:

Collimated for wide-open and close-up:

Wide-open at F1.5, on the Canon P:

Tight-Crop:

Another wide-open, a bit farther away:

Tight-crop:

Focus with this lens wide-open is good to 100ft or so, best to stop down a little for true infinity. The Contax focal length is slightly longer than what an LTM RF is calibrated for.

Compared with the Nikkor, the colors are a bit more muted and the contrast is lower. What you expect from uncoated optics, although this particular lens has a coated front element- aftermarket I'm sure.

 

[benjiboy]

I have this lens on the pre ww11 Contax that my dad got me started in photography with in 1954, I find the lack of contrast quite charming it produces a lovely retro feel to the images, however this is not to be confused with lack of definition in terms of l.p.m this is a very sharp optic, it's just that the greater contrast adds to the apparent sharpness, something that lens manufacturers realized later IMHO

 

[André E.C.]

First of all, congrats for the excellent work mounting Zeiss optics in Leica thread mounts, keep up the fantastic work!

Second, I was a tad responsible for the mess created on that other Leica thread, but, was it really that off-topic?

Weren't the Sonnar 50mm f/1.5 and the Nikkor 50mm f/1.4 direct competitors?

Both lenses don't share the same optical design?

Isn't it the performance of the optics similar in almost everything?


My example was more of an indirect/hiden hint, to go for the Nikkor optic. Maybe I need to hurt the feelings of the Leitz guys and put it straight on the table, Go Zeiss always, LOL.



Cheers



André

 

[lens_hacker]

> Both lenses don't share the same optical design?

They are the same block diagram, but a different "prescription". The glass and curvatures of the elements are different. The Nikkor has more harsh Bokeh, higher contrast, and I believe less field curvature.

The Nikkor 5cm F1.4 changed it's "prescription" after the first couple of batches. The diameter of the elements was increased. i learned this by taking a couple of them apart to repair a badly dented front ring. The glass of the 1950 Nikkor passed through the front mount of a 34x mount. The entire mount and all of the optics were about 1mm less in diameter. The change-over occurred somewhere in the early "made in Japan" lenses. I suspect it is when the S2 was in development, and the 24x36 format was scheduled to replace the 24x34 format of the Nikon M and Nikon S.

The post-war Sonnars also changed the formula, used newer glass. The Zeiss-Opton optics will not fit into a J-3 mount, the design of the mount changed dramatically. The post-war CZJ 5cm f2 optics module did not fit into a J-8 mount. Successes so far are with collapsible 5cm f2 optics modules in J-8 mounts, and pre-war CZJ 5cm F1.5 in J-3 mount.

 

[df cardwell]

The Zeiss Jena lens design had not evolved beyond the 1937-38 era,
and in the years Zeiss was struggling to re-establish itself in Germany,
the MacArthur Vice-Regency of Japan helped clear the way for Nikon. Nikon seemed to overlap
the Zeiss versions (take a peak here: http://imaging.nikon.com/products/imaging/technology/nikkor/n34_e.htm)

So BOTH the Opton and 1.4 Nikkors were well evolved designs by the mid '50s.
Although they both derived from the mid '30s Bertele design,
they both were well beyond it. And for both, time was running out on the Sonnar-as-normal-lens,
for it was a very difficult lens to manufacture,
and the Double Gauss / Planar / Xenotar offered both design and manufacturing advantages.

 

[André E.C.]

Found this excellent article by Robert J. Rotoloni, about one of the biggest ripp-offs of the history of optics design, the Nikkor 50mm f/1.5.


http://www.pacificrimcamera.com/nhs/50f15/50f15.htm


Post-war Zeiss (1950) claimed that product was a direct and shameful copy of their Sonnar, a few months later of production, Nikon "re-designed" the optic and the 1.4 was born, with alot of trades in out of focus areas for sharpness. Later in the sixties, I've been told, they re-designed the optic once again, adopting at the time, a planar design.


Zeiss Sonnar 50mm f/1.5

Nikkor 50mm f/1.5

Nikkor 50mm f/1.4

Cheers



André

 

[df cardwell]

about one of the biggest ripp-offs of the history of optics design, the Nikkor 50mm f/1.5.

Andre, take a look at the Nikon article. It deals with primary sources,
and should hold more importance than Rotoloni's.
It's possible you've over simplified what really happened;
there is a bit more to the process than a block diagram.

To be sure, the Zeiss patents may have prevented the Nikkor design from reaching a common marketplace,
but the German patents were suspended. Nikon built their lenses, and the rest is history.

I've always favored Sonnars, and have owned way too many of them. I'm glad Nikon got into the game,
as well as Asahi and Konica, for the various flavors their designs provided.

Murakami obviously used Bertele's Ernostar-Sonnar line as a starting point,
and succeeding Nikon designers carried it on. But to accuse Murakami of "shamelessly copying" Bertele
is like accusing Bertele of 'ripping off' the Cooke triplet, FROM WHICH THE SONNAR EVOLVED.

 

[lens_hacker]

The Nikkor 5cm F1.5 and Canon 50mm F1.5 are based on the Sonnar, but are not "exact" copies. They use different glass and are 51.6mm focal length for the Leica standard. I have two early Nikkor 5cm F1.4, but not an F1.5. The early F1.4 lenses look a little closer to the Sonnar than the later ones.

 

[lens_hacker]

An old thread, but worth a follow-up.

I've converted a 1939 Carl Zeiss Jena 5cm F1.5 "T" Contax mount lens to LTM using a J-3 mount. This is one of the first coated lenses. Construction is a bit different from the earlier uncoated lenses. The Optical Fixture is made from a lighter allow than the 1938 lens that I've converted. The aperture stops down to F22 instead of F11.

VERY IMPORTANT: there is a set screw that holds the rear module in place, and another set screw that holds the front ring in place. The older lenses do not have these hidden set screws. You have to take the optics module out of the mount to see the rear set screw. Undo it to get the rear block out. You have to take off the aperture plate to get to the front ring set screw. Do not try to remove the rear block or front ring without checking for these screws. Someone tried to force the issue on the lens that I received. Some plier marks, not too bad. Beautiful Optic.