CZJ 5cm 2.0 (1938) collapsible, in Contax mount

[former member]

Do you feel the ƒ/1.5 to be superior to the ƒ/2 versions? Sounds like TenEleven hasn't any good things to say about the Contax Sonnar altogether.

I think he is commenting on coated Sonnars being much less rare than most people believe. On my own copy: I was told that there is one 5cm F1.5 Sonnar lens with a lower serial number that is also coated. Some people stated that my lens must have been coated after manufacture. I believe it is original, and TenEleven's statements reaffirm that belief.

The 5cm F2 Sonnar is as good as the 5cm F1.5 IF you can find one with clean glass. I see at least 10 F1.5 Sonnars with clean glass for every F2 lens. The front glass is that soft. It is like trying to find a perfect glass Summar. I have Five pre-war F2 Sonnars now, cherry picked- all usable. The 1934 is as close to perfect as I've seen.

 

[raid]

The CZJ 5cm lenses can result in beautiful images, both in color and in B&W. I have used many lenses over the years, and I love the two Sonnar CZJ lenses.

 

[raid]

Do you feel the ƒ/1.5 to be superior to the ƒ/2 versions? Sounds like TenEleven hasn't any good things to say about the Contax Sonnar altogether.

Both lenses can be excellent if found with clean glass. I like using both.

 

[former member]

1934 5cm F1.5 Sonnar, wide-open. Not coated, but a beautiful bloom on this lens.

Imagine the impact this lens made in the Mid 1930s.

sonnar_1607_3 by fiftyonepointsix, on Flickr

Converted to Leica Mount.

Manassas Christmastime by fiftyonepointsix, on Flickr

With a Bloom like this, who needs a lens coating.

 

[james.liam]

Both lenses can be excellent if found with clean glass. I like using both.

What do you see as the difference between them?

 

[TenEleven]

Thank you Brian, yes that's what I meant. Also centrally well-resolving Sonnars are not that rare either, if as Brian said the glass is in good condition.

Regarding the coatings let me quickly ramble through my thoughts and reasoning for that, then you can make up your own mind.

• As stated I have had about ten coated Contax mount lenses from 1936 onwards plus one coated Super Zeiss Ikonta from 1937, all had the same blue-ish color to it. I have also seen it in several dozens more Zeiss lenses in various mounts. Yet, I never see this particular coating in other brand lenses (Leitz coatings look different)
• I have however seen one post-coated 5cm f2 Sonnar from 1937, however the coatings were more purple-ish and extremely soft to the point where I could not clean the lens and had to leave it hazy - this is very different from the coatings that Zeiss used which are harder because I assume they had been baked into the glass. Which takes me to my next point
• The CZJ Sonnar 5cm f2 has brass mounted glass. Save the rear fixture, from which the glass can be extracted the lenses are to my knowledge permanently glued or stamped in. One could perhaps remove them, but that would risk breaking the bond of the Canadian balsam or other worse disasters. One could do a vacuum deposit coating I guess, without baking the lenses or glass which would result in the ultra-soft coating described above - because it would literally just be a fine film covering the glass (and brass which will be wiped off).
• Then, I question the economic viability of some camera shop offering to coat lenses to customers at a cost they would find reasonable during the relevant period that the Contax I and II saw use. First is the equipment and installation cost to the shop, then you need trained staff. All this in a time period of let's say between 1940 and 1955 when that service could be relevant to a Contax II user. And lastly you would need to have to have a photographer with deep-enough pockets who loved the Contax II and lenses so much that he would be willing to pay to have his lenses Coated all the while coated lenses and new camera systems were being rolled out quickly. Yet our imaginary photographer doesn't buy one of these new cameras.

 

[raid]

What do you see as the difference between them?

The main difference is the OOF at 1.5 is slightly different from wide open at 2. Not much of a real difference really.

 

[jc031699]

My 1934 5cm F1.5 and 1936 5cm F1.5 both have a beautiful bloom on them. You must be very careful when cleaning these lenses to leave it intact. My 1934 Sonnar had never been cleaned and when I got it. My 1936 5cm F1.5- very close to my fully coated 1936 5cm F1.5, made in the same batch.

Curious how one distinguishes bloom from haze due to lubricant vapors etc? I worry that I will clean my lens elements in error.

I have an uncoated CZJ 50/1.5 on the way…

 

[former member]

@jc031699

Bloom tends to be mostly on outer surfaces, as it is a reaction with air.
Haze- usually internal, and on each side of the aperture blades.
Bloom is an effect in the glass, haze is deposits on top of the glass. The latter- usually cleans off with lens cleaning fluid and lens cleaning paper. SO- just wipe gently!

 

[TenEleven]

What do you see as the difference between them?

I do have good things to say about these lenses in fact I have at least 20 of these altogether.
That would be a rather strange thing to do with a type of lens I dislike, wouldn't it?

I very much like them, but they do have limitations, I will not go into great lengths here as I have covered this elsewhere and I do not want to derail this thread. In short:

• The f2 Sonnars in general have less-to-no distortion in comparison to the f1.5 lenses. However, even the "worst" f1.5 I have do not have an objectionable amount, for my tastes. Distortion varies a bit sample by sample. For the post war lenses Zeiss managed to close the gap and post-war 1.5 lenses have less pincushion distortion overall.
• The f2 Sonnar appears to be a bit worse (less contrast, more spherical aberrations, field curvature) in the center than the f1.5 Sonnar stopped down to f2.
• However, the f2 Sonnars' corners improve at a faster rate than the f1.5 Sonnar. Again, Zeiss closed the gap here with the post-war lenses, the trade off is worse wide-open performance on the post-war lenses.
• Lastly, the f1.5 lenses, by virtue of having more strongly curved lens elements suffers slightly more from focus shift. Something Zeiss slightly improved with new aperture blades in the post-war version at the expense of nicer bokeh. However, even with the pre-war f1.5 lenses, I do not find this to be an issue in practical shooting on film.

In a nutshell if you like the Sonnar look, shoot film and want an all-round lens the f1.5 is a great choice. If you see yourself shootling a lot of far-away landscapes or subjects where distortion is absolutely critical maybe add that f2 to your bag as well.