CZJ 5cm 1,5 vs. CZJ 5cm 2,0

[raid]

I started out falling in love with a CZJ 50mm 2.0 lens that I got in LTM. Then, I read online that the CZJ 50mm 1.5 is one of the few lenses where a 1.5 is actually sharper than the 2.0 counterpart. I got curious, and Brian provided me with a 50mm 1.5 LTM. It is a wonderful lens, but I still like to see a clear-cut side by side report with images that show the 1.5 lens to be superior to the 2.0 lens at apertures 2.0 and smaller.

The J-3 copied the 1.5 CZJ and the J-8 copied the 2.0 CZJ. Both are great lenses. How is the 1.5 lens "better" other than having a larger max aperture? Is it resolution, contrast, bokeh, built, ... etc. ?



Who can add some information on this topic? I bet that Brain has tested both lenses.

 

[Sonnar Brian]

Must admit, I have not done a comparison on the same roll of film. I have two 5cm F2 Sonnars set in LTM mounts. I would state they are closer in performance to the Nikkor 5cm F2.

And- The 5cm F1.5 does seem to be sharper and higher contrast wide-open than does the uncoated 5cm F2. One reason, the glass on the F1.5 lens has fared better with age. It must not be as soft as the glass used in the F2 Sonnar and F2 Summar. Those optics seem to take a beating, lost of surface damage. I've worked on around 20 5cm F1.5 Sonnars, and most really survived the decades intact.

 

[raid]

Brian,

Your suspicion may explain why a 1.5 lens appears to be overall a better performer than a 2.0 lens by CZJ. A clean 2.0 lens is needed to test this myth.

 

[batterytypehah!]

I have a copy of the collapsible 5cm/2 with a serial number that, I think, makes it early wartime (23981xx). It came to me with a little bit of chrome lost off the aperture scale, a shiny layer of oil on the blades and faint haze on the inside of the front element -- but not a mark on the glass. Not bad for $50 shipped from the U.K.

It won't do for a lens test until I get around to cleaning it. Which I'm reluctant to do. It does seem more prone to flare than it ought to be, but I need some more practice before I dare take this one apart.

 

[Sonnar Brian]

That's a good price. The rear module is not too hard to get out. I need to post a thread on taking one apart. I have a practice one. One set screw holds the optics module in the mount, and then the rear module unscrews, usually with a rubber mat like a mouse pad.

239xxx puts it 1938"ish" or so.

 

[raid]

Shipping from Europe often is $20, so the lens cost $30! This is a very low price.

 

[raid]

This thread really died. What a bummer!

 

[furcafe]

I don't see why it would be unusual for a f/1.5 (or f/1.4) lens to be sharper @ f/2 than a f/2 lens, based on the general rule (perhaps no longer valid now w/aspherical designs & floating elements) that lenses don't perform their best @ their largest aperture. You simply have other drawbacks w/the faster lens, e.g., greater size & mass, possibly less flare resistance, etc.

I started out falling in love with a CZJ 50mm 2.0 lens that I got in LTM. Then, I read online that the CZJ 50mm 1.5 is one of the few lenses where a 1.5 is actually sharper than the 2.0 counterpart. I got curious, and Brian provided me with a 50mm 1.5 LTM.

 

[outfitter]

Must admit, I have not done a comparison on the same roll of film. I have two 5cm F2 Sonnars set in LTM mounts. I would state they are closer in performance to the Nikkor 5cm F2.

And- The 5cm F1.5 does seem to be sharper and higher contrast wide-open than does the uncoated 5cm F2. One reason, the glass on the F1.5 lens has fared better with age. It must not be as soft as the glass used in the F2 Sonnar and F2 Summar. Those optics seem to take a beating, lost of surface damage. I've worked on around 20 5cm F1.5 Sonnars, and most really survived the decades intact.

Scratches on lenses of that era were frequently cause by the common practice of wiping a dirty lens with the photographer's silk tie (yes men usually wore ties when in public)! As there were far more of the less expensive 5cm/f2 lenses and the very expensive 5cm/f1.5 was probably used less and cared for better, stands to reason more badly cleaned f2 examples floating around. I suspect the advent of coated lenses caused people to notice sooner the folly of the old wipe on tie trick.

 

[Sonnar Brian]

I've worked on a large enough sample of the uncoated lenses, I believe there was a difference in the glass. I'm not going to have it tested, though. I've worked on at least ten CZJ 5cm F2's and fifteen 5cm F1.5's. None of the F1.5's were badly scratched, all but three were mint glass without cleaning marks. Most of the F2 lenses did not hold up nearly as well, some were damaged to the point they were unusable. Almost all of them had haze on the surfaces on each side of the aperture, which cleaned off easily without etching the surface.

When buying a lens off of Ebay, all I am suggesting is that the F1.5 lens is the better choice as the glass is "probably" in better condition..

 

[Sonnar Brian]

Here is a shot with the Wartime 5cm F2 Sonnar "T" converted to LTM using a J-8 mount. This one is coated, and in quite good condition. It was listed as having cleaning marks on Ebay, and I got it for the minimum bid of $25.

My Nephew. Maybe F2.8? I stopped it down a little.

and his Daughter. Breakfast time, morning light behind her. Good flare test.

wide-open at F2.

The post-war CZJ 5cm F2 is a new design, the optics are bigger in diameter than the pre-war and wartime lenses.

I love the color-rendition of this lens.

The Nikkor-S 5cm F2 LTM and S-Mount lens are VERY close to it. But those cost more than $25!

 

[ZeissFan]

That's been my experience buying Contax cameras. Most of the collapsible f/2.0 Sonnars have cleaning marks. Most of the f/1.5 Sonnars don't. That's for the prewar lenses.

The post-war lenses are a bit different, and the final Carl Zeiss branded lenses seem to suffer element separation with greater frequency than the Zeiss-Opton branded versions. It's uncommon to find a postwar Sonnar (f/1.5 or f/2.0) with cleaning marks. Not impossible, but uncommon. And the coating generally has survived better than Leica lenses from the same era.

I've always been very pleased with photos from the postwar f/1.5 Sonnar. Not always as happy with the photographer.

I had a LTM Sonnar, but it was so poorly made and in such poor condition that I got rid of it. Piece of junk.

 

[Sonnar Brian]

Uncoated CZJ 5cm F2 converted to LTM.
Wide-Open

F4

Wide-Open

At F4

The colors are muted, and not quite as sharp. But a great lens for the right setting.

 

[Sonnar Brian]

> I had a LTM Sonnar, but it was so poorly made and in such poor condition that I got rid of it. Piece of junk.

I undeerstand about that! I spent several days rebuilding one, and ended up making a liner to guide the optics module as you focused. It was loose to the point that the RF cam would "wobble" and throw the RF of the camera off by 1m at 5m.

It is feeling much better now!
Wide-Open at F1.5.

http://ziforums.com/showthread.php?t=143

 

[raid]

The optics are worth in gold. Work around the mechanical problems if encountered.

Brian: I like the last image a lot.