How to remove front element CZJ 85/2

dexdog

dexdog

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I have a 1937 vintage CZJ 85/2 Sonnar with a large ring of haze on the interior of the front lens element. Ordinarily I would unscrew the name ring, pop out the element and clean it. My problem is there are no spanner slots on the name ring, the lens element is convex, and I cannot get a rubber stopper in to try to unwind either of the threaded bits. Any ideas? I have taken a dozen images with the Sony and the ring does not appear to have a noticable effect on pics. Lastly, other than the ring of haze the glass is flawless. Yeah, it flares quite a bit when put into that situtation, but similar to the other uncoated CZJ 85/2 that I have.

 
I've done this- I remember the front section will unscrew from before the aperture, then middle group comes out from the rear, held with a retaining ring- exposing the back of the front element.
 
Thanks, Brian! I will give it a try tomorrow, if I feel brave enough. I notice that there is a tiny grub screw on the milled ring in front of aperture ring; I assume the screw needs to be removed.
 
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OK, got the front of the lens unscrewed, it was in there really tight. It looks to me like the chunky brass fixture holding the middle lens group in place screws into the fixture holding the front lens element, do not see any retaining clips.


I tried to unscrew the two pieces, could not move them, decided against trying to persuade it using lighter fluid and a pair of band clamps. I put the lens back together figuring that while the ring of haze detracts from the appearance, the lens works well and takes good pics. Ya know, I am getting pretty good at seeing the divots for seating the grub screws through the 1mm tapped holes. Of course, the 20x magnifiers help :)
 
If you use lighter fluid- the Black Paint that prevents reflections will likely come off.

I've also learned to leave 95% solutions in place, rather than destroying an 80 year old lens trying for that last 5%.
 
Sun is just starting to starting to shine into my office window. First pic is the "ring of haze" uncoated 85/2 Sonnar from 1937 wide open focused on the dried flower heads about 7 meters. Second is my Zeiss-Opton coated 85/2 Sonnar wide open same distance. The later coated lens is obviously better, but the difference is not huge, mostly one of improved constrast as one would expect with a fully coated lens

 
I looked at the fitment between the fixture holding the middle lens group and the fixture holding the front lens element. I recall that when Henry Scherer overhauled my 1935 vintage black and nickel 85/2 Sonnar in 2005 he sent me a note saying that he could only take the lens apart to a certain point to clean because several of the lens groups were press-fit into place, and could not be removed for this reason. The lens in this post is an early chrome lens, and very similar to black and nickel design. I looked very closely at the joint between the front fixture and middle fixture with a 20x lens, and could not see any threads, makes me wonder if this lens is press-fit. Speculation on my part, of course.
 
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More lens tests between haze ring 1937 85/2 and Zeiss-Opton 85/2. Wide open at f2
Zeiss-Opton 85/2 wide open at 6 meters

Haze ring 85/2 wide open at 6 meters
 
Extreme flare test. Sun is about 15 degrees right and 30 degrees vertical as judged by my Suunto clinometer. Of course, I would not usually take a picture at these extreme conditions, but lens testing and potential sensor frying is entertaining. Flare is better controlled with coated lens, not too surprising.
Haze ring 85/2 wide open

Zeiss-Opton 85/2 wide open
 
I am really surprised that as awful as the ring of haze on the 1937 lens looks, it does not have a dramatic impact on the images. I suspect the haze ring would show more effects if I stopped the lens down to f8 or greater. Rest assured that I will spare RFF that experience.
 
a couple of pics taken under ideal conditions (indirect light no shadows) with haze ring 85/2 and Zeiss-Opton 85/2.
Haze ring 85/2 wide open

Zeiss-Opton 85/2 wide open. I could really only tell these two apart because a bee landed on the hibiscus when I was swapping lenses.



A crop of a bee butt of the above photo with Zeiss-Opton lens
 
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dexdog said:
a couple of pics taken under ideal conditions (indirect light no shadows) with haze ring 85/2 and Zeiss-Opton 85/2.
Haze ring 85/2 wide open

Zeiss-Opton 85/2 wide open. I could really only tell these two apart because a bee landed on the hibiscus when I was swapping lenses.

A crop of a bee butt of the above photo with Zeiss-Opton lens
Click to expand...
I think in the last post you attached the Pre-War Sonnar photo (without the bee) twice. The bee is only visible on the crop, not on the actual image. I can't make out any differences in the two photos.
 
dexdog said:
Sun is just starting to starting to shine into my office window. First pic is the "ring of haze" uncoated 85/2 Sonnar from 1937 wide open focused on the dried flower heads about 7 meters. Second is my Zeiss-Opton coated 85/2 Sonnar wide open same distance. The later coated lens is obviously better, but the difference is not huge, mostly one of improved constrast as one would expect with a fully coated lens

Click to expand...
I notice the smoother background Bokeh of the pre-war 6 element Sonnar. The 7 element Option is a little more busy. But the contrast and clarity of the Opton is very nice in this photo. Interesting comparison.
 
lukx said:
I think in the last post you attached the Pre-War Sonnar photo (without the bee) twice. The bee is only visible on the crop, not on the actual image. I can't make out any differences in the two photos.
Click to expand...
thanks, I will check. Smugmug does not retain original file names.
 
Lukx, you are correct, I posted wrong photo for the Zeiss-Opton lens. I fixed post #12 to include the one with the bee's ass. Correct photo with visible bee butt is attached again in this post. The lenses are so close in performance under ideal conditons that it is hard to distinguish between the two.
 
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Hello
My chrome Sonnar is earlier but looks the same, it is the serrated ring that holds the front lens, so I had to fit a rubber stopper to the job.
 

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JakobN, thanks for the tip. I ground down the rubber washer as shown in your post, and was able to get the serrated ring off. Ring of haze cleaned off easily, now all I have to do is put the thing back together! I was able to screw the serrated ring in using the modified washer, went back together much easier than removing it. Difficult and a pain the butt, cannot argue with results!
 
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