Advice needed on lens element separation

[Noll]

I've gotten myself into a fine mess. In the process of "repairing" the shutter on my Zeiss Ikonta 523/16 folder (f3.5 Opton Tessar), I bent the tube enclosing middle 2 lens elements by using a pliers 🙂bang: ) padded with a rubber-band to get it un-stuck. Upon reassembly, I find out the front lens element won't screw on or focus properly due to the bent tube

Frustrated and determined to fix it, I bought a parts camera that cost more than the original, unscrewed the front and found element separation surrounding the perimeter of the center group. There's about 1-2 mm separation around the edge where it looks pretty ugly, the other 98% of the lens is fine.

Now, I realize that the separation as-is will have virtually zero effect on my images. My question lies in how much worse it's liable to get, especially if I subject it to warm-cold temp changes (nothing too sudden) in winter? Is fungus likely to follow? Might I might be better off to just return the parts camera and take a chance on another one? Thanks for reading and thanks for any advice!

 

[Steve M.]

You're right in thinking that sudden temp changes could make things worse sooner than later. Doubtful that fungus will follow, but no one knows if the lens will go another 2 days, years, or decades as it is. I had a similar issue w/ my Tessar and ended up sending it off to Focal Point here in the US. It was not cheap to fix, as John explained that the Zeiss Tessars were pretty difficult to open, clean, re-cement and put back together. It ran me over $250 plus shipping. Took stellar photos afterwards, but of course I took a bath when it was later sold.

 

[Noll]

Thanks for laying out the repair option, Steve, unfortunately I don't think I can justify that kind of expense. Like you said, it's a wonderful lens, but the camera itself isn't all that valuable.

After some reading on www.zeisscamera.com, I learned that pre 1960, zeiss used some kind of balsam resin to bond the lens elements together. Since this is a ~1958 camera, it likely uses this resin. Some folks have apparently had success heating up the lens to about 150 degrees F, which softens the resin and can allow the elements to re-bond. Seems extreme, but maybe someone here has tried it?

 

[nhfoley]

I stumbled across these posts while searching for a solution to element separation inside my own lens - a Canon LTM 35mm f2. The inner rear doublet had wrinkled, web-like separation covering most of the element.

I couldn't find any solid evidence that Canon lenses from this era indeed used Canada Balsam (online sources say vaguely that it "began getting phased out after WWII"), and not a synthetic glue... but I decided to try to re-melt it regardless.

Putting the element in the oven directly seemed dangerous though, as 1) the metal housing of the doublet was proving difficult to remove and I was worried about mismatched thermal expansion, 2) I'm not confident my gas oven has controlled, even heating. Instead, what I did was double-boil the element - putting it in a zip-lock bag and dangling it by hand in a pot of boiling water.

After 2 or 3 minutes, I took the group out and let it cool slowly. When it was room temp, I took it out of the bag, and was very excited to see that the elements had completely re-glued and were now flawlessly clear.

Hopefully this helps some people.

 

[rjbuzzclick]

Here's a DIY article by Jon Goodman on re-cementing lens elements:

http://www.fotomozaic.ro/artikel.php?s=1&categ=21&idstory=412