Topic: element separation

[MrclSchprs]

Hello,

I'm on the look out for a new portrait lens. A Pentax-M 100mm F/4. You'll see them quite often on various auction sites. With the risk of exaggarating, I think that half of them suffer from element separation with a little haze that goes along with it. A rough estimate based on what the seller is willing to tell. Seems to be an issue with this lens. Now I am wondering is element separation and haze removal something that is covered by a CLA? Looking forward to your thoughts and experiences on this. Have a nice day!

[02Pilot]

No, it is not covered by a CLA. Balsam separation requires separation and recementing of the lens elements. It's a tedious process, even if one uses the more modern UV-curing cement rather than traditional balsam. However, the good news is that the effect of minor separation on images is likely to me negligible in most conditions. I have a lens with a big ugly section of complete separation - it looks like there's a jellyfish suspended in the glass - that is completely invisible in photos, even straight into the sun. Use a lens hood and chances are you'll never notice it's there.

[Francois]

And if you want a diy solution to a proper fix, check the Edmund science optics website. They carry uv curing cement.

[02Pilot]

Personally, if I was going to try to DIY (which I may well at some point), I'd go for traditional balsam. It's more forgiving, and if I screw up I know I can separate it and try again. With the UV cure stuff, one chance is all you get.

[Francois]

Well, there are advantages to the UV stuff too. One of them is that it stays liquid forever until you give it a shot of UV light. This means you can take your time to align it and once it's ok on the workbench, you then move the UV light over it to make it cure. In the instructions, it says it takes 1 minute to cure.
https://www.edmundoptics.com/lab-production/adhesives/norland-optical-adhesives/1597/

[Late Developer]

I had a bit of balsam separation in an old pair of lenses I used with my Mamiya C330.  I was quite alarmed when I found it but when I looked back at the photos I'd taken using those lenses, I was surprised not to see any evidence of it degrading the images.  Once I'd had it confirmed that the lenses didn't have fungus (that was what I'd originally thought the slight "blooming" I could see was) I kept and used those lenses for some years.

The only "real" downside was the fact that it made selling / trading a bit difficult as any new owner / user would probably be a bit circumspect about buying lenses with visible flaws.