Kiron 70-150 f/4 cloudiness. Separation?

wupdigoj · Joined: 18 Mar 2010 Posts: 85

Hello. My "new" kiron 70-150 has an inner element with something that looks a lot like condensation (and a lot of fungus in the frontal group, which cleaned nicely). The borders of the element are not affected, only the central part (about 2/3 of the diameter). The cloudiness is partly structured in rings. After accesing the element, it results that the hazy is inside the element, not over the outer surfaces. Is this separation?. I thought this problem could appear mainly in older lenses, glued with canadian balsam. Is it frequently found also in newer lenses? (first time I see it). I suppose it can not be repair Crying or Very sad

, but any suggestion would be welcome. Thanks

Javier

PD: I have just read the excellent article from John Goodman, and I think It answers my questions. I will try the lens just like it is now. If the results are not acceptable, perhaps I will try something else...

sadness · Joined: 16 Aug 2010 Posts: 49 Location: Constanta, Romania

Well, I can say that I accidentally unglued one doublet from a lens and after putting back the lenses without glueing them back, the loss in quality is not that significant, I didn't test it before but the quality is average like presented by other members of the forum.

If you are not satisfied with the quality without cleaning, you can try it.

Splitting can be done by holding the group under hot water for some time Wink

wupdigoj · Joined: 18 Mar 2010 Posts: 85

I have some results from this lens. It is sharp, but there is lots of flare. For B/W could be O.K but not for color negative, and althought not tried, even less for slide film. So... I will try to fix it. The doublet (I suppose it is a doublet) is mounted in a metal ring. I will try to extract the glass from the mount and unglue it.

Javier

wupdigoj · Joined: 18 Mar 2010 Posts: 85

Several days in acetone, several days in a strong paint solver, and noting at all. The doublet does not want to separate. I am not patient enough to wait for weeks, so I will mount it in the lens again and will try with B&W film.

Javier