ILEX Acuton lenses

[Mark Volle]

I have a ILEX ACUTON 7 1/2" (190mm) f:4.8 lens in a Copal 1. It seems to have some deterioriation of the coatings on both surfaces nearest the shutter. On the rear element the deterioriatin seems to cover about 50% of the element but I am not sure which is good/bad part. I have gotten both clear and splotchy images from the lens depending on lighting.

Keep the shutter and toss the lens? Try to remove the rest of the coating on the really bad element?

I have 135mm and 210mm lenses I like so the 190 isn't critical but it is easy to focus at F4.8

[Conrad Hoffman]

If the coating is really really bad, it can be removed with the appropriate optical polishing compound, some water, and a cotton ball. This won't affect the glass, and the cosmetics will be greatly improved. As for how much the bad coating is affecting the image, it's hard to say. Sometimes coatings that look awful don't have nearly as much effect on the image. If you don't think the lens is worth keeping, you have nothing to lose by trying to clean it up, though it's a very tedious process.

[William Mortensen]

As the lens seems worthless to you now, I'd try a serious polishing of those inside elements using a strong solvent. It's odd that the inside elements are damaged, and I wonder if someone used the wrong lubricant on the shetter on a CLA, and the lubricant migrated to the inner lens surfaces and dried there.

[Mark Volle]

Thanks for the responses!

I do think that the lens was damaged by something used on the shutter. The outer surfaces of the lens are OK, only the inner faces are damaged.

I may try removing the coating. Was the lens decent before it was damaged? I can't find any information on the 190mm.

Thanks