Any hope for this terrible haze? Mamiya-Sekor 90mm f3.5

Summary: My lens has bad haze, I’ve tried a bunch of stuff. Is there anything I should try that I haven’t or should I live with the haze?

I bought this lens as a donor for another 90 that was working well. But now I’ve got myself a little project.

Among many other issues, it has some nasty haze on the rear element of the front cell.

Now, this is no ordinary haze! I have tried all the lens cleaning solutions I can think of. Leans cleaner, IPA, naphtha, acetone. The glass itself has an almost “matte” feeling to the touch.

My best bet is that whatever caused this haze has etched itself into the coating (or potentially the glass).

One the plus side, the haze is invisible to my eye dead on, and the lens captures sharp images (potentially with some loss of contrast but it’s hard to tell because the back I was testing it with had light leaks).

So here’s my question! Is there an approach to this haze that I haven’t tried but I should?

I'd try polishing it. Obviously that surface would not be coated any more and the curvature could be altered. However, contrast will be improved.

ic-racer said:

I'd try polishing it. Obviously that surface would not be coated any more and the curvature could be altered. However, contrast will be improved.

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Got a favorite polishing compound?

Cerium oxide - available from Amazon and various sites that sell DIY telescope supplies.

You will need to make a pitch lap.

Look at various telescope sites.

Some would pay money to have lens haze like that.
I take it the portrait was made with the lens. looking good, sort of old school.

Try to locate the haze with certitude first. It could be in the cemented rear group. In which case you have to separate the group, clean and re-cement. I've done it once and it's not easy.

BTW to make a pitch lap you can use pine rosin found at your natural/health type store.

Edit. Oops, I just read it's on the front group. Polishing with CeO2 should do it.

Steve@f8 said:

Some would pay money to have lens haze like that.
I take it the portrait was made with the lens. looking good, sort of old school.

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Yeah, the portrait was taken with this lens. I agree that it’s not terrible (and I was being careful not to catch a flare). I think the lens actually has quite a bit more contrast available to it, but the back is leaking like a sieve. Also the lens is back focusing so everything is a little soft.

Ha, it has a lot of work.