[GibbyTheMole]

I've noticed that there are a couple of UV filters I have that periodically develop a hazy coating on them that needs to periodically be cleaned off, but it still leaves a very slight trace. They're in a dust-free environment with the cap always on... What's odd is that other filters on lenses in the same bag don't develop the haze.

I've also noticed the brand of filter doesn't seem to matter. I've also bought a couple of new ones that were hazy right out of the box.

Wonder what causes this kind of thing... Chemical reaction with plastic used in the lens? Gas generated from the synthetic innards of the camera bag?

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Last edited by GibbyTheMole; 06-03-2013 at 06:30 AM.

[Docrwm]

Does the haze disappear when they are left in direct sunlight?

[GibbyTheMole]

Does the haze disappear when they are left in direct sunlight?

Dunno... Haven't tried that. I wouldn't think it would be fungus, though. None of my lenses have even a trace of it. I might give it a go, though. How long do they have to be left in sunlight?

[altopiet]

develop a hazy coating on them that needs to periodically be cleaned off

Bob, I'm thinking about something else. I live in a hot part of my country, and regularly find this kind of thing on the inside of my car windshield, especially when it stood in the sun doors locked, and windows closed. Why does inside car windshield become greasy (oily) after sitting in the sun? Why doesn't Windex remove it? - Yahoo! Answers. Is it possible that the heat and other factors they mention in the link might be a factor? Then again, why only certain filters and not all of them?

[GibbyTheMole]

Bob, I'm thinking about something else. I live in a hot part of my country, and regularly find this kind of thing on the inside of my car windshield, especially when it stood in the sun doors locked, and windows closed.

I usually keep my camera gear out of super-hot & humid conditions as much as possible. Of course, that doesn't mean it's not the same thing causing it...