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#1 Steven Budden

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Posted 18 May 2005 - 08:32 PM

Anyone have a safe way of cleaning the lens element on a switar 10mm preset? I'm not sure what kind of coating is on there... I know they've evolved over the years. An old time camera buff used to tell us to put some powdered charcoal on the lens and gently dust it off with a q tip, as a way to avoid harsh liquid cleansers. Is the outer glass pretty fragile on these things? No scratches or cleaning marks... I guess it was just stored without the lens cap for a while, in the case but still... little specs of whatever.

Any help appreciated.

Thanks!

Steven
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#2 Steven Budden

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Posted 19 May 2005 - 11:29 AM

Also, it looks like there might be one spec of fungus off to the edge, outside of the image area. Is there a way to keep it from spreading or should I send the lens back? One tiny speck. I'm taking the lens to have it checked out today but I was hoping to get another professional opinion.

Thanks!

Steven
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#3 Ian Marks

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Posted 19 May 2005 - 02:56 PM

Steven, whoever told you to put powdered charcoal on your lens must have been pulling your leg. Wiping your lens with that would only etch the glass! The best advice I've ever read about cleaning lenses is to do it as little as possible. A speck of dust on your front element isn't going to have much effect on your image, but grinding that same piece of dust into your coating might. I always start by blowing off the lens with compressed air - if you use the canned stuff do NOT tilt the can, as liquid propellent can be discharged and ruin your lens - and only then do I attempt to wipe the element. I use lens cleaning paper with a tiny bit of lens cleaning fluid or a micro-fiber cloth made specifically for the purpose. Once a lens has been cleaned to my satisfaction, I like to keep a filter on it, usually a UV or an 85, at all times. I would rather have to clean my $10 filter than my much more expensive lens.
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#4 Steven Budden

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Posted 20 May 2005 - 11:23 AM

Steven, whoever told you to put powdered charcoal on your lens must have been pulling your leg. Wiping your lens with that would only etch the glass! The best advice I've ever read about cleaning lenses is to do it as little as possible. A speck of dust on your front element isn't going to have much effect on your image, but grinding that same piece of dust into your coating might. I always start by blowing off the lens with compressed air - if you use the canned stuff do NOT tilt the can, as liquid propellent can be discharged and ruin your lens - and only then do I attempt to wipe the element. I use lens cleaning paper with a tiny bit of lens cleaning fluid or a micro-fiber cloth made specifically for the purpose. Once a lens has been cleaned to my satisfaction, I like to keep a filter on it, usually a UV or an 85, at all times. I would rather have to clean my $10 filter than my much more expensive lens.

<{POST_SNAPBACK}>



Ian,

The charcoal thing is mirculous for grease on the lens. I actually was borrowing my boss's camera for a weekend and I spilled something stubborn on it, so I needed a miracle, as it were, to avoid paying him retail for the thing. I brushed off larger particles with a sable artists brush. Then, activated charcoal from the health food store. Put a tiny bit on a q tip, shake off remaining, and very gently swab the lens in upward motions. Grease begins to vanish with no cleaning marks. I think this is no an unheard of practice for use on older still lenses where the coating is not as advanced. Newer lenses have coatings that can take the liquid cleaner.

Also, I read in a post or somewhere never to use compressed air, because it can blow particles so hard it embeds them in the coating, not to mention the potentially disastrous liquid spurting out, which could happen even if the can is not tilted. So far my filmmaking knowledge is mostly theoretical... ie, I'm trying to learn the easy way. That 10mm switar I just ended up sending back. I don't care how little fungus is in there, I want to start with something immaculate that will last and hold some value.

Steven
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#5 Steven Budden

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Posted 20 May 2005 - 11:26 AM

And I definitely agree that the best philosophy is to just keep your lens clean in the first place. I plan to do just that. Seriously though, try that charcoal thing on a throw away or a test piece sometime. It's interesting to say the least.

Steven
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