Need advice on a damaged DSLR I purchased

bromodomain · Post by **bromodomain** » Fri Apr 12, 2019 11:47 pm

Hello,

I purchased a used Canon 50D on ebay with the hope of connecting it to a Zeiss Phomi III. When the camera arrived I inspected the reflex mirror and noticed a large patch on it, seems like rubbing marks but I could be wrong.

I know that you should never attempt to make any sort of contact with the mirror as the top silver layer is extremely sensitive and damage to it can affect autofocus and metering due to altered light transmission. As my original intention was to use remote live view shooting its not a complete deal breaker but I am also interested in exploring photography in general (no experience whatsoever).

What would be your advise, should I request a (partial) refund?

Thanks
BD

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rolsen · Post by **rolsen** » Sat Apr 13, 2019 12:04 am

Back in film days I used an air blower can and didn't know (read the manual id est) that it should not be turned upside down. Well, I turned and then it spit cold liquid into poor Canon's mirror. I called to the service and first listened a tight sermon for many minutes and then was told to get medical gasoline from pharmacy store where it was sold (in our language it is "purified gasoline" and it is used for cleaning purposes), not sure about its name in your area. But, that did the trick, I got my mirror clean again.

bromodomain · Post by **bromodomain** » Sat Apr 13, 2019 12:16 am

Rolsen, thank you for you reply.

I regularly use petroleum ether (also labeled as high purity benzin which is German for gasoline I think) for cleaning the front lens of oil immersion objectives (evaporates instantly).

I actually thought about doing exactly that but I didn't want to ruin the mirror by stripping the top silver layer so decided to ask the experts on here

BD

rolsen · Post by **rolsen** » Sat Apr 13, 2019 12:30 am

I have to say that camera manufacturers are very strickt about handling the mirror, don't touch, don't clean, no liquids, no fingers, no anything. But in that condition that mirror is pretty bad already. I do use isoprophyle alcohol for some cleaning if needed and it should be a bit friendlier than gasoline, but it does not do very well with grease or oily residues and dirt.

lothman · Post by **lothman** » Sat Apr 13, 2019 4:09 am

bromodomain wrote:I regularly use petroleum ether (also labeled as high purity benzin which is German for gasoline I think) for cleaning the front lens of oil immersion objectives (evaporates instantly).

Zeiss sold a lens cleaning fluid with was from 85% Benzin (pure perol ether) and 15% Isopropanol. I also used that for cleaning mirrors. I think damaging the coating of the mirror is not done by solvent but by mechanical abrasion. So film cleaning might be the best.
I would try Benzin on a Cotton swab and see wether this dull area wipes off. If not I would try to get refund.

ray_parkhurst · Post by **ray_parkhurst** » Sat Apr 13, 2019 5:10 am

I'd just return it for refund and buy another.

bromodomain · Post by **bromodomain** » Sat Apr 13, 2019 5:31 am

lothman I have used that formula in the past (specifically for microscopy) but used n-hexane in place of benzin, worked nicely.

ray_parkhurst I returned the camera for a full refund and purchased another one of the same model with a shutter count of 2000 (the one in the OP was 13K) for only a 30 euro difference. The seller seemed to have a very decent reputation for seling mint condition photography equipment so we shall see.