How to clean dust in the focusing screen?

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I bought brand new Canon EOS 300 and 28-105 USM lens last month. But recently I found that dust invading my focusing screen, I tried to clean the mirror but the dust still there. My friend said maybe the dust was in the top of the pentaprism. I just can't belive this, I just use this body for about 3 rolls of film. Well, anyone could help me to deal with this problem? The pictures quality were not affected but I feel not comfortable with many small dot in my focusing screen.

-- David (knighthunter@hotmail.com), July 18, 1999

Answers

I had the same problem with my new camera. Be careful not to touch the mirror with anything. Get one of those cans of air from an electronics or computer store, and blow it into the camera. Do not turn the can upside down or the liquid inside will not be able to vaporize in time, and could get on the mirror, possibly damaging it. If the dust is up in the pentaprism, take the thin little tube that comes with the can, aim it up into the gap between the focusing screen and the pentaprism, and blow. If that doesn't work, you might have to remove the focusing screen. But this worked for me. Good luck.

-- Jim Meyer (jim_meyer@compusa.com), July 19, 1999.

David, I'm not trying to be rude, but you better get used to having dust in there. I have a Nikon F3, which is designed to allow for easy removal of the prism and the focussing screen, and I can never get it perfectly clean.

Be very carefull with the mirror. You might have some success with a very soft lens brush (or a small sable artist's brush). Don't use any liquid cleaners in there.

As you said in your question, picture quality isn't affect by the dust.

-- Geoffrey S. Kane (grendel@pgh.nauticom.net), July 20, 1999.


David, you better get used to the dust, as trying to removing dust in models which the focusing screen not designed to be easily removed usually end up with much more dust.

-- Eric Ung (ung@hongkong.com), July 21, 1999.

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