i have a small scratch on the prism,,,you can notice it easily through the viewfinder.has anybody had this affect metering or photo quality in any way if you have the same?

-- Steve Lanier (slanier@vci.net), November 04, 2001

Answers

sorry i forgot to mention this is on a eos 7

-- steve (slanier@vci.net), November 04, 2001.

Dust or marks on the focusing screen or prism won't cause meter or AF problems.

How did you scratch the prism? Did you remove the focusing screen and accidentally scratch it? Did it come this way when you bought it? If it wasn't scratched when you bought it and you didn't perform disassembly, probably the mark is on the underside of the focusing screen. In fact, if you weren't attempting a repair or cleaning, there is no way of scratching it. In that case, it's probably a particle that blew in.

Dust, hairs, tiny bugs, etc., have found their way into my SLR many times. If the mark is a little blurry, it's on the lower surface of the focusing screen and may be blown off with a bulb blower. Don't use canned air or your breath (you'll make it worse!!!). If the mark is sharp, it's on the inner surface of the focusing screen and you should taken to Canon for cleaning if it bothers you (the EOS Elan 7 has a non-removeable focusing screen, at least for non-techies).

-- Puppy Face (doggieface@aol.com), November 04, 2001.

If you can see it clearly then the scratch is probably on the plastic lens under the prism. That's what usually gets scratched. It is easily replaceable by a competent technician. The usual wisdom says, "Never touch it! Not even with a soft cloth. Don't try to clean it with anything more stiff than a soft brush or a soft puff of air." Actually it's not quite that tender, but you get the idea.

Unless the scratching is very bad it won't effect metering at all & even then it would be only a small change. In any case there will be no effect on the image since this is blocked off when the picture is being taken anyway.

-- Jim Strutz (j.strutz@gci.net), November 04, 2001.

thanks for the response guys! i feel a little easier,,,,i am ashamed to say that i scratched the prism brushing dust off with a soft bristle brush. i still dont know exactly what happened,,,, i know this,,,never get near the prism unless you know exactly what you are doing!!!!!!!!!!

-- steve (slanier@vci.net), November 08, 2001.