Mirror clean on an EOS 3?

Hello everyone.

Just picked kens myself up a new to me Eos 3 body. Everything looks in decent enough condition but the mirror is filthy. Looks like it could be from finger prints on closer inspection. Anyone have any idea on how to go about cleaning this? Don't want to break it while I can still take it back.

Thanks.
A.

Best to simply ignore it.
If you cannot ignore it moist a Q-Tip with alcohol (e.g. isopropanol) and very gently wipe the mirror with no pressure.
Repeat if necessary and finish with a dry one if necessary.

Try VisibleDust Swabs.
They're sort of like cotton buds (which I think is what you yanks call Q-tips), except they're flat and don't leave bits of cotton floating around.
OK, so they're meant to be for Digital sensors, but they work great on mirrors, they're flat and nice and gentle and don't scratch.

I don't recall if that model has a pellicle mirror or not (where the mirror doesnt move and some of the light passes through the mirror and some up to the viewfinder), but if it does, they can be ruined by careless cleaning. If it were me, I think I'd tell the buyer that you'd be willing to take it to a camera repair tech for cleaning, but if it's damaged, that it will be returned for refund. If that's not acceptable, if it were me, I'd return it.

Otherwise, I've cleaned "regular" mirrors by using a dab of glass cleaner on a clean NEW microfiber cloth without problems. They generally don't leave an oily film and they don't scratch. "Your mileage may vary."

binglebugbob said:

I don't recall if that model has a pellicle mirror or not (where the mirror doesnt move and some of the light passes through the mirror and some up to the viewfinder), but if it does, they can be ruined by careless cleaning. If it were me, I think I'd tell the buyer that you'd be willing to take it to a camera repair tech for cleaning, but if it's damaged, that it will be returned for refund. If that's not acceptable, if it were me, I'd return it.

Otherwise, I've cleaned "regular" mirrors by using a dab of glass cleaner on a clean NEW microfiber cloth without problems. They generally don't leave an oily film and they don't scratch. "Your mileage may vary."

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The EOS 3 doesn't have a pellicle, but the advice still holds, all the mirrors split the light paths to the viewfinder and the AF detectors, so clean carefully.

If it's a regular mirror, clean it. It plays no role in making the image. You probably should turn the camera mount side pointing down and blast it with some air to blow out dust and debris before you clean the mirror.

I've cleaned many mirrors. It's not a huge deal.

Thanks so much for all the replies, really appreciate it. My main concerns are around how delicate the mirror unit is and if cleaning could effect the AF points/detectors. Also as far as using a rocket blower/compressed air, is there not a danger of getting dust in the prism or focusing screen by using that, or do I now sound like an idiot?

Apjcphoto said:

Thanks so much for all the replies, really appreciate it. My main concerns are around how delicate the mirror unit is and if cleaning could effect the AF points/detectors. Also as far as using a rocket blower/compressed air, is there not a danger of getting dust in the prism or focusing screen by using that, or do I now sound like an idiot?

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The safest course of action if you are fumble-fingered with delicate mechanisms is to leave it alone and have the mirror professionally examined on a service bench. The mirror has no role to play with the AF points/detectors which are located at the top of the prism behind the prism base mirror (this is above the focusing screen — another place strictly off-limits!). EOS camera mirrors are fairly tolerant and can be cleaned with denatured alcohol and a microfibre cloth wrapped around a cotton bud (Q-tip) applied very, very slowly. NO FORCE, NO PRESSURE. My EOS 1N mirror has been cleaned many times over the 24 years I've had it with no ill-effect (these mirrors are back-silvered). If there is visible dirt or grunge on the mirror it is essential to remove this first before putting anything else on the mirror to do with cleaning). Ultra-fine make-up brushes (without make-up residue on them... ) are excellent but you're working with the very tip of the hairs, not the body of the brush proper). With blowers, people often get too enthusiastic and actually blow the shutter — just one vigorous puff of a stray blower will effect movement accuracy of the shutter, very especially the EOS-body versions which are duralamin-plated and hinged. If all this sounds just scary, take heart. I wrote-off an Olympus OM4 decades ago but applying JIFF (liquid scourer...!!) then cleaning up with a hankerchief. Needless to say the mirror (front-silvered and profoundly sensitive) was scratched and scarred beyond repair, all because I found a couple of specs of dust and didn't at that time have a clue how to remove them.

Lesson learnt.

The AF sensors of the EOS3 sit in the bottom of the body and "see" the image via a secondary mirror on the backside of the half transparent main mirror.
AF and MF Focus WILL be affected if you mess up the delicate mirror position.

If the mirror is a "first surface" mirror then DO NOT TOUCH It IN ANY MANNER. There is no protective covering over the reflective coating which scratches very easily. With ordinary mirrors the reflective coating is on the back of the glass and so protected.

A professional repairman can replace the mirror. This is usually required since acids in sweat corrode the mirror surface and no amount of cleaning will fix it.

I think all mirrors in SLRs are first surface morrors. I cleaned only one in a Minolta XD7 and generated no scratches (and no noticeable focus error) with the method I listed above.

Gerald C Koch said:

If the mirror is a "first surface" mirror then DO NOT TOUCH It IN ANY MANNER. There is no protective covering over the reflective coating which scratches very easily. With ordinary mirrors the reflective coating is on the back of the glass and so protected.

A professional repairman can replace the mirror. This is usually required since acids in sweat corrode the mirror surface and no amount of cleaning will fix it.

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+!

I think the OP should keep in mind that this is a purely cosmetic problem. The dirt on the mirror (and I doubt that there is a fingerprint etched in the silvering) will affect neither the picture on film nor the image in the viewfinder. All it can do is throw off the metering a tiny bit.

Thanks again everyone for your advice. You've all managed to make it seem totally easy and terrifying in the same thread! I'm going to give it a go tomorrow in the daylight and see how I fair.....