Best Method for Cleaning SLR Mirror?

[pvdhaar]

The whole trick in cleaning silvered surfaces is to make sure that you're wet-cleaning it to avoid scratches. It's a bit like washing your car; use lots of water and soap. I've cleaned SLR mirrors using the fluid from a sensor cleaning kit, and that worked without damaging them.

 

[Chriscrawfordphoto]

I wouldn't advise it: Sensor glass is relatively hard compared to a front-surfaced mirror.

I've used sensor swabs to clean the front surfaced mirror inside a Polaroid SX-70 (the folding SLR version) with no problems. I use the Eclipse sensor cleaning solution with them. It works fine, no scratches. Unlike the mirror in a 35mm or medium format SLR, the mirror in the SX-70 is part of the image-forming optical path; damage to it would degrade image quality. Mine works perfectly.

 

[Benjamin Marks]

As I read through this thread, I realized that since I started making photographs forty years ago, I have never cleaned an SLR mirror. And none of the cameras I own have ever had their mirrors cleaned, as far as I know. They can be quite dusty, and still transmit all the light that they need to do make your camera's focusing system function.

If you really must, I would wet a brand new lens cleaning cloth with your cleaner of choice and drag it across the front surface mirror with NO pressure behind it. QTips are too abrasive in my opinion. Better yet. See if you can convince yourself to ignore the crap on your mirror and just take pictures.

 

[Chriscrawfordphoto]

As I read through this thread, I realized that since I started making photographs forty years ago, I have never cleaned an SLR mirror. And none of the cameras I own have ever had their mirrors cleaned, as far as I know. They can be quite dusty, and still transmit all the light that they need to do make your camera's focusing system function.

If you really must, I would wet a brand new lens cleaning cloth with your cleaner of choice and drag it across the front surface mirror with NO pressure behind it. QTips are too abrasive in my opinion. Better yet. See if you can convince yourself to ignore the crap on your mirror and just take pictures.

A dirty mirror can affect metering accuracy by reducing the amount of light reaching the metering cells. On most cameras, these are in the finder. In some, like the Nikon F3 and the Olympus OM-4, they're in the bottom of the mirror box and depend on light passing through a semi-transparent part of the mirror. In either case, a clean mirror is needed. In addition, AF cameras focusing sensors look through a semitransparent mirror, too. A dirty mirror can make autofocusing slower or less accurate.

 

[monopix]

Kimwipes folded over to make a pad and held in round nosed tweezers (the pad should cover the end of the tweezers) then apply some non-alcoholic spectacle cleaner to the pad. Wipe. Dispose of the pad and repeat as many times as necessary. If there is any sticky goo from deteriorating mirror foam then use IPA just in that area first. You can use IPA over the whole mirror but I find it evaporates too quickly and leaves a residue. A couple of tips: a few wipe marks won't have any effect so don't get too fussy and, unless you have a very steady hand, cover the focus screen with some cardboard cut to fit first.