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I just bought my D70 from Sam's Club. It was a display model, and the display assembly does not allow the back of the camera to be opened. However, when I opened up the front and looked at the mirror with a bright light, I see that there is a pretty significant size of a dust particle on my mirror in the SLR. I tried the rocket on there to try and blow it off, but that did not work. I have seen many links online that I googled, and they say use a Q-tip. That seems a little abrasive to me.

I know Eclipse makes swabs and pec-pad and the optic cleaner. But that is for the sensor right?

I do not want to damage the mirror, so, what do you suggest?

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  • \$\begingroup\$ Closely related: Will cleaning up the reflect mirror under strong sunlight damage the sensor? \$\endgroup\$
    – scottbb ♦
    Commented Nov 7, 2016 at 4:50
  • \$\begingroup\$ What do you mean by the "back" of the camera? The mirror is accessed by the opening on the front of the camera when the lens is removed. \$\endgroup\$
    – Michael C
    Commented Nov 7, 2016 at 5:49
  • \$\begingroup\$ Clean a DSLR Cam: youtube.com/watch?v=lrdkFXsr5Us \$\endgroup\$
    – user58160
    Commented Nov 7, 2016 at 15:15
  • \$\begingroup\$ Sorry, you are correct. I meant the front. \$\endgroup\$
    – Gunny Winaz
    Commented Nov 7, 2016 at 16:47
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    \$\begingroup\$ Is the dust disturbing you? The surface of the mirror is out of focus, so you'd really need a huge amount of dust to get noticeable degradation of the image quality in the viewfinder. If you see dust, they're most likely on the focusing screen, not on the mirror. \$\endgroup\$
    – Matthieu Moy
    Commented Nov 10, 2016 at 10:39

3 Answers 3

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Just don't.

The coating on the surface of your camera's mirror is the most fragile piece of your entire camera that is accessible without taking the camera apart, probably followed closely by the underside of the focusing screen located just above it. The mirror should never be touched on the surface. Unlike most mirrors in other applications that have the reflective coating on the back of the glass, the mirrors in cameras have the coating on the front surface and it is easily damaged. At most, use an air blower to gently knock dust off of the mirror.

Trying to clean the mirror will likely result in scratches that are worse than the dust you wish to remove. You can also easily wipe part of the coating off, reducing the reflectivity of the mirror. Anything that changes the reflectiveness of the mirror or the transmissive properties of the focusing screen can also affect the accuracy of your camera's light meter, which is located above the focusing screen. The light measured by the meter must first reflect off the mirror and pass through the focusing screen.

There are a few specialty service providers that can use a special chemical process to clean the mirror, but it is expensive even before the shipping charges and insurance add insult to injury. Even many factory authorized service centers will replace (using very delicate handling procedures) rather than attempt to clean a reflex mirror in the camera's light box.

Any DSLR camera that has been used for any length of time has a little dust on the mirror. The best way to deal with it is just to ignore it and keep on shooting. After all, even factory fresh lenses have a little dust in them as well. Unlike the mirror, that dust is actually in the light path of the image as recorded by the camera.

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  • \$\begingroup\$ I have another question. I just bought a 85mm lens on Ebay. He said it is in "Like New" condition. I have heard of people talking about "fog" in the lens. How do I know if this is happening on this lens I bought. If it has fog, I want to return it right away. I am always leery about buying lenses from Ebay. I won it for a great price late at night. I hope I didn't make a mistake. \$\endgroup\$
    – Gunny Winaz
    Commented Nov 7, 2016 at 17:00
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    \$\begingroup\$ You should post your other question as a new question, rather than a comment to a different question. \$\endgroup\$
    – Michael C
    Commented Nov 7, 2016 at 23:10
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    \$\begingroup\$ How likely is it really that a soft brush would scratch the mirror? Have you seen that happen? There's no doubt that first-surface mirrors like the one in an SLR are more fragile than ones coated on the back and protected by glass, but I've handled large pieces of first-surface mirror (they're great for kaleidoscopes) without any problem. If they're really that fragile, how do they stand up to tens of thousands of shutter activations with no damage? \$\endgroup\$
    – Caleb
    Commented Nov 8, 2016 at 14:28
  • \$\begingroup\$ It's not just scratches. It is the thickness of the coat, which affects the reflectivity. Every pass with a cloth removes a bit of the aluminum coat which is very soft. Tens of thousands of shutter activations don't allow anything except air to come into contact with the reflective surface of the mirror, all physical contact is only with the frame that holds it. \$\endgroup\$
    – Michael C
    Commented Nov 8, 2016 at 23:34
  • \$\begingroup\$ dgrin.com/showthread.php?t=174679 \$\endgroup\$
    – Michael C
    Commented Nov 8, 2016 at 23:51
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Personally, if the dust doesn't affect the actual (digital) shot, I won't bother with it. There are many places inside that dust can get it but doesn't affect the photo. Only if you're certain that the shot is affected should you consider getting rid of it. To make sure, shoot a white wall at very small aperture.

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    \$\begingroup\$ Dust on the mirror can never affect the image -- it's just annoying to look at in the view finder. \$\endgroup\$
    – Caleb
    Commented Nov 8, 2016 at 14:30
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I have used a brush made for mirrors and and sensors with no problems.I have used it on mirror and focus screen .First you have to spin brush or blow air through the brush bristles to give them a static charge to attract dust. Google arctic butterfly.

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