I've been troubled by this for a while, and it just gets worse... Whenever I look through the viewfinder of my D40, I see what seem to be little dirt spots. At first there were 2 of them, which I tried to blast out with an air compressor, but didnt work. Now theres about 7 or 8 in there that are smaller than the previous two... I dont want to touch anything inside the camera... How do I go about cleaning this off? They dont affect the quality of my pictures, it just bothers me that they're there. Also, how do you all go about cleaning the viewfinder glass?

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I am not sure which type of compressed air, but most are not good and leave residue inside the camera. I recommend using one of the rocket bulb type of blowers instead.
RUF

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Ted Rufus Ross

Nikon D200, but I am not married to it.
New Toy: Canon G7

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To tell you the truth... you cant, you have to take apart your camera just to get those dust off! or you can send it to the manufacturer and let them service it...
Now for the outside part of the viewfinder I use cotton buds and a lens cleaning solution.

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the dust you see is trapped inside the viewfinder.. I have one on our 20d and yes it bugs...

You can use compressed air, where people fail on using those is they tend to shake the can and use it on an angle,....

Do not shake the can and use it on a flat surface or hold the can totally vertical.

Try blasting near the view finder focus knob.

I use a Giotto Rocket Blower , a large one and it keeps the dust in check on my 5D and %D's are notorius for Dust, Mine came from the Factory with dust in it, and even when the sensor is dust free I still see some in the viewfinder.

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My Gallerys at :www.dale.zenfolio.com

Si Vis Pacem, Para Bellum
"If you seek Peace, Prepair for War."

For general cleaning I'd suggest using a clean new microfiber cloth
and vaccum/suction rather than q tips and blowing/canned air.

For this particular problem,Nick mentioned blasting air at the focus dial.

You may get better results, still, by rotating the dial with your thumb while you blast the air
into the focus dial assembly.The space around the dial is like an open window into
your view finder- that's where the dust gets in from.