Is it normal to have tiny black dust spots in the viewfinder of a DSLR?

Question

After shooting for about a month with my new D7100 I discovered some dust in the viewfinder / focusing screen or the prism area.

The dust is not visible in the images and it does not have any effect on image quality because the dust is not located on the sensor. It's only visible when looking carefully into the viewfinder and you can see a few tiny black spots on the edges of the viewfinder screen. On the Internet this particular issue seems to be quite common.

Is this a normal thing and something I have to get used to when shooting with my D7100?

Answer 1

Yes completely normal and nothing to worry about.

As you are aware all SLR / DSLR cameras have a prism / mirror / eyepiece, which can collect dust just as easily as any other part of your camera.

I can only assume that you do not keep your D7100 in a particularly sanitary conditions - as my D70, D300 and D800 have never suffered with viewfinder dust to a noticeable degree, I am not a clean-freak, but I always keep my camera body free of dust and in a closed camera bag.

The only thing that I would really worry about is the fact that there is now dust INSIDE your camera body, and if it continues to get in at the same rate, it will soon find its way to the sensor, which is where it will start to cause image quality issues.

Answer 2

I've had that problem on my 400d. If the spots do not show up if you photograph a white wall with at F22, you have dust on either the focus screen or the viewfinder glass. First clean the glass and see if the spots are gone. Then check if your camera has a interchangeable focus screen. Then you can take it out to clean it. I believe yours does not, so you need to dust blow it (with a bulb blower) to see if you get lucky and blow the dust away.

Answer 3

Years ago, I used the prime lens on my DSLR and never used to change it, thinking I would never get the dreaded dusty focus screen. And yes spots on the focus screen too. So it's not a zoom lens issue only or removing the lens issue only. I remove it every day now. What I started to do years ago was after every day of shooting, I do the vacuum trick. This is simply removing the lens and holding the camera body so it faces downward. I then use the vacuum tube and suck out the dust/debris. (Do not try to hold the vacuum tube so close to the body's lens mount you want a tiny gap so not to suck out the shutter blades. Pretty simple. I still get some tiny black spots that won't budge but I live with it, and do not try to Q-tip or rub on them. My focus screens seems to say a bit clearer.

Never, I repeat, never rub the focus screen with Q-tips or microfiber cloth. This is for a few reasons. Nikon for some strange reason uses some sort of micro fuzzy blackout in the black box, this micro fuzz detaches from the black box and ends up on the focus screen when using a microfiber cloth. The Q-tip leaves cotton on the focus screen and that's a huge pain trying to remove that as it gets pinched in the focus screens locking tab and frame. And the microfiber cloth will scratch the focus screen as it is soft plastic.

I learned the vacuum trick from Nikon. I never use any thing that blows in the body either, This just forces the debris onto the shutter blades and onto the sensor when the open and close. I shoot f/16–22 a lot so I don't risk it.

The dirty focus screen is easy to remove, but I also don't recommend this either because when reinstalled there will be debris in-between the focus screen and focus point screen (Yes there is two screens a focus screen and focus point screen before prism). I also extend my zoom lenses and vacuum out the lens too.