It was bound to happen sooner or later – i got dust spots on the sensor of my camera. It became very obvious over the summer when i was shooting landscapes with small apertures. Small dots that appear in the same place in every shot. Of course, it can often be corrected in post processing but that’s a pain in the butt.
So i did some research. The public opinion seemed to be to never touch the sensor. My Nikon D7100 camera has a sensor cleaning program. I tried that. It didn’t make any difference at all. The recommendation is to blow the dust away using a blower tool or compressed air. I went online and bought a Giottos rocket blower. I huffed and i puffed, but not a single dust spot disappeared or even moved. What to do? I called up my favourite camera store in town – Kameradoktorn. Always nice and helpful service there. The guy there told me that as the sensor gets warm, many dust spots will attach to it so hard that blowing them off is not possible. He suggested i bring the camera in for a cleaning, so i did. He spent quite a bit of time on it, using compressed air and sensor cleaning swabs and it came out clean and shiny as new.
Since it cost me quite a bit of time and money to get it cleaned, i have decided that next time i need a sensor cleaning, i will do it myself. Using the proper cleaning tools, it can be done. I will also run the sensor cleaning program in my camera regularly and use the blower to keep dust off my lenses. This is no guarantee however. If you’e using zoom lenses, they act like a bellows and will pull dust into your camera sooner or later.
I will not go into how you clean your sensor by rubbing it because i have not yet tried it and i know there are good tutorials out there on how to do it. Here’s one that i found pretty good.
How to check your sensor for dust spots
OK, so how do you check if your camera has dust spots on it’s sensor. It can be done in a few simple steps. Bring out your camera and using auto-focus, focus on something close. Then turn off your auto-focus so that it’s locked on the close subject.
Now set your camera to aperture priority mode (A on a Nikon), set the aperture to the largest number available. It should be something like f22 or f32. The reason you want a small aperture, is that you want as deep a focus as possible. You will essentially be taking a picture of the surface of your sensor here. With a larger aperture, any dust spots on the sensor will be out of focus and you will not be able to see them.
Next, you want to aim your camera at a bright subject and take a picture at whatever shutter time the camera chooses. Aim you camera at the sky on a bright day. You can also bring up an empty document in a text editor on your computer at take a picture of your bright white screen. Motion blur is not an issue, because you’re essentially photographing your sensor. It’s actually a good idea to move the camera around during the exposure, so you get an even light with no details in the picture.
Now it’s time to start looking for dust spots. Open up your picture in the camera display and zoom in. Move the zoom area over the entire picture. If there are dust spots, you should be able to see them.
If you are a lucky owner of Adobe Lightroom (you should be – it’s great), there’s an even better way to see dust spots. Import your photo into Lightroom and open up the develop module. Choose the spot removal tool (shortcut key Q). Now, under the photo, you see a checkbox with the text “Visualize spots”. When you click this checkbox, Lightroom shows your photo as a black mask with any spots shown in white. Here’s what mine looked like before i had it cleaned: