One of the horrors of owning a DSLR and using multiple lenses is the dread of getting dust on the camera sensor. In small amounts it’s visible whenever you shoot using a small aperture like f/22 but if you leave it go too long you’ll see round smudges show up on your every day snaps at f/8 or f/4 too.
This video describes part of the process I go through when I clean my camera lens. A Nikon body is used in the video but the method is similar for Canon and other manufacturers. I only have a blower and soft brush but they have served me well over the course of the last decade.
Cleaning the sensor is risky. It’s a sensitive piece of electronics but there’s an infrared filter in front of it and that’s what you’re really cleaning. It’s sturdy and tough but if you pushed too hard on it you will scratch it. I’ve never scratched the sensors of any of my cameras though so I don’t worry too much about it as long as I’m careful.
After blowing and wiping the dust away you should do the same with the inside glass of your lens. It’s likely that’s where the dust came from in the first place.
Once I’ve rebooted my camera I’ll test the sensor by doing the following:
- Grab a sheet of clean white paper.
- Set the lens to manual focus, the camera to shoot RAW, and change it to aV (or A) mode to change the aperture to f/22. If you use any exotic shooting styles reset them to standard.
- Prop the paper on a shelf in clear light.
- Shoot the paper. You don’t have to worry about it being a long exposure and camera shake. The dust on the camera sensor won’t move!
- Examine the picture on the camera LCD, zoom in and you’ll see any remaining dust particles as black dots. They’ll look like the images below.
- Repeat the “mirror lockup, clean, check” cycle until you’re happy with how much dust is left.