Many older digital SLR cameras do not have built-in sensor cleaning features, and therefore tend to collect a lot of dust. Photographers usually realize their sensor needs to be cleaned when little specs start showing up in their photos, but there is also a lot of dust that cannot be easily seen with the naked eye. Think your camera sensor is clean? If it hasn’t been cleaned in a few weeks, I bet I can prove otherwise with this simple test!
New digital SLR cameras are able to clean their own sensors with micro-vibrations, but older models are not so self-sufficient. Cameras such as the Canon 20D and 5D require the photographer to manually clean dust off the sensor. You can have this done at the factory, or take care of it yourself. Here is a quick test you can do in Adobe Camera Raw in order to find out whether or not your sensor is dusty:
- Open up a raw file in Adobe Camera Raw. Landscape photos are good subjects for this test, because dust has a tendency to show up prominently in the sky.
- Enter very high numbers for the “Blacks”, “Brightness”, and “Contrast” sliders.
- See lots of dust on your camera sensor.
Increasing the blacks and contrast helps bring out the dust, and pumping up the brightness counteracts the overall darkening caused by those first two adjustments, enabling you to see the dust that is present on your sensor. Here is a sample image:
First, here is how the image looks when processed normally:
Not too bad, eh?. Now, here it is with the settings described above, showing off all the dirt on my 5D’s sensor:
And if you think the dust is apparent in these photos, it’s even more so at full resolution. It may not be visible in the thumbnails, but at moderately larger sizes the sky is dotted with tiny dust specs.
The numbers I used were Blacks: 60, Brightness: 100, and Contrast: 50.
If this test brings out a lot of dust specs in your photo, it’s time to clean your sensor. If you do not feel comfortable doing so yourself, you can have Canon clean your camera professionally.
