Sunday, May 24, 2009

A Much Needed Cleaning

I congratulated myself earlier today on having had my camera for a whole year now, but in that time I've neglected some of the maintenance and upkeep on it. Case in point is a good cleaning of the image sensor. The Rebel XSi has a built in image sensor cleaning function, but it only forestalls the inevitable cleaning process. Each time you change a lens, a little bit of dust gets into the inner chamber of the camera. Some of that gets past the internal mirror, lands on the image sensor and sticks. Some of what gets that far inside is shaken loose by the automated sensor cleaning that activates each time you turn off the camera, but the nastiest stuff sticks and never lets go. After a while, you start to notice dark spots in your pictures under certain lighting conditions, especially against open backgrounds like clear blue sky. I knew it was a problem that needed addressing before I went to Washington, DC, and I tried to fix it in a hurry, but I didn't do a good enough job, and I saw spots on every single picture I took while in DC. So this afternoon I sat down and did the job correctly. The picture above is an image of my sensor before I touched it, heavily tweaked and processed to show you the gunk on the surface. (I think those streaks are dust on my computer monitor, actually, not the image sensor, but the black bits are in my camera.) The photo below shows the after version of the same image, with most of the spots gone completely, and the ones that remain are extremely small. Certainly worth the time it took. I only wish I'd done it right before my trip.

I had to do this with my last camera as well, only I waited much longer and wound up with many, many more spots before I addressed the problem. Click here for before and here for after images of that time.

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