If you’re like most of us, sooner or later you’ll begin noticing little spots on your images caused by “dust” on the Canon 40D’s low-pass filter. It’s not actually dust as we think of it, but usually very tiny metal shavings which are caused by the shutter mechanism and by changing lenses.
Even with the “Dust Cleaning” features in the Canon 40D, some day you’ll find a particle or two that can’t be removed with an air blower. So you have two choices. Send your camera body off to Canon for a cleaning (which I usually do once a year or so) or remove the dust yourself using any number of methods.
I’m not going to make any recommendations on this issue but if you do decide to handle the task yourself I recommend getting in touch with the folks at VisibleDust. They are extremely knowledgeable, helpful and downright friendly. If your spouse or significant other is looking for a great gift, look no further. Just be sure to tell them which size sensor needs cleaning!