To Paul Bestwick
Hi Paul:
Somebody else noted you should be stopped down to the fullest extent possible and the comment is right on. I disagree about the additional PP to "enhance" the dust bunnies. IMO shooting a cyan sky with my widest lens fully stopped down at the proper exposure for the sky is good enough; if I don't see the dust set against a properly exposed sky background the sensor is CLEAN (from my perspective).
I use Pec Pads, a spatula of the proper size (from the Copperhill guy), and Eclipse solution; this setup does the "wet cleaning" job for me. For dry cleaning (i.e. hand held blower) I use a rectal syringe purchased from Walgreen's Pharmacy - please don't laugh, it is a big bulb that moves a lot of air AND it starts life clean as a whistle because of the intended application. By "clean as a whistle" I mean as delivered to the pharmacy there is no debris inside the rectal syringe bulb that will add more garbage on the sensor than you are trying to blow off.
Now here is the interesting thing about dust/dirt/lint/FOD accumulating on the sensor. From my experience it appears to be more a function of the camera body than the conditions under which a lens change is made. I have three bodies, 10D, 30D, and 1DmkII. I have not had a full year of experience with the 30D so I will withhold comment on that body.
Okay, the 10D is wonderful. If and when I see the rare dust bunny on my 10D the hand held blower does the job and the camera STAYS clean for "long" periods of time (note, I rarely change lenses to minimize opportunity for dust bunnies).
My 1DmkII is a real PITA; it always gets dirty and no amount of hand blower action will clean the sensor. I ALWAYS have to wet clean that body to get it completely clean (and I mean completely). Now, on occasion, after about four or five shots following a perfect cleaning job (i.e. zero spots) a dust bunny in the form of lint debris (probably from a Pec pad) may appear and the hand blower will remove this easily. Now for some really bad news - within one week of shooting and "without removing the lens" some "difficult" dust bunnies will appear on the sensor. By difficult I mean they require a wet cleaning, nothing else will work. One thing I've noticed about the "difficult" spots is they are very small compared to what I will call typical dust bunnies. I think, but I'm not absolutely sure, the difficult spots are the result of some sort of "dry" lubricant flying around from the combined motions of the shutter and mirror (BTW, I always reserve the right to be wrong). I suspect the "dry" lubricant, if that is what it really is, may be coming off the shutter mechanism or mirror hinge (actually I shouldn't guess because I really have no clue) and once removed, the air moving around from the mirror flopping around at 8+ frames per second is enough to move small mountains in the form of dust bunnies past the shutter and all around the sensor chamber area.
Please keep in mind my own experience does not "necessarily" mean or even imply that 10D bodies are better than 1DmkII bodies from the standpoint of FOD accumulating on the sensor. OBTW, FOD stands for "foreign object debris". Anyway, when I shared my experience with another photographer friend his experience did not track mine at all. My friend told me his 10D was a dust magnet and very difficult to clean while his 20D was a real charm. I'm sharing this information to make to make you (any other readers) aware that dust/FOD issues "may" in fact be a function of "camera to camera" variations rather than "model to model".
Normally I don't get bummed out over garbage on my sensor because it is easy to clean (i.e. even the wet cleaning, a relative PITA compared to dry cleaning, is still a simple operation). However, I was once on a one month trip to shoot Arches and Canyonlands National Parks and wouldn't you know it but I forgot to pack my sensor cleaning box (I keep everything to do with sensor cleaning in one small box). To make matters worse I didn't clean the 1DmkII before I left thinking a sensor cleaning job would be the first thing I do once I get into town. Well, I came back home with about 30 GB worth of dusty skies and needless to say I wasn't happy with Canon, my gear, or myself for screwing up in the first place.
After my sad experience at Arches (which was pretty much my own fault) I can sympathize with some folks out there that are unhappy with the sensor dust situation and Canon's lack of attention. I don't think Canon can actually do anything about it, not today and not tomorrow - IMO dust will be with digital forever. What I expect from Canon is to inform and educate the user public regarding how to best clean the sensor "on our own" BECAUSE the hand blower does not work for most folks. Sending a camera to Canon for cleaning every month is not an option (even if the cleaning was performed at no cost); this is not an option "not" because shipping and receiving a clean body is an expensive PITA, but because even Canon can't clean the sensor all that well.
So, now you have my rather long take on sensor FOD and cleaning.
Regards,
Joe Kurkjian