In article .com,
phk wrote:
I've been reluctant to switch to DSLR because of the potential
problems
with dirty sensors caused by the ability to remove the lens.

Is this a real problem with DSLRs, or not as bad as it seems. It
appears that Canon recommends use of a hand-held blower for dust
removal, but I wonder whether that actually works. Dust is often
tenacious and bonds itself to surfaces in ways that are resistant to
simple blowing. Maybe the best example is my eyeglasses. Once they
get dusty, only windex will clean them thoroughly.

Plenty good advice and observations here. Let me add:

The big blower has worked well over the year I've had a 20D, and the
half-year I've had a 350D/RebXT: prior to changing lenses I use it to
send the dust away from the outside of the camera and of the lens
mount before opening either. Keep the vulnerable surfaces/openings
faced down, to enlist gravity as an asset.

When the 20D (thrice, so far) or the 350D (twice) require dust removal
from the sensor, I do all the exterior blowing, let the dust settle,
and open the camera, close the lens, blow out the camera, lock-up the
lens, blow out the sensor cavity and close it all up. All the blowing
with camera open is with the opening facing down.

Typical suspenders-and-belt mode: I am equipped to use brushes and pec
pads, but haven't met the need, yet.

As has been said, dust on the sensor is real and a concern, but not
much bigger a one than dust or fingerprints on external lens elements.

--
Frank ess
"You know my method, Watson. It is founded upon
the observation of trifles."
—Sherlock Holmes—