Stu wrote:

No offence Bill, as I know you know your stuff, but that dust removal system
doesn't cut it for me. Sounds like a lame gimmick. Where exactly does the
dust go???

Supposed to be a sticky strip below the sensor that 'catches' the dust.

As for a 'gimmick', I just posted results of a test on the dust removal
options on the 400D, which are at best mixed. You can read the details
here ... http://members.aol.com/bhilton665/tests/dust_400d/

However, never mind that, I have never had a problem with dust on the 20D
and I don't need use a blower on the sensor regularly to prevent this.

On the site above I describe a rigorous way to check for dust ... if
you run this test (close focus at f/32, white subject over-exposed,
view at 100%) and have no specks at all then I would be surprised ...
give it a shot and see.

As for the 20D, we have a 10D and it is also relatively dust-free
compared to the larger sensor bodies. Dunno whether it's the smaller
sensor or if the glass is coated differently or what, but it seems like
it can go 6 months between minor cleanings. The larger sensor bodies
seem to need cleaning after a week's worth of shooting (except in
Africa, which is a special case).

Although I have not shot in Africa. Saying that, if you have the bodies you
have, then you wouldn't have to change lenses very often.

In Africa the 1D M II is basically for the 500 mm lens but I'm always
changing between the bare lens and the 1.4x and the 2x converters, so
maybe a dozen swaps in a 3 hour morning shoot ... the other camera
usually has the 70-200 but occasionally I need to put a 1.4x on it or
switch to the 24-105 or, rarely, to the 300 f/4. So maybe 4-6 lens
swaps per morning with this one.

The only true solution to dust on the sensor is a little care when changing
lenses and a weather sealed body/lens.

I don't think weather sealing helps that much given that the 1Ds and 1D
M II we use are both weather sealed and yet are much more prone to dust
than the 10D, which isn't sealed ...

Bill