I have been using the 20D for a couple years and decided to get a 40D for my primary camera. It arrived today and I did a quick operational check. So far it is doing everything as I expected. The only concern I have is that there is a - vibration? - when I trip the shutter. I am wondering it it is the sensor cleaning or something else. Also most importantl is the vibration going to tranlate to soft pictures? Has anyone else had this experience?

I just finished some more experiements. It's not the sensor clean because I did some test with start up and auto clean did not produce any feeling of movement at all. It appears that my 20D is faster, although not as many shots, on continuous mode. If Ihad to describe this feeling as a sound I would say a short buzz would be close. It seems to have something to do with the mirror movement.

Since all DSLRs have a mirror that moves up and down quickly when the shutter is released, a certain amount of noise and vibration is normal. THe amount varies from model to model, but doesn't necessarily correlate to image quality issues. It isn't something that generally causes blurring unless you're using telephoto lenses, in which case a sturdy tripod is advisable anyway. If you're worried about vibration blur in your images, go take some pictures and then look at them. You'll have a better idea of how well your camera works, and we won't have to use ESP to guess how blurry pictures you haven't taken yet will be.

Thanks for responding. I am familar with the mirror movement but this is something entirely different. I have used SLR's for some time and in the last few years have owned a 300D and 20D and neither of these units had this feeling. I am going to see if a local store has one on hand I can try out in the store. I think there is something mechanically wrong with this unit. I also so a post in this forum that suggest a way to lock up the mirror and shot. I think I will try that to see if it is a mirror movement or shutter movement problem. Thanks again.

The vibration may be more pronounced in the 40D because the mirror mechanism had to be updated to deal with the faster framerate. Just a guess.

And they have some of the quietest mirror mechanisms of SLRs in general. Listen to what happens when you press the shutter release of a 1D-MkII, especially at 8FPS. They don't call it a machine gun for nothing. Increasing the frame rate means a faster, more powerful mirror mechanism, which is going to make more noise and vibration. It's quite likely you're getting panicked over nothing.

I got my 40D a few weeks ago. The vibration you're feeling is normal. I believe it is because the shutter and mirror do not use springs but motors, which is a first in my experience.

I find the slight vibration instead of the normal clicking and slapping noises to be a far better feedback. It's much quieter and to me sounds much more durable.

I have experienced my 40d to be very silent on the shutter noise.
Almost as in rubber.

When I was meeting with Canon recently discussing their new equipment, they mentioned something that I'm not sure I understand, but it may explain the difference in the shutter feel/sound between the 20d/30d and then new 40d.

He said the opening curtain is now "electronic" instead of mechanical, the closing curtain is still mechanical.

I didn't ask him to explain this in detail, and I have no clue what he meant by that. He did mention the reason is live view, because the "opening curtain" may need to open and close many times when a picture is not being taken, the closing curtain only operates when you take a picture.

By electronic all I can think of is they are using some type of magnetic/motor system rather than a "spring" type system to open and close the first curtain.

Just to throw out a thought... could it be related to the IS feature? I know that my 1Ds gives off a sort of hum when the IS is activated. Maybe this is what you are feeling. Just a thought from left field.

Thanks to all, I guess I have become an untrusting nervous Nelly in my senior years. I was able to do additional testing today and everything looks normal. I did some shots using the same lens on the 20D and 40D and did not see anything unusual. I think the description above describes what is happening perfectly. I'll bet they get a lot of calls/emails though because during my research I saw this comment on more than one site. Another lesson learned is that there are 2 continuous shoot modes one same as my 20D and one High speed. Of course it took me awhile to figure that out too.