How well does the sensor cleaning function work?

Is the senseor cleaning system in the 40D the same as is in the 400D (XTi)? Does it work? If so, to what extent?

there's actually a post like this already just last week i believe. can't remember title and no time to look for it....
some people say it works...and i would say it's the same as the 400d.
i had mine switched off coz i don't wanna run it down too much as i switch on and off a lot at the moment whilst i'm getting to grips with it. (only just gone past the 200 actuation mark last night)

I haven’t had my 40 long enough to judge but I also have a 400 for about 10 months now. The system works by mounting a ultrasonic transducer to the low pass filter glass. It’s basically a small speaker. Turn it on and it vibrates the glass at a high frequency. In practical terms, I have had to clean the 400 less than either the 5D or the 350 but it does not eliminate cleaning all together. It seems to handle the dust a blower would have gotten rid of but the sticker stuff still accumulates and every once in a while a wet cleaning is still needed.

Hi gjl711,

Thanks for explaining. Do you just let the cleaning system work when the camers is turned on and off or do you manually do it?
Is there any harm or reason not to just have it do it on power up and down?

Well I don't have the 40D but I have 1D MK III and the 2 sensor systems are similar. After 3,5 weeks in dusty africa I think the sensor cleaning system did a good job. Sure there are dust on my sensor but it is not at a level that I am going to do anything about it anytime soon.

Thank you Tommy,

The bottom line is that it does work? It may not do a complete job but with little specks that would otherwise be blown out with a Rocket Blower, you find it compres to that?

TMR Design wrote in post #4011279
...Do you just let the cleaning system work when the camers is turned on and off or do you manually do it?
Is there any harm or reason not to just have it do it on power up and down?

I have it set to the defaults, that is it cleans on power up and power down. The transducer uses so little power that you might loose maybe a shot or two in battery life if even that. You can also override the cleaning if you need the camera fast. On power up if you press the shutter the cleaning stops.