Good question. This amounts to superstition, but I had heard (maybe through this group) that the CMOS sensor retained a surface electrical/electrostatic charge that attracted dust if the camera was powered on and lost that charge if the camera was shut off.
Is this true? I don't really know, but I do know that I have never cleaned the sensor in my 20D (I've owned it for a little more than a year and I bought it used) and I just checked and I can't find any dust in the images. If it was more difficult than just shutting the camera off, I might not do it. But it's so easy, I do it almost every time. There are worse superstitions to follow. Mr. Bill > Why do you make sure the camera is shut "off" whenever you change lenses? > Doesn't this camera have a mechanical shutter? * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
