Exposure Compensation

[chef57]

I wonder if anyone can help me. I have a canon 40D, I have read the manual about Exposure Compensation, it tells me to press the shutter button half way down and turn the dial at the back of the camera, when I do so it move the exposure level indicator, but it also alters the shutter speed. The thing is I get the same effect just turning the dial without pressing the shutter button. I use to have a canon 350D and you could alter the exposure without ajusting any of the other setting, why does the 40D not do the same. Can someone help me please.

Steve

[paulmag]

By half pressing the shutter release you take a reading and the dial just sets the compensation. Quick and easy.

The shutter speed will alter as that is what you are telling it to do which is either increase or decrease the exposure which can only be done by altering the aperture or shutter speed to accommodate the offset.

If you have the camera on AV (aperture priority) then the shutter speed needs to adjust by the offset otherwise it isn't going to make any difference.

[chef57]

Thanks for that Paul, I thought my camera was playing up, because you dont need to press the shutter button half way to alter the expsure compensation slider it does it anyway. And that is what I couldnt understand, the manual dosnt really tell you anything.

Thanks again
Steve