Originally posted by bdann The camera, as you said, doesn't know what aperture you are using, however it does know how much light is entering the lens and it will set the shutter speed accordingly.
Setting the camera in Av mode, selecting your desired aperture, and letting the camera select the shutter speed is no different than shooting in manual, selecting your aperture, and setting the shutter via the green button...at least not that I have found. I think some experimenting is in order when I get home...
You can do that with A lenses but not M or K lenses. With M and K lenses, if you use Av mode, the camera will only meter as if the lens is wide open. I guess you can then work out what the proper shutter speed should be depending what the actual aperture is.
If you want the camera to calculate the correct exposure for you with M/K lenses, you will need to be in the M mode. First you will need to enable a setting in the Menu (sorry can't tell you which one, don't have my manual nor camera here at work). Then:
Set the camera mode dial to M.
Select the aperture you want to use.
Compose your shot.
Press AE-L button (this is on DS, not too sure about K10D)
Press shutter
By the way, there has been a few reports about K10D will under-expose with M/K lenses. But this seems to be able to be corrected if you swap the focus screen with one from DS.
cheers
Kenny