Originally posted by Lulerfly It will meter automatically in aperture mode right? On the K20D and K7?
No it will not, sadly. It will work wide open in Av mode.
If you want to use it on a recent body, the best way to do so is to set the aperture on the rign of the lens, then enter full Manual mode, and press the green button while looking at your subject. The camera will then make an exposure measurement, which will remain valid as long as you keep the same illumination, ISO and aperture.
After the first "measurement", it's actually extremely fast to use such a lens, you have nothing to do except shoot.