Originally posted by demp10 Best way to use an adaptall lens is using the aperture ring and the green button, or use one of the cheap adapter without an aperture level in AV mode, that essentially behave like an M42 manual lens.
It's well-known that "aperture ring and green button" metering with M lenses is not accurate, especially for K10D and K20D. K7 and K5 are slightly better, but still far from accurate.
The smaller the aperture, the more pronounced the overexposure error.
Stoped-down lens and Av mode is not much better either.