Originally posted by paperbag846 AV mode can only be used if a lens is in A mode, and I never had exposure difficulties in A mode.
Actually Av can be used with M42 lenses and then JonPBs test can be carried out but only with M42:
Originally posted by JonPB For someone who is interested in testing this, take a pre-A lens, or an A, F or FA lens set to apertures other than A, and use Av mode in a controlled and constant lighting environment; for each stop of adjustment on the aperture ring, the shutter speed should double or halve.
With K-R I doubt nothing has changed since erlier bodies and if you use AV with M42 lenses you get exposure errors if the contacts on the mount are not shorted correctly. I have to dial in +1.5-2EV with my K200D with certain M42 lenses to get exposure right.
It'd be nice if someone could tell me it isn't so