Originally Posted by janosh
Looks like "Av" (aperture priority) may be the best bet for me (mixing M and Limited lenses) because that works as well with both types, and the process makes K20D much more like film camera than "M" ...
"M" does allow more complicated setting process, but it doesn't necessarily improve exposure and it doesn't seem as intuitive... "Av" seems more intuitive, doesn't imply as much peering through the finder at internal readouts as "M" does...Pentax and everybody else, save Leica, is badly designed in this respect...knobs like Leica's are often better than readouts because they can be set by touch, without even looking.
Obviously I'm new to this setup but I'll have had a lot of experience by Monday..big doin's over the weekend: Matachine dancers.
Using Av on an M lens will only let you use the lens wide open. M is the only way to use any other apertures at on an M or K lens. On an A lens, yes, go ahead and use Av, it will be easier.