Originally posted by stevbike The Pentax K-m has the aperture control via the camera body control wheel on the back of the camera. It took a bit to get used to using it but I like the way it works now. I think all the newer Pentax digital camera bodies work the same way.
I think he is probably wondering about film bodies (posted on film camera section).
The short answer is that any body supporting programmed or shutter priority (Tv) auto-exposure can be used with lenses lacking an aperture ring in those modes. For the early models, that means indirect control with the body governing the aperture. Direct control of aperture from the body is limited to models having a control wheel for that feature. See Bojidar Dimitrov's Pentax K-Mount Page for a full listing including features:
Pentax Camera Bodies
The series you are interested in are: A, P, and all of the AF bodies.
Steve