Originally posted by Blue You ignored post 40.
Actually, it was because of post #40 that I felt a general clarification would be helpful. I am still not sure what is meant by "aperture priority via program mode".
Historically, Av mode has been the easier type of exposure automation to support since it generally requires no physical coupling between the lens and body. The major exception being where the lens has no aperture ring. In that case, (obviously) the body must support both the coupling to set the aperture and a user interface for that purpose. So yes, "Aperture Priority via the body requires a body that can control the aperture"...duh!
In general, I feel that it is best to avoid drilling too deep on these sorts of things. The basic definitions are usually quite adequate. How a feature is implemented is often TMI (too much information).
Steve
(Has this thread gone deep enough down the rat hole yet???)