Image plane digital (non-film) autofocus

Contax had a nifty idea with their AX camera body, which brought autofocus to loyal users who had accumulated great and costly Zeiss manual focus lenses. The AX autofocuses by moving the film plane, rather than lens elements. Downsides, however, come in the form of the bulk and heft of a body designed to move film back and forth precisely while it's attached to a spool on each end.

Such problems vanish, however, when solid state photoarrays replace film, as in modern digital cameras. Digital image plane autofocus could vindicate the innovation of the AX, letting users of whatever system (call me, Nikon!!) keep their sharp old motorless lenses for autofocus use.

Secondary advantages: 1) in moving a light photoarray, rather than heavy glass, focus response could be quick and energy- efficient; 2) lenses set at infinity would then handle like internal-focus, rather than more awkward helically extending AF lenses; 3) lenses set at close focus, with the image plane set as far back as possible, could yield extended close focus range; 4) with AF lenses attached, perhaps image plane and lens movements could be combined for even faster focusing than either alone would allow!

Ok, Nikon, do your magic.