They why is the same reason other manufactures do it. Glass is heavy little motor in body isn't strong enough to make it fast. So add motor in Lens. Nikon and Canon have been doing this since the late 80s
On Oct 14, 2014 8:00 PM, "James Schenken" <jds@xxxxxxxxxxxxxxx> wrote:
Some of the lenses were made with internal motors and are labeled DA lenses. They seem to be backward compatible with Pentax bodies with the builtin motors. Pentax called this Supersonic Drive Motor lenses (SDM).
CPAP Therapy is a way to live.Pentax K-II cameras has it lens focusing motor in the camera body. However some Pentax lenses have motors in the lens . Why?Roy
