On Oct 5, 2005, at 7:25 AM, Adam Maas wrote:
The most important factor is how efficienty the overall system works.
Lens driven AF is more efficient than body driven AF.
I very much doubt that this holds as a general claim.
This is a general truth in the mechanical engineering of servo
systems. Reducing the number of bits between a motor and the thing
being driven always reduces power losses and increases control.
Motors can be made smaller and lighter, lower power, etc.
Canon's lenses are state of the art mechanically. The ring motor USM
mounts are excellent. Although they tend to make the lenses a bit
more bulky, when it comes to operation I cannot fault them in any way.
Godfrey
