"Skip M" wrote in message
news:n2tNe.1681$sw6.1461@fed1read05...
"Tony Polson" wrote in message
...
"Skip M" wrote:

Well, they must have left something out, since one version of Sigma's
HSM
lacks full time manual, and both versions sound like coffee grinders
compared to Canon's versions.

That's Sigma for you. I recall dismantling my Sigma 24mm f/2.8 for
Nikon AF which was noisy, only to find large quantities of brass swarf
and powder where the AF mechanism used to be. It ground itself into
oblivion.

USM was probably too specialized for Sigma to
say they hit on it by independent research.

Agreed.

The mount may not have been
strictly patentable, since it is a concept, broadly speaking...

The mount is not the real issue, it is the electronic interface.


True, and I wonder if you can patent the placement of wires, which, after
all, is what the interface boils down to.

--
Skip Middleton
http://www.shadowcatcherimagery.com



You made the mistake in posting "... True, and I wonder if you can patent
the placement of wires, which, after all, is what the interface boils down
to. ..."

In the modern digital world ... that is so far from a true statement as to
be almost comical. The lens-body interface in a modern Canon camera is
probably a complex digital serial bit stream, and has very little to do
with "the placement of wires."