Re: New 100-300/4 and 28-70/2.8 lenses from Sigma!

[Ryan K. Brooks]

Len Paris wrote:

It seems that apart from marketing blah blah, the only advantage of USM is its quietness...


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Best Regards
Sylwek

I think, maybe, there could be some mechanical efficiency gained by
putting the focusing motor in the lens itself rather than in the camera
body. It could lead to slightly faster, as well as quieter, focusing. I
would need to buy a few more USM/HSM lenses to be able to say for sure,
though.

Well, it (USM) certainly seems to allow you to have AF in lenses that we don't.

R