My expectation (hope) is that on long lenses, USM will be significantly faster. On short lenses I don't need or expect much difference.
I really don't see the point of USM on short lenses (because they focus fast enough), and I don't see the point on long lenses if it doesn't yield a speed improvement. As somebody pointed out (Shel?), it would be very nice to have better low light performance. John On Thu, 02 Nov 2006 18:09:50 -0000, John Francis <[EMAIL PROTECTED]> wrote: > On Thu, Nov 02, 2006 at 11:03:09AM -0500, Mark Roberts wrote: >> Shel Belinkoff wrote: >> >> >> From: Joseph Tainter >> > >> >> He was given the opportunity to claim that SSM would be faster, and >> he >> >> didn't bite. So the only advantage is that it will be quieter. >> > >> >Joe, every silver lining has its cloud, eh ;-)) >> >> You know, I've been reading for years, from people I trust on this list >> and elsewhere, that the primary advantage of USM/HSM/SSM/whatever is >> that it's quiet rather than faster. No one should be surprised at this >> point. > > It's faster on the cheaper bodies, which have under-performing motors > in the camera. With a semi-pro or better body, though, the actual > operation of the focus process is around as fast with most lenses, > although it has been my impression that the largest, heaviest lenses > still make things difficult for the body. I'm looking forward to > trying the K10D with my FA* zooms. > > I'm also expecting to find, from all I hear about the K100D, that the > speed of decision-making in the auto-focus logic has been improved. > > I've used a Canon 20D with the 17-85 USM lens under indoor lighting, > and there's no doubt in my mind that it is faster in operation than > my *ist-D with my 28-105. I've also had a chance to check out the > high-end Canon bodies with long glass, and a Nikon with the 80-400, > and definitely found those to be faster overall, though not by a lot. > > I expect the K10D, with either the FA* 80-200 or DA* 50-135, to be > faster in operation than my PZ-1p or *ist-D. My personal belief is > that the DA* 50-135 will be slightly faster than the FA* 80-200, > but I'm prepared to be proved wrong. > > -- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/ -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
