----- Original Message ----- From: "Inner Focus" Subject: Sigma HSM lenses for Pentax KAF mount
OK, I also have a question: what's the advantage of ultrasonic motors? I'm interested in AF speed, since I've had a lot of trouble with my camera and it's kit lens (annoying AF hunting or even impossible AF in not-so-low :( light). USM has the potential to be faster, but is not necessarily going to fix your problem. Kit zooms are pretty dim, and often rather low contrast lenses, so the AF doesn't get as much light to work with, and what it does get isn't as good quality, as AF is contrast sensitive. AF performance with an f5.6 lens is enormously compromised in surprisingly bright light. Try a better quality lens. Even an AF50/1.7, which isn't overly costly, will give an indication of what the kit zoom is costing you in performance. I think you'll find that if you are really interested in fast AF, you should be looking at the top end Canon or Nikons and their fast glass. Expensive, but really high performance, and they don't take Pentax lenses, which is a fatal flaw. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
