thank you everyone for the replies. > USM comes in multiple flavors - hence it behooves to > do one's research well.
This is obviously a lot more complicated than I thought. To be more specific with my question: I'm trying to figure out the differences between: the older non IS 600/4 series II lens (it does say ultrasonic on the lens barrel but it is not designated USM) the newer IS USM 600/4. are there focusing differences between the two lenses? Is the IS version demonstrably sharper off a tripod? thanks * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
