ANY 12lb lens that is being shot handheld would benefit from IS. Under the old inverse of focal length rule, 1/600th would be the slowest shutter you should expect sharp pictures with the lens, with IS you could conceivably shoot as slow as 1/125th with similar sharpness. Personally, I doubt there is any shutter speed I could handhold with that much weight and get good results, but that's just me.
and Ultrasonic = USM. Another EF lens rule: if it's white, it's USM. Tom P. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Reese > Sent: Sunday, December 04, 2005 12:50 PM > To: [email protected] > Subject: Re: EOS EF compared to EF USM and IS compared to non IS > > 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 ***********************************************************
