I am thinking of buying a Canon EOS 300. I know very little when it comes to specifications. Can any one explain to me what USM stands for and what it is and does.

-- Ray Ayers (ray@ayers4.fsnet.co.uk), April 05, 2002

Answers

USM stands for Ultra-Sonic Motor drive for focusing. most (almost all) cheap lenses have Micro-Motor (MM) drive for focusing. a USM drive is silent and (may be) slightly faster than MM drive. if you take a little effort to go through various posting in this forum under the category EOS Lenses you will find much more useful information about lenses. everyone will suggest you NOT to buy the kit with 28-80mm or 28-90mm lens. since you have not yet bought the camera you can think about buying only the body and lens separately, probably 28-105mm or 28-135 IS lens.

-- sajeev (chack74@yahoo.co.in), April 05, 2002.

http:// www.photo.net/canon/lens-motors

-- NK Guy (tela@tela.bc.ca), April 05, 2002.

http://www.usa.canon.com/eflenses/technology/ultrasonic.html

http://www.canon.com/camera-museum/tech/room/f_index.html

-- Peter Phan (pphan01@hotmail.com), April 05, 2002.

http://www.usa.canon.com/eflenses/technology/ultrasonic.html

http://www.canon.com/camera- museum/tech/room/f_index.html

-- Peter Phan (pphan01@hotmail.com), April 05, 2002.