whats the differnce between non usm and usm?

[YYZPICS]

Canon EF 75-300mm f/4-5.6 III vs Canon EF 75-300mm f/4-5.6 III USM
is there a big differnce between the two?, all i know is that the non usm is $30 cheaper.

[Airbus_A320]

The USM is a better focusing motor. I would get the USM version.

[E-Diddy!]

not having the USM I'd say you should definetly get the USM

[B1RJ85/100]

I have the USM one and I am very happy with it, I have never tried the non USM version but I really think it's worth to put extra money and get the USM. I don't have regrets about this purchase.

[Genessee]

Canon has a page on the motors. It's not much, but gives a decent short description.

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

[medic1]

For $30 I would definetly get the USM

[Andrew Wettlaufer]

For spotting USM makes sense!

[Leftseat86]

If it doesnt say USM then it sucks.


^^best explanation ever.

[YYZPICS]

thanks all for the help, ill be purchasing the usm version tonight