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Difference between a non USM and USM lens??

PostPosted: Thu Nov 15, 2007 11:17 am
by mrjake2002
Hello. I'm looking to buy myself a DSLR camera (probably a Canon EOS 400D Digital Rebel XTi). It comes with the 18-55mm lens kit and you can get a EF90-300mm non USM lens fairly cheaply with it. I was wondering, what is the difference between a non USM lens and a USM one? I've noticed most people have USM lenses but im not sure what it means.  :-[ Help appriciated.  :)

Re: Difference between a non USM and USM lens??

PostPosted: Thu Nov 15, 2007 11:23 am
by Hagar
USM means Ultrasonic Motor. http://photonotes.org/cgi-bin/entry.pl?id=USM

[i]"USM.

(Canon) Ultrasonic motor. Canon

Re: Difference between a non USM and USM lens??

PostPosted: Thu Nov 15, 2007 1:02 pm
by Mictheslik
The focusing is much quicker, but personally, I don't notce a difference in noise....

I would reccommend USM, especially for aircraft/fast moving abject shots ;)

.mic

Re: Difference between a non USM and USM lens??

PostPosted: Thu Nov 15, 2007 4:54 pm
by mrjake2002
Cheers. Looks like I'll just have to be patient.  ;) Might I ask how much you paid for your kit mic?

Re: Difference between a non USM and USM lens??

PostPosted: Thu Nov 15, 2007 5:14 pm
by Mictheslik
Cheers. Looks like I'll just have to be patient.  ;) Might I ask how much you paid for your kit mic?


Camera + 18-55 was