USM lenses

[WAL]

I have been looking at purchasing a new 70-200mm lens for my Rebel. There seems to be a bit of information overload on the internet and so, in very simple terms, can someone tell me the difference between the USM lenses and "standard" ones. Is it worth paying the extra money for the USMs?

Regards

WAL

[tim]

USM lense focus more quickly than non-usm lenses, and they're quieter.

[Jesper]

USM = Ultra Sonic Motor

There are different types of USM in Canon lenses. The good ones have a ring-type USM motor, and there's also the micro motor version. With ring-type USM lenses, you have FTM - Full Time Manual focussing, which means you can manually focus the lens without having to flip the switch on the lens to MF.

Here is Canon's description of USM: http://www.usa.canon.com/html/eflenses/technology/ultrasonic.html

[cmM]

all the 70-200 are usm aren't they?
But yea, I'd say its worth the money.

[IanBMW]

Oh man USM is AWESOME. Having to switch to manual can be a pain sometimes. And talk about silky smooth, you can honestly feel the difference. Also they dont pop like a standard lens does when it focas's. Hard to explain, but pick one up and you'll know.

[CyberDyneSystems]

Regarding the difference,..

It is so important to me that there are only two types of lens I will purchase.

Canon USM lenses,. and Sigma HSM lenses (Sigma's version of USM is "HyperSonic Motor)

Anything else just seems much to slow to focus.

[ScottE]

For me the main virtue of Canon USM and Sigma HSM lenses is that they have full time manual override. That way I can assign autofocus to the * button and touch up focus manually any time I want.

Watch some of the older USM and HSM lenses because they do not have this feature.

[willg]

they focus sooo much faster...unfortunately i do not have any usm lenses, but i love using my friends usm zoom lens because its silent compared to my tamron zoom

[Wavy C]

The Tamron 28-75mm might be a exception. Although it doesn't have usm, I'm considering buying it because a it gets great reviews. The lack of full-time manual override bothers me a little, but it seems the focusing is fast enough.

[CyberDyneSystems]

The Sigma alternative to the Tamron,.the 24-60mm f/2.8 EX HSM is woth a look too if the fast focus is a concern.

[RichardtheSane]

The Tamron 28-75mm might be a exception. Although it doesn't have usm, I'm considering buying it because a it gets great reviews. The lack of full-time manual override bothers me a little, but it seems the focusing is fast enough.
I sold my Tamron 28-75. One of the two things that I found was the focusing was simply not fast enough for me.