How does USM help?

[cbay]

Hello

I have got USM on both of my lenses and i paid the extra to have it but im not entierly sure how it helps. Please could someone explain further.

 

[Meysha]

Does USM mean Ultra silent/sonic movement... or something like that. So basically... it's quiet.

I think it's also faster than the normal canon focussing lenses. I'm now off to find you a proper link that actually knows what it's talking about....

 

[Meysha]

From the Canon website: Glossary:

http://opd.usa.canon.com/html/eflenses/lens101/glossary/index_s.html#ultrasonic

Basically it's fast, more expensive and better.

 

[LittleMan]

Features of the ring-type USM include its ability to easily achieve the low-speed, high-torque characteristics needed to realize direct drive. Large holding torque means the disc brake automatically holds the lens in place when the motor is stopped.

That will give you a very crisp image when other lenses without USM won't.

 

[Meysha]

Large holding torque means the disc brake automatically holds the lens in place when the motor is stopped.

Without this advanced feature of the brakes actually stopping stuff, the huuuge torque power would literally rip the lens off your camera and go rolling down the street.

Ahhh I love the people who write these blurbs.

 

[LittleMan]

Without this advanced feature of the brakes actually stopping stuff, the huuuge torque power would literally rip the lens off your camera and go rolling down the street.

Ahhh I love the people who write these blurbs.

:lmao:

 

[DocFrankenstein]

USM
1) Focuses faster, quieter. No buzzy noises like my 50/1.8
2) It focuses accurately, because it can change speeds. Where non USM lenses focusing accuracy is limited by the minimal shift of the motor rotor, IE 1/3 or 1/2 a turn... USM lenses are not.

This results is faster and accurate focus and a USM lens hunts much less than a non usm lens does, giving you opportunity to shoot easier.