usm or non-usm lens

[helen_manton]

A quick question what is the difference between anUSM lens and a non-

USM lenes.

 

i understand that they are quieter and quicker to focus so is it

better (or any point) in getting a USM lens for when shooting

wildlife?

[grahams]

Helen - USM stands for "Ultra Sonic Motor" and describes the type of motor that is used to actuate the auto-focus mechanism of a Canon AF lens. There are two main types of USM motor, the ring motor which is built around the circumference of the lens barrel and which is used on the "L" lenses and some of the higher quality non-L lenses (such as the 28-105 3.5/4.5 USM) and the micro-USM motor which is a small capsule USM motor incorporated into the rear of the lens. The ring motor is quieter, faster and more reliable, and more costly.

 

Non-USM lenses focus using a simple DC electric motor that is noiser, slower, and much cheaper to manufacture.

 

For wildlife shooting, a ring USM would be the best, because it is virtually silent, although some people say that some animals can hear the frequency of the motor. On the other hand, I used a 75-300 4.5/5.6 USM III, which has the micro-motor and is quite noisy, for wildlife (deer) without problems. It all depends on the ambient conditions, wind noise etc. That said, if you can afford USM ring motor lenses, there is no question...

[Greg M]

To effectively shoot wildlife you need longer lenses. Other than the 75-300 lens mentioned above and the really cheap 75-300 non USM, all of Canon's current 300mm or longer lenses use the ring USM technology. You do not have the option of a non-USM lens unless you choose one of those two lenses.

 

My cat sure hears my USM lens focus. I can go around a corner out of his view and silently focus on something and I hear him meow in anger. He hates them. They maybe silent to us, but not all creatures hear on our level.

[yakim_peled1]

<p> <a href="http://photonotes.org/articles/beginner-faq/lenses.html#lensmotor">What is the difference between the various kinds of lens motors (AFD, MM, USM)?</a> </p>

<p> I am a big fan of USM. I have 3 lenses which have it (85/1.8, 200/2.8, 300/4 IS) and two which doesn't (24/2.8, 35/2). I really wish I had USM on my non-USM primes but the 24/1.4 L USM and 35/1.4 L USM are <b>way</b> too expensive to justify the added cost. For wildlife you need telephoto and fast AF is important. I therefore advise you to get a USM lens, provided you are not compromising on optical quality.</p>

 

 

<p>Happy shooting,<br>

Yakim.</p>