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In order to achieve critical autofocus, the elements within a camera lens have to move quickly, quietly, and with exacting precision. To accomplish this, Canon developed the world's first lens-based Ultrasonic Motor (USM). Based on a totally new technology, the motor spins by ultrasonic oscillation energy. In effect, instead of a large, noisy drive-train system, electronic vibrations created by a piezoelectric ceramic element power the mechanical action of the lens. In a very broad comparison, it's like the difference between a mechanical watch with gears and springs and quartz-timed watch movement. Therefore, torque is constant and start and stop functions virtually instantaneous.
By making the autofocus operation almost inaudible and by accelerating the autofocus speed, this type of motor greatly expands the shooting possibilities for Canon photographers. There is virtually no whining noise as the lens focuses to distract the subject or draw attention to the photographer. Most important for the photographer in the field, the motor draws minimal power so the camera batteries last longer.
Customers most agreed on the following attributes:
[0 of 3 customers found this review helpful]
from Lockport,IL on 2/3/2009
Comments about Canon Canon 24-70 f/2.8L USM Lens:
I have waited a long time to get a professional
lens and this is exactly what I wanted!
[1 of 4 customers found this review helpful]
from Butler, PA on 2/3/2009
Comments about Canon Canon 24-70 f/2.8L USM Lens:
I purchased two lenses and one flash from your company. I have not been able to use any of these items since I am still waiting for the camera body that I ordered from your company [...]I am very excited about using my new camera and lenses, so I am a bit impatient for my camera body to arrive!Thanks!Laura Vernon
from Rocklin, CA on 12/10/2008
Comments about Canon Canon 24-70 f/2.8L USM Lens:
When I have to travel light or don't feel like carrying around too much gear with me, I take this and the 70-200 f/2.8 L with me, they compliment each other very well. This lens is fast which is a must for action. All around its a great lens to have in any situation
[2 of 3 customers found this review helpful]
from WA on 11/8/2007
Comments about Canon Canon 24-70 f/2.8L USM Lens:
I love this lens! It is great!
[3 of 4 customers found this review helpful]
from Portland on 10/4/2007
Comments about Canon Canon 24-70 f/2.8L USM Lens:
Get this beauty and do the magic with it !
[4 of 4 customers found this review helpful]
from Colorado Springs, CO on 2/18/2007
Comments about Canon Canon 24-70 f/2.8L USM Lens:
I love this lens! The color, the bokeh, the sharpness, everything about it is amazing. It is the lens I use nearly all of the time. The range is great on my 30D, perfect for portraits. It is quiet, and solidly built. I take a lot of landscapes and hike quite a bit with this lens. It is quite heavy, but I have gotten very used to the weight!
[8 of 8 customers found this review helpful]
from Jacksonville, FL on 2/17/2007
Comments about Canon Canon 24-70 f/2.8L USM Lens:
OK, so I haven't used every Canon lens in the arsenal. Still, I've used a lot of them and this lens, in an extremly useful range returns great clarity, perfect color and the 2.8 straight through gives spectaculr results in low light ameks for some wonderful blurs when desired. This lens is on my camera 80% of the time.