Fantastic lens with no equal.

There are more than a few positive reviews available on this particular item and I must say that I agree with almost all of them. This is a fantastic lens for your Canon camera. The images are nothing short of break taking and will make an amateur shoot like a pro. The ,"L' lenses is what makes Canon the name it is keeping mind mind a lens makes the camera.

Initially I had to drop this unit off at Canon in Orange County with my 30D for them to calibrate the lens to the camera. An otherwise sharp image got even sharper. This was done within warranty and thus no cost to me and something I recommend to everyone as there are always manufacturer spec discrepancies.

The lens comes with a handsome case that offers very little protection so something stronger is recommended to protect this bad boy of a lens as a simple drop on a hard surface from 3' up guarantees damage to the lens while in the case.

I normally stop down my images a full stop for best clarity and this lens is no different. Open wide the images are ok and could be a tad sharper but stepped down it works wonders and it very sharp through the entire field from edge to edge.

The Image Stabilization is superb and works flawless. Quick and accurate under almost every situation though I did find some loss of lock when an object is approaching me such as my dog running towards me from 40 feet away.

The build quality is above par and is typical of Canon L lenses. You get what you pay for here and you know where the money went. This is a solid piece of glass built like a tank. The while paint does scratch easily so be careful there.

Keep in mind that this lens is heavy and requires that one hand is holding the lens and not just the camera. For tripod mount use the lens to mount and not the camera.

Autofocus on fast moving objects is good and is equally good in low light situations. It also has a selector switch on the side for focus ranges for even quicker focusing.

Overall I am very impressed with this lens as it continues a Canon tradition of great lenses.
PROS
Gorgeous Imagery
Fast lens F/2.8
Quality lens.
Fast focus
Low light focus works great
Great bokey
Internal focusing
Image stabilization works great
The WOW factor
Nice dust shield
CONS
Very heavy
Scared to use in case it drops
Some focus lock on moving objects
Not sharp out of the box.
Cannot remove lens cap with dust shield installed as you can with Tamron

Overall a fantastic lens that is highly recommended. If you have the means of course.

Lee Dye
Simi Valley,CA.