OUTSTANDING lens!!

Typical of 'L' series lenses- this is a great, super sharp lens that is HIGHLY recommended! I have never used a better piece of equipment.

I shoot wildlife- Birds for the most part. I like to shoot handheld, because I get a lot of 'candids' that I would miss if I had to deal with a tripod. The IS is crucial to my work!

First- the only real negative. It is BIG- And HEAVY (at about 3 1/2 pounds), but this is well worth it. The thing is built like a tank. And, compared to 'fixed' telephotos in the same range, it's not all that bad, really. Besides that, you'll be able to cancel your gym membership to help defray the cost.

Ok- On to the good stuff. This lens is SHARP, through it's entire zoom range. I have heard some 'complaints' about it being a bit on the soft side when it is all the way at 400mm, but after using it, I can assure you this id not the case! It is VERY sharp, picking up details that you wouldn't believe from incredible distance.

The zoom on this is a slide zoom. I didn't think that I'd like it at first- But once I got 'used' to it I found it was actually a lot faster and easier to use, especially when I was trying to track flying birds.

At f/4.5-5.6, this isn't exactly the fastest lens out there. But, Used outdoors, I've never had an issue with it. The IS really helps this, too. Besides that, compare the price to what you'd have to pay to gain a few stops in a fixed telephoto, and this is a no-brainer!

Autofocus is quick- Faster than I am. If I miss the shot, it's my fault, not the lens! It also uses the super-quiet Ultrasonic Motor- Which means that you can go to manual focus any time you want just by turning the focus ring- a great advantage sometimes when you're shooting wildlife!

You can also use the canon 2 & 1.4x teleconverters with this, and with the 1.4x still maintain autofocus! (With '1' series cameras, you keep autofocus with both). With a 'cropped frame' digital camera, you get an INCREDIBLE 800mm effective (400mm x 1.4 x 1.6), and STILL have autofocus and IS.