Extremely useful lens

I have had this lens for about 18 months now, and I have never regretted buying it. This was my first lens when I switched from Pentax to Canon, and I immediately fell in love with Canon's USM technology -- it focuses so fast! (That was the reason I switched.) A photographer friend told me to buy it because the image stabilizer was very useful. I didn't quite realize the gravity of it at the time but he was so right -- you can reliably take 1/20 sec photos at 135mm -- I have done it at weddings with consistently perfect results. This technology lets you take photos that otherwise would be impossible. I use my tripod about a quarter as often as I did before I bought this lens.

The optical quality is good -- not as sharp as a prime lens or 'L' series, but I have some amazingly sharp photos from it. I have read reviews on the net saying that this is the sharpest non-'L' series lens that Canon makes, and some of my photos would tend to support that.

The zoom range of the lens is very useful, especially for portraits. This is an excellent lens for weddings, etc. I would like it if it went down to 24mm but you can't have everything! With the image stabilizer, this lens really is in a class of its own.