One of my two favourite lenses

I absolutely love this lens. This is one of the two sharpest lenses I've ever seen. There is a myth that the pre-IS version of this lens is sharper than the newer IS version. Well, don't buy it. I owned both versions and compared them in great detail and ended up selling the older non-IS unit. It is a bit of a lump (about 2lbs heavier than the non-IS version) but the dual mode IS is excellent and makes hand held shots a breeze. Contrast is excellent with neutral, true colours. Couple it with the 1.4X teleconverter and you have excellent 420mm F:5.6 on a full frame camera or a 672mm F:5.6 lens on and APS-C camera and it is just as sharp with teleconverter (Canon 1.4X) as without. This lens can be had for about 1/3 the price of the 300 F:2.8 and for me the extra stop is just not worth it. This is a nice affordable alternative.