I got a new lens. It is the Canon EF 100-400 f4.5 L series IS zoom. I wanted to know if it was better than my 75-300 IS and went out to take some photos. The left is the 100-400 and the right is th 75-300. Both sides are the same number of pixels, the size difference being the focal length. First crack out of the box the 100-400 looks quite a bit better.