What would be a good addition to add to my collection? I use a 5D MkII, 24-70, and 100mm macro. I've always wanted to get a zoom lens for the camera, but I can't decide which one to go with. I'd rent glass but would prefer to put that money into the actual lens. Three I were looking at (to keep the cost realistic) are the 100-400 f/4.5L, 300mm f/4L, and 400mm f/5.6L (no IS). I would assume the primes would have greater sharpness over the zoom but reviews on all three lenses are great. People doing the 300 or the 400 primes recommend a 1.4x teleconverter. Light shouldn't be a big deal I don't think. The 5D2 can easily bump ISO with no problem. What are your opinions? Possibly any example shots? Or even another recommendation on a lens with a price near the above 3 that I may have missed that could be better? Thanks!