My first post. Hope I can add some info. Have 7D just bought 5D markIII, trying to ignore the suggestions of soft focus. Frighten animals each year in Kruger park with my 70-300mm lens which is perfect for use from a vehicle, with the 7D, if using tripod for longer range shots even a 500mm length might still not be long enough, and it is too heavy for hand holding.So now it's down to the 5D with shorter range (no crop factor). I've tried both camera's and yes there is a closer picture with the 7D, but with the extra 5 Megapixels of the 5D a very small crop gets you to the same size shot, without loss of quality on one hand, but you gain very fast auto focus, several stops of usable ISO re loss of light in afternoons/evenings. The real trick however with the 5D mark III, is the extra speed that you really need for hand held pix that you get from the extra ISO at any time, like 1/000/ or 1/1500 sec.gets you the sharp pix you're praying for. One more suggestion from Art Wolfe don't take portraits all the time, let a little of the background scenery into your shots to help tell the "story" (Thanks Art!!) A 70 - 300mm is plenty in that situation. No disadvantage I can see with the 5D versus the 7D,- Beemar.