If you are willing to spend $550 on a ball head, then consider purchasing a gimbal head. The Wimberley heads are the one to get. The 7D + EF 300/4L IS may not be particularly heavy, and a ball head would suffice, but a gimbal head is much better for telephoto lenses and especially birding. You have total control and correct balance at nearly any angle. Gimbal head = you are not messing around.


http://www.tripodhead.com/products/wimberley-main.cfm