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For what it's worth, I've owned both the 7d and the 50d. Go with the 7d. The focus sytem is better hands down for what your doing with it (I'm a sports guy, full-time Pro). What position does your son play? Are you shooting from the dugout or through the fence? All these make a difference in lens choice. If you son is an outfielder, you're not going to get much with a 200. I'm not sure of your budget, but a 7d works really well with a 100-400 (in broad daylight, high noon), you'll have all the reach you need. A 70-200 non is (F/4 or 2.8) with a canon 1.4 tc is another logical choice (I don't like a 2x, slows things down too much if you want one PM me I have a low mileage one ). Pick up a 50mm 1.8, everyone from beginner to pro should have one of these in their bag. They are on CL all the time less than $100. On the wide end, start with a kit lens and work from there as your budget allows. My first "L" was a 17-40 on a 10D. You've gotten a lot of good advise here, there are a ton of options. One thing not mentioned, is with the 7D you can shoot some video if you choose.