If that is your budget, then perhaps the 1DX should indeed be what you look at. That would take up just under 1/2 your budget, but leaves you quite a bit for some good lenses. With all the improvements other than just ISO on the 1DX (AF, MFA at both ends of a zoom, better auto-ISO, configurable buttons, etc), you would have to decide if the $3000 or so is worth all of that over the 1D4, or if you would rather put that into other equipment.
If I had that budget, I would probably seriously consider:
- 1DX
- 70-200 f2.8 II
- 24-70 f4 IS
- Sigma 120-300 sports
I would try to either leverage sales, canon refurb specials, or lightly used items on the boards to keep all this in budget, but this would be a great overall package. Let's just say, there wouldn't be anything there really to hold you back, other than the size/weight of the Sigma.
I will definitely tell you the 5D3 is a great sports camera, I used it this past entire NBA season, and was able to work with high ISO images pretty well. The 1DX is that on steroids. I also used the 70-200 f2.8 IS MKI lens 99% of the season.
ISO 16000
Here is the first sporting event years ago that I shot with my 1D4 when I first got it. I have learned a few things since, but this was in high school gym lighting.
http://teamspeed.smugmug.com …k#!i=1165646378&k=gLsgG3N

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