Japakomom wrote:
I initially thought of the 7D II,
but how will that perform with poor high school stadium lighting? High school stadium lighting in North Carolina is not nearly as good as it is in Texas
That is why I have been sticking with the 6D.
Superbly!
I shot an event recently with my pair of 7DII at ISO 8000 and 16000.
It also was under sodium vapor lighting, which behave the same way as fluorescent, causing a lot of cameras to incorrectly expose and give problems with color shifts. The 7DII has Flicker Free mode, where the camera times the shutter release to the peak of they lighting cycle (which is a 1/120 second occurrence with this type lighting in the US, so you don't notice any shutter delay). The AF system worked very well in those low light situations, too.
Frankly, 6D is about the last Canon I'd want to use to shoot sporting events. It's a great camera for scenics and low light, fine for portraits or macro... but the AF system and frame rate are nowhere near what's needed for action shooting. Only one of the 6D's 11 AF points is cross type that works best for AI Servo and tracking movement. The other 10 points are pretty much worthless for those purposes. In comparison, 7DII has 65 AF points, all cross type. Any one of them are usable, and the camera is also pretty brilliantly capable of working with groups of AF points (I use Small Zone a lot... there are also Large Zone, 4-Point Expansion, 8-Point Expansion and All Point multi-point patterns available. That's in addition to Single Point and Spot Focus/Precision Single Point). The original 7D's 19-point AF was very fast acquiring and excellent tracking movement, too... But I mostly used it with Single Point, since the points are farther apart than in the 7DII.
The only Canon with a better AF system for sports than 7D-series are the 1D-series. But I also would much rather shoot sports with a crop sensor camera, which allows use of smaller and lighter lenses, leaving me more mobile (and less tired at the end of an 8 hour shoot).
70D, T6i and T6s all use an AF system largely inherited from the original 7D and the new 80D has it's own unique 45-point AF system. Any of these would be pretty good for sports, too... though a little less so than 7D-series because it's AF system is "1D-like", i.e. run by a separate chip. Most other Canon use the same processor for AF that's also handling images.
Among the FF cameras, the 5DIII (and probably future 5DIV) and 1DX-series all have advanced AF that's very capable of handling sports/action. They still wouldn't be my choice, though, because lenses for them are necessarily a lot larger and heavier. For example, to frame a subject the same way I do with 7DII and a very hand-holdable 300/4, with a FF camera I'd have to use a much bigger, heavier 500/4 (and a tripod to sit it on).
For sports it's important to pair up the cameras with fast-focusing lenses.... Canon USM are among the best (a few USM lenses aren't built for speed, but most are). I use two Canon 70-200 (both f4 and f2.8 versions), 300mm (both f4 and f2.8) and 100-400 a lot. I also sometimes use 24-70/2.8, 28-135 IS USM, 500mm, 10-22mm and a few others. I don't use, but imagine Tamron USD and Sigma HSM lenses have similar AF performance to Canon USM.
So, unless you have other uses that require the FF camera, for the type of shooting you're doing I'd strongly recommend switching to an APS-C camera: 7DII, 80D are the latest and greatest, original 7D or 70D also can serve very well. 6D is just about the least sports-oriented camera in the Canon line-up. (Note: the 7D and 70D don't have the "Flicker Free" mode mentioned above... the 7DII and 80D both do.)
Any of these APS-C have image quality that's more than enough for typical sports shoot purposes. The least of them (original 7D at 18MP), I've made as large as 16x24" prints that were excellent. 7DII I use now are both a little higher resolution (20MP). 80D is 24MP.
As a bonus, one of these APS-C models will cost considerably less than a FF model, whether a 5DIII or a 5DIV (when the latter is announced, possibly later this month, I suspect body only will cost around $3200 or more).
And a lower cost crop-sensor camera should leave some money in your budget to upgrade your lens, too.
I haven't used the 70-200 you mention.... would recommend the Canon anyway. The EF 70-200/2.8 IS USM Mark II is considered by many people to be the best 70-200 made by anyone... But it's fairly expensive at close to $2000. For a lot less money, if you would consider used the earlier version of that lens is quite good too. There also is a less expensive non-IS version (though personally I want my telephotos to have IS). Or, there are two f4 versions (one with IS, the other without) that are smaller, lighter and less pricey.
If you want a shorter focal length to complement any of those, the Canon 28-135mm is a good choice that can be found new or used relatively inexpensively, and is fully up to sports/actions shooting. A 24-70/2.8 is better built and might be nice in lower light conditions, but will be bigger, heavier and a lot more expensive. The Canon 24-70/4L IS USM might be worth a look.
If you need longer focal length, the Canon 300/4 IS USM works very well, too. The 70-200/2.8 IS II works pretty darned well with a 1.4X teleconverter (I'd probably look for a Canon "Mark II" or a Kenko DGX. The Canon Mark III TCs are actually designed to slow AF a little.... about 25%... for accuracy, over speed.)
Rather than dropping $3200+ on a FF camera... put $1000 to $1500 toward a camera and $1000 to $1500 toward a new lens. I think you'll be glad you did, since the camera will be much better for sports/action shooting than what you've been using!