I'm debating my upgrade path. I usually go for better quality glass over body upgrades, but I'm not sure on this one.
Do I upgrade my Canon 70-200 non-is 2.8 to the new IS version II of the lens or would it make more sense to keep my older 70-200 2.8 and upgrade my body from the original 5D classic to the new 5D mark III? I'm drooling over the new auto focus system on the 5d mark III but since I shoot sports with a crop camera I'm not sure if I need it. Maybe at 7D and the 70-200 2.8 IS II would be warranted?
I shoot motocross (sports) with my 50D as it has the 1.6 crop factor (free zoom) and a better 9 cross point autofocus vs 1 cross point on the 5d classic. I shoot weddings and general photography/events with the 5d and I consider the 5d my main camera with the 50d being backup unless I shoot the aforementioned motocross or maybe birds.
I love the shallower depth of field that I can achieve when using the full frame 5d vs the crop. It's like getting more expensive lenses with lower maximum aperture when comparing to the crop body. I will always have a full frame. I will probably always have a crop too though for the extra reach.
I also need something for video as well. I'm currently using the T1i for video, but it is up for sale at the time to fund this upgrade. I do some how to videos and make some short films. I do have a canon 1080P video camera for this as well (not as nice as the DSLR's though).
So whats the better upgrade, the 5D to 5D mark III or the 70-200 2.8 non-IS to the 70-200 2.8 IS version II or some other path?
This advise is coming from someone who made the exact same upgrade path. I skipped the MK2 series Btw.
GLASS FIRST! Bodies Second.
If you lack a telephoto lens like the 70-200. Get that first. You can have a mk3 but without the reach, Why bother?
Once you've got all your lens line-up complete, Then invest into whatever body you want. Never deprive yourself of good glass. As for sports, I'm sure you can manage with the bodies you have but the Lenses, You need them more.
I Purchased a MK3 only to replace my dying 5Dc, and For the AF. I never saw the MK2 as enough of an upgrade to justify its purchase.