Shoot Happens

Thanks for the compliment. I agree that opening the aperture up is best for both bokeh and faster shutter speed but I found when shooting martial arts, the competitors can move very rapidly both forward and back as well as side to side. I have shot wide open at 2.8 but find the DOF to be so shallow that the focusing cannot keep up with the quick movements of the competitors. In addition, with arms and legs stretched out it is highly likely part of the competitor is in focus and the other is not, taking a gamble the part you want in focus, is in focus. If the right parts are in focus it was often more luck than skill. Thus shooting at f4 and f5.6 I found consistently gave me the sweet spot for keeping the subject in focus while keeping the aperture as open as I dared.

Shoot Happens

Thanks for the compliment. I agree that opening the aperture up is best for both bokeh and faster shutter speed but I found when shooting martial arts, the competitors can move very rapidly both forward and back as well as side to side. I have shot wide open at 2.8 but found the DOF to be so shallow that the focusing cannot keep up with the quick movements of the competitors. In addition, with arms and legs stretched out it is highly likely part of the competitor is in focus and the other is not, taking a gamble the part you want in focus, is in focus. If the right parts are in focus at f2.8, it was often more luck than skill. Thus shooting at f4 and f5.6 I found consistently gave me the sweet spot for keeping the subject in focus while keeping the aperture as open as I dared.

Robeng Loc: California

I would say not knowing the lighting conditions, but having been to numerous martial arts tournaments, I would take the D3 over the D5200 because of better high ISO. You figure karate tournaments have lots of fast movements so you're going to have to use fast shutter. I don't know how far or close you're going to be from the karate kid so I would take both lenses.

cjc2 Loc: Hellertown PA

The D3 is designed specifically for sports work. Opening up your lens will allow a faster shutter speed as well as focus attention on what's important. As with any sport, part of the issue is getting the right moment, and that is a result of understanding what's happening and what's going to happen in the sport and experience. Experience can't be taught, it can only come from shooting, shooting again and shooting some more. Use you camera to assist you and go get some more experience. In some cases, experience only comes after years of attempts, and then, suddenly, it all clicks! Chances are that with more experience, shooting wide open, at a faster shutter speed, and ISO, if necessary, will improve your work by letting the camera "work its mojo"! Best of luck.