This was especially important with the Nikon D3, because the old push-pull 80-200mm f/2.8 zoom lens lacked any stabilization. A rough rule of thumb is that to properly hand-hold a shot without noticeable blur, you want the denominator of the shutter speed to exceed the focal length in millimeters. In other words, faster than 1/50th at 50mm, 1/100th at a hundred, et cetera.
Past about 135-150mm, it's best to err on the side of caution, and I tried to keep my shutter speeds at 1/250th or better with the Nikon, especially because I was hand-holding a 2.73 pound camera with another 2.6 pounds of glass hanging off the front end.
This meant I was shooting at f/2.8 to f/3.5 most of the time, which doesn't give you a lot of depth of field to work with and frankly the old screw-drive autofocus lens struggled to keep up. I missed a lot of shots and when you had a pack of runners, only the center few would be in crisp focus with everyone in front of and behind them all fuzzy.
I only got a couple really decent shots with it.
The other camera I brought was the 2.63 pound Canon EOS 1D Mark IV.
The 1.68 pound* 70-200mm f/4L IS lens on the Canon was stabilized and could run at slightly slower shutter speeds. Further, like all Canon EOS autofocus lenses, it uses a focusing motor built into the lens rather than relying on a motor in the camera body like the old AF Nikkor. In the case of the 70-200/4L, this is Canon's fast and nearly silent "USM" ultrasonic motor.
I got a lot more keepers with the Canon.
I had a pretty enjoyable time and posted a bunch of pics to my Facebook page if you want to see more.
*For those following along at home, that's ten pounds of gear hanging from straps around my neck, which got pretty fatiguing after an hour and a half, let me tell you.
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