"Motion Blur Experiment on D7000" Tue 25-Dec-12 04:33 AM by Danbie
I while ago there was a post about what settings to use for a D7000 to shoot an indoor basketball game. The author indicated that his photos tended to be a little soft and he shared a few. Truth was that with a little sharpening the photos looked fine for web use and they would probably even make reasonable quality 8x10s. The photographer was using a shutter speed of 1/500s and there was some discussion about whether this was fast enough. My experience is that when shooting basketball from the baseline I try to use a minimum of 1/800s and I push up to 1/1000s when the lighting is reasonable. I find that my photos are sharper when I do this and because I shoot to make and sell large prints (up to 16x24) I want to keep most of the pixels and I want them to be very sharp. Some folks spoke up and said that my technique must be bad because they get good shots at 1/500s. They posted a few shots as evidence but again … I agree that 1/500s is fine for posting a photo on the web but you are losing resolution due to subject motion blur. So I decided to do an experiment. I hung a 6 inch nail with thread to make a pendulum. The total length of the pendulum (to the tip of the nail) is 31 inches. I lift the nail 5 inches above its lowest point and let it swing. Using some math (including second order harmonic corrections) I calculate that the maximum speed at the tip of the nail is about 3.5 mph. I postulate that this speed is a reasonable one to test as the residual motion of the basketball player (even with panning) could easily reach this speed (consider an arm moving or head twisting quickly). Next I set up by D7000 with a nikon f/1.4 50mm lens on a tripod 15 feet away from the nail. I set the focus to manual, quality to raw, f-stop to 2.8. I then vary the shutter speed and iso so that the exposure stays essentially the same (1/250s at iso 100: 1/500s at iso 200, 1/800s at iso 340, 1/1000s at iso 400, and finally 1/2000s at iso 800). The first photo shows the set-up. The rest of the photos are cropped 1:1. Each raw photo was processed in Lightroom 4.2 using the default settings I think the results are clear. If you want the best resolution that a D7000 can provide (given the conditions I used) then a shutter speed of 1/2000sec is best and each shutter speed below that gives a little less sharpness due to subject motion blur. 1/1000sec is not too bad. 1/800 is worse and 1/500 is worse yet. 1/250sec is (of course) terrible. I know you can get great shots at a basketball game with 1/500s from the baseline (especially when they don’t move laterally very quickly). But if your subject has arms moving fast or head turning quickly or there is some other motion that you just can’t stop with good panning, then your shot will not be as sharp as it could be. It might still be fine for an 8x10. But the sharpness of an 16x24 will be adversely affected. I also realize that resolution is not everything about quality. Too much noise can also be detrimental. And sometimes I do shoot at 1/500s because the light is so bad. So it is a balancing act. But the point I want to make is that a setting of 1/500s can easily result in lost resolution due to subject motion blur. It is not simply bad technique.