Tuesday, August 5, 2008

Taking Dynamic Action Shots

There are quite a few different ways to take an action shot. The most straight-forward approach is simply to set your shutter speed fast enough to freeze the action and shoot. Although this approach can work quite well, as you'll see, making a truly dynamic and interesting shot requires a bit more work than just adjusting your shutter speed and firing off a bunch of frames.

This first image was shot using Shutter Priority mode and Matrix metering. This being a high contrast scene with parts of the image in shadows and other parts in direct sunlight the camera has problems trying to decide what to expose for. As you can see the sunny part of the sky is blown out and the subject is quite dark and doesn't really stand out from the background. The shutter speed of 1/640 is plenty fast to freeze the action, but due to the exposure problems the image just doesn't stand out.

To help the subject stand out from the background I switched to center-weighted metering. This mode bases 75% of the exposure from the center of the frame and 25% from the rest of the frame. As you can see this exposure is brighter than the last one. On one hand, the subject is properly exposed and popping out from the background more, but there are seriously blown out highlights in the sky which are very distracting and draw attention away from the subject.

For this next shot I added some flash to help the subject "pop" and adjusted the exposure to rein in some of the blown-out highlights. I used an SB-800 off camera to the left controlled by the D700's built-in flash. The camera is still set to spot meter and shutter priority and the flash is set to TTL with the built-in flash adding nothing to the exposure. In this image the subject is well lit and stands out from the background, but there are still some uncontrolled highlights on the right side of the frame. It's an OK shot, but the blown highlights are distracting and it's just not a dynamic image.

To make this shot work I switched the camera to Manual exposure mode and Spot metering. I pointed the camera at the brightest part of the sky and took an exposure reading. This gives you an exposure that allows you to avoid blown-out highlights and get highly saturated colors. This actually, in effect, under-exposes your image. Next, I set the SB-800 to TTL with +2EV. This allows the subject to be slightly over-exposed causing it to stand out.

The combination of the under-exposed background and the over-exposed subject gives you a dynamic image with punchy colors and lots of contrast. In addition, I panned along with the subject to add some motion blur to the background to suggest movement while the short duration of the flash freezes the actual motion of the subject.


Patrick said...

You've got a cool blog going! Keep it up.

J. Dennis Thomas said...

Thanks Patrick!

Encouragement is always appreciated!

Dez said...

... it's true - an unknown blog. great info here. you should keep doing this more often. BTW, I recently saw your new D300 book with that shot I took of you at the races. Thanks for the creds.

Anonymous said...

Hey dude,
Thanks for the lesson :)
I was just wondering how you did the focus?
Camera setting for it, pre focus? anything like that

J. Dennis Thomas said...

Ultra-wide lenses have a deep depth of field so focusing isn't too hard.

The shots with the 12mm I used Continuous AF set to 51 point 3D focus tracking. I panned with the skater during his run up.

The fisheye shots were manual focus. I focused on the lip of the ramp and used a small aperture to make sure I had a deep enough focus.