As I mentioned in my first post, there are three creative options for each photo shot – exposure, motion, and depth of field. Once a person is comfortable with exposure, motion is the easier one to master of the remaining two. Setting a fast enough shutter speed will stop action, while using a slow enough shutter speed will allow motion blur in the photo. The appearance of motion in the photo is controlled by adjusting the speed of the shutter relative to the focal length and field of view chosen, plus considering the amount of subject motion, or camera motion – or both.
Photographers are often concerned with stopping motion to be sure everything and everyone in the image is tack sharp. A general rule of thumb for stopping both subtle subject motion and camera motion is to use a shutter that is at least 1/ focal length being used. If your camera zoom is at 50 mm focal length, you’ll need a shutter speed of at least 1/50 sec. to get a sharp photo. For a faster subject motion moving sideways across the view, choose a shutter at least 1 / ‘focal length plus 1 stop’ (1/50 plus one stop faster = 1/100). The faster the motion is and the more sideways the motion is to the angle being shot, the faster the shutter speed needed relative to focal length. Some situations may require 1/ ‘focal length plus 2 stops’ (50 mm – 1/50 plus 2 stops = 1/200) or even 1/ ‘focal length plus 3 stops’ (1/50 plus 3 stops = 1/400).
These suggestions work well for full frame sensor cameras. My next post will cover crop factors for cameras with smaller sensors as these may change the shutter speed you need.
If you would like to learn more about photography from Carl Heilman II check out his workshops.