When people tell me that they are unhappy with their action photos, one of the first things that I check is are the photos in focus, or are they blurry? If they are not sharp, most of the time this will be due to shooting with too slow a shutter speed.
One of the beauties of todays new cameras is that you can set the camera on a “program” mode, and the camera will choose your settings for you. However this is also a downfall. The camera does not know that you are trying to capture action, and will likely select an average shutter speed and aperture for the light conditions.
Shutter speed is the amount of time the shutter is open, and in combination with the aperture determines the amount of light that reaches the sensor or film. Shutter speed determines how motion is captured, and a short shutter speed can freeze the action, while a long shutter speed can blur motion.
When I photograph horses in motion, I use a setting that is called “shutter priority” (called Tv on many cameras) which allows me to slect the shutter speed I want, and the camera will select the aperture to go along with that shutter speed. My reason for doing this is that I like to freeze the action when a horse is in motion.
When a horse is walking or trotting, you will need a shutter speed of at least 1/500 to freeze the motion. When a horse is galloping, use 1/1000 or higher. Try different shutter speeds in different situations, and see what you like best. There is no right answer, but changing your shutter speed will improve your action photos of horses.