In short, shutter speed is the time the shutter on your camera is open at any given moment. Many elements come into play when determining what shutter speed to use for a photograph. Do you want smooth water, streaking clouds, are you shooting action, etc? One thing to remember is the average person with real steady hands can hand hold a camera with a shutter speed no slower than 1/20 sec. Any slower and you cannot hold the camera steady and the photo will not be in focus.
Using a fast shutter speed allows you to freeze the action. This next photo was taken at 1/640 of a second. If the shutter was around 1/100 of a second it would show too much movement in the wave.
Using a slow shutter speed has many advantages. Photographing streams and waterfalls with a slow shutter will add some motion to the water. In this photo you can see how the water appears to be moving and lead your eye from the bottom right corner to the upper left corner. The shutter speed was 0.8 sec.
If a fast shutter speed was used, the water would not have motion and your eye wouldn't move through the photo. When shooting water, I try to keep the shutter speed faster than 1 second. You will reach a point shooting waterfalls and flowing water where a longer shutter speed does not change the photo. The water can only become so smooth so weather the shutter speed is 15 seconds or 5 minutes, the photo will look the same.
These next 2 photos show the same location at different shutter speeds. The first one is at 0.7 second and the second one is at 111 seconds.
To get the correct shutter speed, you also need to understand how to use the histogram in your camera. This will let you know if there are blown out highlights or black shadows that are not recoverable in post processing.
Learning to use different shutter speeds can take your photography in new directions. One way to achieve long shutter speeds is with the use of neutral density (ND) filters but that is a topic for another post.
Now that you have the final part of the Exposure Triangle with Aperture, ISO, and Shutter Speed you can learn how they work together. Stay tuned for the next post and it will explain how to use the triangle for better photographs.
Randy Bott Photography