Paul Jolly Photography Chapter 4

Exposure Time

This is where we can balance the loss of light due to aperture changes with the time we expose the sensor. Remember for the correct exposure we are controlling the amount of light through the lens multiplied by the time it is allowed through to the sensor.
The side effect of the exposure time is how motion in the scene is captured, a short exposure time can stop motion and make the picture look sharp, great if you tend to wave the camera about a bit when you take a shot, but can make the moving object appear unnatural.

The photographs on this page are of water droplets falling from the same height; illuminated by the sun. The background is black card. Some side blurring of the droplets can be seen in the 1/100 second exposure due to turbulent air modifying the movement.