What does long exposure mean? In simpler terms, it refers to a slow shutter speed.

The shutter in cameras operates at different speeds, which affects the speed at which the image is captured. It can be as fast as fractions of a second for short exposures or much slower for long exposures.
 

How do you capture images with long exposure? Practically, when you change the shutter speed on the camera, different numbers appear such as 1", 2", 4", 8", and so on up to 30" or even "BULB". These numbers represent the duration of the shutter speed, which can range from one second, two seconds, four seconds, and so on up to 30 seconds for the "BULB" mode.
 

*BULB: The shutter remains open as long as the shutter release button is pressed and closes when the button is released.
 

For example, if the shutter speed is set to 8", it means that the camera's sensor will capture everything for a duration of 8 seconds. Everything in the image will remain stationary, while moving objects will appear less sharp, depending on the number of seconds in the shutter speed.

In this type of photography, it is advisable to use a tripod because any camera movement will affect the image.
 

Example of a long exposure:
 

Photo credit: Husam Ghanem.