April Focus - ISO Speed

The speed of a film is the measure of how fast it responds to light. A low ISO speed means a film responds slowly to light, a fast ISO speed means the film responds quickly.

Since digital cameras do not use film but use image sensors instead, the ISO film equivalent is usually given.

What ISO denotes is how sensitive the image sensor is to the amount of light present. The higher the ISO, the more sensitive the image sensor and therefore the possibility to take pictures in low-light situations.

And, where you would have needed to physically change to a different roll of film if you wanted a different ISO speed, digital technology allows you to simply dial one in. In this way, you can record images taken at different ISO speeds on the same memory card.