ISO refers to how sensitive the camera's sensor is to light. The ISO camera setting is used to set the best ISO for your photograph.
Auto ISO: When this menu function is chosen, the camera will automatically, almost magically, select the necessary ISO if optimal exposure can not be achieved at the ISO value you've dialed in. Turn this feature ON, then just shoot away. You won't have to worry about lighting or shutter speeds - just concentrate on composition.
A recent post on our Exposure Control Lesson posed the question, What is ISO? Here's a more in depth explanation.
What is ISO?
What is the ISO standard and what it means to Photographers
ISO is short for International Organizational Standard. In the photographic world, ISO is most commonly referred to as a film rating system. Think film photography, not the movies In terms of film, ISO is used as a rating system to tell you how sensitive the film is to light, or how fast the film is. The lower the ISO number (ie 50) the more time the film needs to be exposed. The faster the ISO speed, less light is required to take a picture.
What is the Best ISO?
In many situations it is not possible to use a low ISO sensitivity setting. Such situations include those where there is low light and no tripod, or where the motion is very quick such; as in sports photography.
So What is ISO?
ISO is a standard telling you how sensitive your film/digital sensor is to light.
- Higher the ISO, the more sensitive the film/sensor is to light.
- ISO speed affects allowed aperture and shutter speed combinations.
- Higher the ISO, the more grainy or noisy pictures may appear.