What is ISO?

ISO SENSITIVITY:

ISO sensitivity is the digital equivalent of film speed. The higher the ISO sensitivity, the less light needed to make an exposure, allowing higher shutter speeds or smaller apertures.

ISO sensitivity can be set between values roughly equivalent to ISO 1600 in steps equivalent to 1/3 EV. Values over 1600 are displayed as H 0.3 (ISO 200 equivalent). H 0.7 (ISO 2500 equivalent), and H 1.0 (ISO 3200 equivalent). Auto and digital vari-program modes also offer an Auto setting that allows the camera to set ISO sensitivity automatically in response to lighting conditions.

The default setting for Auto and digital var-program modes is Auto, the default settings for P, S, A and M modes 100.

ISO sensitivity can be selected by pressing the ISO button and rotating the main command dial until the desired setting is displayed in the command panel. ISO sensitivity can also be adjusted from the shooting menu.

HIGH ISO NR:

The higher the ISO sensitivity, the more likely pictures are to be subject to 'noise' in the form of randomly spaced, brightly coloured pixels. Photographs taken at ISO sensitivities over ISO 1600 will likely contain appreciable amounts of noise. The High ISO NR option in the shooting menu can be used to reduce noise at ISO sensitivities of 400 or more.

Photographs taken at high sensitivities can be processed to reduce 'noise'.

Normal / Low / High - Noise reduction takes effect at sensitivities over ISO 400. Choose Low for less noise reduction. Choose High for more noise.

ISO AUTO:

This option can be used to enable automatic ISO sensitivity control in P, S, A and M modes. Sensitivities of H 0.3, H 0.7 and H 1.0 are not available when ISO auto is on.