Minolta 7i instruction manual Camera Sensitivity ISO

CAMERA SENSITIVITY – ISO

Five settings can be selected for camera sensitivity: Auto, 100, 200, 400, and 800; the numerical values are based on an ISO equivalent. ISO is the standard used to indicate film sensitivity: the higher the number, the more sensitive the film. See setting the function dial section on page 44 to change the ISO setting.

The auto setting automatically adjusts the camera sensitivity to the light condi- tions between ISO 100 and 400. When the flash is activated and camera sensi- tivity is set to auto, the ISO value is set between ISO 100 and 200. When any other setting than auto

is used, “ISO” will appear on the data panel, and “ISO” and the set value will be displayed on the monitors.

Photographers can select a specific sensitivity setting. Like grain in silver-halide film that increases with speed, noise increases with sensitivity in digital imaging; an ISO setting of 100 will have the least noise and 800 will have the most noise. A change in ISO also affects the flash range (p. 66); the higher the ISO, the greater the range.

As the ISO value doubles, the camera sensitivity doubles; changing the ISO between 100 and 200, 200 and 400, or 400 and 800 changes the camera sensitivity by one stop or 1 Ev (p. 151). A change between 100 and 800 changes the camera sensitivity by a factor of 8 or three stops. High ISO set- tings (400, 800) will allow the photographer to hand hold the camera in low-light conditions without the need of a flash.

Camera Notes

When making bulb exposures (p. 53), noise can be more pronounced because of the unusually long exposure times, especially at 400 and 800 ISO. When making long bulb exposures of 20 to 30 seconds, a camera sensitivity setting of 100 or 200 will produce excellent results. At higher ISO settings, using shorter exposure times (8 – 16 seconds) will reduce the effect of noise. With long exposures at high ISO settings, noise from interference may be noticeable.

65