Digital cameras with larger image sensors accommodate a wider range of ISO settings.
Digital cameras are more popular choices for most photographers for their ease of use. One reason is that film is not required to take pictures. But in many ways physical camera operation still mirrors that of film cameras. ISO offers one example of this.
ISO
ISO measures a camera's sensitivity to light. ISO is actually a function of the film in a film camera, not the camera itself. A digital camera's ISO is determined by image sensors on the camera instead of film.
Purpose
Lower ISO settings that are less sensitive to light are suitable for well lighted subjects. Lower ISO images are also finer grain. Higher ISO settings are more sensitive to light, so those settings can be used in much lower light situations.
Considerations
Photographers must carry multiple rolls of film to change ISO settings on a film camera.
Higher ISO settings are more effective in low light situations, but they produce grainier images. Lower ISO settings have finer images, but are ineffective when there is little light available. Also, changing ISO settings on a digital camera is as simple as selecting them from a menu, while photographers can only change film cameras' ISO settings by replacing the entire roll of film.
Operation
Most users use a digital camera's "Automatic" ISO setting. The camera automatically picks what it determines to be the lowest effective ISO setting. Photographers can also change this setting manually. Changing the ISO in a film camera requires changing the entire roll of film. It's generally a good idea to use the lowest ISO settings possible
