The ISO scale indicates chemical film sensitivity to light:
ISO 100 – Low sensitivity, good for bright conditions, static scene, wide aperture and slow shutter.
ISO 1600 – High sensitivity, good for low light, dynamic scenes, small aperture and fast shutter.
Digital cameras exhibit similar noise at high grain levels.
This picture was used from google.
- Program mode (P) – Complete control of the ISO, camera will choose the shutter speed and aperture.
- Shutter speed (S) – Complete control of the shutter, camera will choose the aperture.
- Aperture priority (A) – Complete control of the aperture, camera will chooses the shutter speed.
- Manual mode (M) – Complete control of the aperture and shutter speed.