DSLR cameras and some point and shoots offer the following modes:
P Mode is the Program Mode, which is almost the same as the fully Automatic Mode, except for the possibility of changing the ISO (sensitivity of your sensor) and White Balance, the Flash can also be turned off in this Mode.
Av Mode allows you to control the depth of field in your image, basically the range of objects in sharp focus. In this mode, you select the aperture and the camera determines the shutter speed. With a small aperture (a large number), more objects appear in focus. With a large aperture (a small number), fewer objects will appear in focus.
TV Mode allows you to control how motion is portrayed in your image. In this mode, you select the shutter speed, and the camera determines the aperture. A fast shutter speed (a high number) freezes action, while a slow shutter speed (a low number) blurs the subject.
M Mode allows you to control how motion is portrayed and/or the depth of field in your image in your image, and to overwrite the suggested exposure by the camera. You will see a scale on the bottom of your viewfinder, which has a range from -2 over 0 to +2. 0 indicates the “proper” reading of the cameras light meter for a correct exposure – will underexpose + will overexpose the image.
It’s a good idea to master these modes so that you are prepared to adjust your settings to capture the best photos in a given situation.