3. You can use wider f/stops, such as f/5.6 instead of f/16, since wide-angle lenses have greater depth of field. This allows you to get a better balance between flash and available light
4. You have more creative lighting control. With the subject closer to the camera, the flash can be used to side-light or top-ligh
5. Since the lens-to-subject distance is typically reduced and the flash is usually held out and to the side of the subject, the particles in the water, or backscatter, are less illuminated by the flash.
6. An enhanced perspective can be achieved by placing the camera lens close to a small object in the foreground while including larger objects in the distance. In addition, focus brackets, which are found on some of the more advanced point-and-shoot and SLR cameras, allow you to critically align your focus on the small subject at the bottom or side of your image. The increased depth of field found on wide-angle lenses allows you to keep both areas in focus.
7. In available-light photography, a lower shutter speed can be used because blurring of your subject is reduced as the focal length becomes wider. A general rule of thumb states that you can hand-hold cameras at shutter speeds equal to or greater than the number in the focal length. For example, a 60 mm lens would require at least 1/60 second to minimize camera movement, while a 15 mm only needs a 1/15 second.
8. Wide-angle lenses allow you to shoot from positions not possible with a normal lens. For example, if you want to shoot a picture from the underside of a soft coral, it might be impossible to position yourself to frame the scene without damaging the reef. With a wide-angle lens, you can hold the camera under the soft coral from a safe distance and take the shot. With lenses such as the Nikon 15 mm, you can actually see the scene being reflected off the front element for framing. Digital shooters merely need to take a test shot, and then reposition the camera to get better framing.
9. Focusing is easier as the angle of coverage increases. Manual-focus lenses don't have to be exact, since the depth of field carries from inches to infinity when the lens is stopped down halfway. Autofocus lenses focus very quickly since the focus distance from its closest point to infinity is a small change on the focus indicator dial.
10. If you hold the camera out at arm's length and turn the lens toward yourself, you can take a self-portrait. We have even had fun with this to see just how many people we can fit in one self-portrait.