BATTERY LIFE
AA-Size Battery Compatibility
AA-Size is one of the most widely available battery sizes in the world - in alkaline, lithium, rechargeable or other forms. AA compatibility enables use anywhere in the world.
There are certain things that users can do to help with battery life. The most important is to set the camera to turn the LCD off after a short time, during periods of non-use. It can then be automatically turned back on if you depress the shutter release control half way. Please refer to the PowerShot Instruction Manual for details on how to make this adjustment setting. It is always wise to have backup batteries in case you do run out of power. The supplied battery can be recharged many times and offers an economical and environmentally friendly power source.
USING THE FLASH
The PowerShot has a built-in flash, which will illuminate nearby underwater subjects. For subjects that are farther away and for deeper dives, an accessory slave flash is recommended (see below). A built-in flash diffuser is supplied which will help achieve a wider and softer light source, thereby providing more coverage and less likelihood of backscatter (the unattractive snowstorm affect of the flash reflecting off the suspended particles in the water). Further reduction of backscatter can be achieved by using an accessory off-camera slave flash. This will be discussed below in more detail later.
The need for artificial light to maximize color reproduction is necessary in nearly all pictures taken underwater. Therefore it is strongly recommended that you set the flash mode to Flash Always. This will ensure the flash fires on every exposure regardless of the ambient light conditions (Please refer to the camera's instruction manual for more details).
Outdoor photographers do not have this same problem. There is no backscatter to be concerned with, and due to the ability of the flash to travel farther and more effectively in air as compared to in water, there is
normally not a need for an accessory flash to provide proper illumination for most subjects. 13
