Extended Battery Life: One of the primary functions of the D-BG8 battery grip is to extend the battery life of the Pentax camera it is attached to. Enhanced Ergonomics: The D-BG8 battery grip is designed to improve the ergonomics and handling of the Pentax camera, particularly when shooting in portrait orientation. Vertical Shooting Controls: To facilitate shooting in portrait orientation, the battery grip typically features duplicate camera controls, including shutter release button, front and rear control dials, AE-L (Auto Exposure Lock) button, AF (Auto Focus) button, and other customizable buttons.