"The D-BG4 Battery Grip extends shooting times by providing additional power via a second lithium-ion battery or AA batteries. The battery grip includes a tray for either battery option. It also features a vertical release button, depth-of-field preview switch, front and rear e-dials, and buttons for exposure lock and autofocus, as well as a green button and ISO button. The D-BG4 is weather-sealed to protect the battery. Please note that extra batteries are sold separately."
(Above photos taken with K20D and FA 50mm f/1.4 lens. Shot RAW and converted to JPEG for uploading to Blogger. Click on any thumbnail for a larger view.)