Batteries for Digital SLR & Mirrorless Cameras
Professional photographers will often keep back up batteries or attach their digital SLR cameras to battery grips to provide enough power to cover a day's shoot which may run into thousands of images. Digital SLR cameras require far more battery power than older 35mm cameras. A DSLR requires batteries which are powerful and long lasting to cope with writing data to memory cards, flash photography using the built in flash and viewing images and menus on the LCD display.
Most digital SLR batteries will last for around 300 images or more and this is sufficient for most photographers who may only take a few photos per week. In any event, it is always advisable to keep a fully charged backup battery to cover the unforeseen. The vast majority of modern digital SLR batteries are lithium ion batteries (Li-on) but some digital SLRs will still accept AA Nimh batteries which are plentiful & cheap.