mah stands for milli amp hour. So if you have 2000mah batteries then they will(should) allow you to use the power at the rate of 1amp for 2 hours i.e. 2hour battery life or pro rata. So the highrer the mah the longer the batteries will power your camera between charges. Of course they should last longer as you camera will not use power at that rate. More functions on the camera means more power needed. If you leave the screen on all of the time your batteries will not last aslong as if you used the screen only when needed. Sorry if this is long winded but I hope it helps.