The power need for digital cameras is very high. As they get smaller in size, the challenge has been to come up with a battery that would meet those requirements and still be small enough to fit into the smaller digital cameras.
No one would be happy with a camera that didn't have enough power to run it for a reasonable amount of time. There are two divisions of batteries for digital cameras, and these divisions are very broad:
* Off-the-shelf batteries While a few cameras have AAA batteries, AA (or CR2 batteries) are the more common in use. These are lithium-based and are intended for only single use; they are also commonly seen in camcorders. The alkaline battery, which is nonrechargeable, provides only enough power for a very short time in most digital cameras. Most photographers have moved to the AA nickel metal hydride batteries along with a charger; these provide the necessary power and can be easily recharged. Mid-range and low-end cameras may use off the shelf batteries, but only a few cameras (DSLR) accept them.
* Proprietary battery formats These are the second type of battery. Specifically built to the manufacturer's specifications, they can be either OEM or aftermarket replacement parts. Most of the proprietary batteries are lithium ion. The battery life begins to degrade after a certain number of charges, usually about 500 cycles; yet they are very powerful for their size. Because of this, both high-end professional cameras and consumer models at the low end have lithium ion batteries.
Digital photographers, both professionals and amateurs, will find many types of batteries available; all will be within the two categories mentioned above. It is possible to find as many opinions about the type of battery to use as there are photographers using them. Only the consumer can actually make the decision about which they choose.