You should recharge them when they are fully drained or they may lose some of their capacity. Some camcorders have features to prevent this from happening. Almost all camcorders have a visual indicator of how much power is left and come with the AC adapter for recharging the batteries and direct indoor use. Some models have an alkaline battery holder for emergency power from regular batteries. Nickel-cadmium batteries usually last about an hour.
Some models allow nickel-hydride or lithium batteries which can lasts twice as long.
Color viewfinders are found on a bit more expensive models. High-end camcorders offer LCD monitors which make it easier to shoot from angles or when moving, but drain more power from the battery. Almost all camcorders have zoom capability. Optical zoom works by increasing the length of the lens and offers superior image quality compared to high-magnification digital zoom. Some camcorders have more than one zoom rate, some have manual control of zoom rate, and few have an instant zoom feature, which instantly changes the zoom.