Nickel Metal Hydride rules
These batteries have almost taken control of the rechargeable battery market. Modern Nickel-Metal Hydride (Ni-MH) batteries have very low self-discharge rates compared to Ni-Cd batteries. However, the rate is affected by the temperature at which the batteries are stored and operated. Similar to Ni-Cd batteries, Ni-MH batteries can also cause charge reversal when one or more cells in a battery pack discharge completely. Some cameras detect the safe discharge voltage of the series of cells and shut themselves down. Once noticeable dimming or slowing of the device is noticed, it should be turned off immediately. Ni-MH batteries are comparatively safer for the environment rather than Ni-Cd batteries due to the absence of cadmium.

Getting ready-to-use Ni-MH
A new type of Nickel-Metal Hydride battery is now available. These have reduced self-discharge rates, and therefore have longer shelf life. Manufacturers claim that the batteries retain 70 to 85 percent of their capacity after a year of usage when stored at room temperature. These batteries are marketed as ‘ready-to-use’ or ‘pre-charged’. Brands like GP ReCyko, Sanyo Eneloop, Uniross Hybrio and VARTA Ready2use are examples of this.

What about Alkaline?
Alkaline batteries, which might have approximately 3000 mAh capacity at low current demand (200 mA), will have less than 1000 mAh capacity with a 1000 mA load. Digital cameras with LCDs and flashguns can draw over 1000 mA, quickly depleting alkaline batteries after a few shots. Ni-MH can handle these current levels and are better suited for digital cameras. Alkalines can come handy as second level batteries in case Ni-MH give up on you, especially in high altitude areas.

How to conserve power
Your digital camera draws a lot of power. So conserving battery power is as important as choosing the right type of batteries. The most power-hungry of all features is the LCD screen. So minimise the use of LCD by not playing back images or editing photographs in the camera. You can switch off the image review function or set it for a very small duration. Another important step is not to use the flash unnecessarily. If you are shooting on a bright day and you do not require flash, switch it off. Again, if you are not shooting in a very dark place, you can switch off the Red-eye Reduction function since Red-eye occurs in dark environments only, and the additional pre-flash used for this function can drain some power. If the scene is well-lit, you can even switch off the focus-assist light on your camera.

Keeping the above point will surely help you address the power-issues with your digital camera. If your camera uses AA sized batteries, the best option would be to buy Ni-MH batteries, preferably the new ready-to-use ones with good current capacity. Though these are not as cheap as the single-use alkaline batteries, the Ni-MH batteries can be recharged and used for a long time. The ability to recharge hundreds of times can save a lot of money and resources. As LCDs, flashguns and electronic viewfinders demand a lot of power, the alkaline batteries are of no use for digital photography. Dealers often supply rechargeable batteries and chargers with digital cameras to make the deal appear dearer. But most of the time, the batteries supplied will have very low capacities, typically around 700mAh. So, if you have a choice, do not accept the batteries and chargers supplied with the cameras. And last but not the least, choose a battery charger that can optimally charge your batteries.

Also read: Are you ready for a DSLR?