Running out of battery is frustrating. The time or number of photos that a battery can last for is hard to predict and depends on the way the camera is used. For example the usage of the flash requires more energy thus taking photos with the flash enabled requires more power and thus empties the battery faster. Professional photographer usually carry a few fully charged batteries with them at all times to make sure that they never run out of battery. Although a good practice this is not always practical for amateur or casual photographers. An alternative is to be aware of what usage requires more power and to use the digital camera in a way that can save power and extend its battery life.

Different digital camera components require different levels of energy to operate. The digital camera LCD screen for example is one of the biggest energy consumers in any digital camera like the Digital SLR camera. The higher the brightness the more energy the LCD requires. If you want to save on battery make sure not to over use the LCD. In fact it is good practice to turn it off altogether by setting it to manual mode. Only use it when you must for example when you need to review a photo that was just taken or if you need to compose a photo and can not use the optical view finder.

The Digital SLR camera mechanical motors are also high energy consumers. For example using the motor to move the lens in order to focus or zoom requires energy. Although you can not avoid using the motors you can try to minimize the time in which they work. For example set the focus mode to single focus mode instead of continuous focus mode unless continuous mode is absolutely necessary. Also do not press and hold the shutter half way to focus unless you intend to shoot a photo. Any such focus activity without shooting a photo just wastes energy.

The Digital SLR camera flash also consumes a lot of energy. In some situations you must use the flash and thus can not avoid its energy consumptions. Sometimes the Digital SLR camera will fire up the flash although it is not really needed. If you know that the ambient light is strong enough and flash usage is not necessary then set the flash to manual mode to avoid unnecessary wasteful usage.

Holding the shutter button half way when you do not intend to take a photo is wasteful. The energy is wasted on the camera trying to focus by using the mechanical motors to move the lens. It is also wasted by a series of electronic chipsets that are woken up and set ready to take the photo. The camera electronic is usually kept at a very low power consumption unless it needs to be used. When the shutter button is pressed the electronics is put in high power consumption as it needs to be ready to capture the photo compress it to JPEG format and save it to memory.