Exposure is one word for describing how much light the digital camera sensor is exposed to. There are two factors that set the exposure: the aperture and the shutter speed. Exposure is also described as one number called the Exposure Value (acronym EV). The two most important things to remember when taking digital photos is composition and lighting. One of the way to control the lighting in the photo is by setting the camera exposure. Setting the Nikon D50 6 1MP Digital SLR to a wrong exposure value will result in digital photos that are either over or under exposed. The exposure is controlled by two factors: the aperture and the shutter speed. The aperture setting controls how wide the lens opens up when the photo is being taken. The shutter speed defines for how long the digital camera sensor is exposed. Each combination of aperture and shutter speed defines a certain exposure value or in other words defines how much light the sensor is exposed to. Since the exposure value is controlled by a pair of numbers there is more than one combination that results in the same exposure value. Although from lighting perspective all those combinations are the same from other optical perspectives, for example the depth of field, they are different. It is important to emphasize that the exposure value is a number that represents to what extent the Nikon D50 6 1MP Digital SLR CCD sensor is exposed to light as opposed to how much ambient light is there in the scene. The exposure value number does not change with the scene lighting changes it is always the same even in complete darkness. The exposure value units are arbitrarily defined. It is a standard that exposure value 0.0 is defined as the exposure when aperture is set to f-number 1.0 and the shutter speed is set to 1 second. Other exposure values are relative to those settings. Usually you are not required to directly set the exposure value. The camera automatically calculates the exposure value needed based on the ambient light measured. It is more common though to set the aperture or the shutter speed or sometimes both. Some features in the Nikon D50 6 1MP Digital SLR are defined in exposure value units. For example exposure compensation or auto bracketing settings are defined in such units. Exposure compensation is basically telling the camera to lower or raise the exposure value when taking photos to compensate for errors in ambient light measurements, shades or just to get a specific lighting effect in the digital photo. When setting the camera to exposure compensation or auto bracketing you will have the option to define how much should the exposure value change. Usually exposure compensation does not change in more than five units. Auto bracketing allows you to tell the Nikon D50 6 1MP Digital SLR to take a few photos each time you press the shutter, each photo with a slightly different exposure value. You can also define the steps in which exposure value is changed. For example if you are not sure what is the right exposure setting, set it to the best you can or let the camera set it automatically and then set auto bracketing to take extra two photos or each photo taken one with exposure value lowered in 1 unit and one raised in 1 unit.
Digital cameras are great devices for capturing digital photos though they only work as long as their battery is not empty. If the battery is dry and you need to take a photo the digital camera will not work. There are ways in which you can extend your battery life here are a few. 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 Nikon D40 6 1MP Digital SLR. 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 Nikon D40 6 1MP Digital SLR 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 Nikon D40 6 1MP Digital SLR 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 Nikon D40 6 1MP Digital SLR 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.