When taking photographs you won't get a high quality picture unless you have enough lighting for the setting or situation. If there isn't enough natural light you may need to use artificial light or a flash unit, also known as strobe lighting. If your camera's built in flash isn't strong enough you can use a hand held unit. It may be hard for you to judge the amount of light available, so meters can be used to help you out. While some digital cameras may have built in meters, most film cameras need to use separate devices. There are various types of meters and some of these small, portable units will let you know how much light is available for your photo and what speed your shutter and what aperture or f-stop the camera should be set at. Meters can also tell you the color temperature of your light source among other things. Meters and lighting come in various sizes, and shapes.