Digital Photography Tip Number 3....Underexpose dark scenes
Tip #3) Underexpose dark Scenes.... In contrast to Tip #2, if you have a dark or black overall scene, then set the camera's Exposure Compensation to underexpose the photo by -1/3 to -2. Most new cameras also have this build in photo setting also, like "Night Scene" or something similar. In a dark scene, the camera's light meter will look at it and try to get an overall neutral gray photo, so it will give more expose to the scene, making it too bright, and the blacks won't be grayish.
Great Deals On Photography Light Meters!
A common photo to get overexposed because of too much black in the scene is a group of men in tuxedos, like at a wedding. The camera will see all the black and expose to make the scene neutral gray, so then the black tuxedos are grayish and all the faces are overexposed and white as ghosts. So try to remember when there is lots of black in your viewfinder, underexpose the photo alittle.
Another helpful tip on this subject is that green/brown grass is really close to neutral gray, so your camera's light meter should give the correct exposure. Also, most scenes have a mixture of blacks, whites, and other colors, so the overall average color of the scene comes really close to neutral gray, so most of the time the camera's light meter will be accurate.
If you use an off camera light meter that measures ambient light, then you won't have the problems described in tips #2 and 3. It is just reading the light in the area and not the reflected light off of light and dark surfaces like your camera's light meter. The problem with ambient light meter is when you have a filter like a circular polarizer on your lens. You will have to adjust the ambient light meter reading to compensate for the filter. With a circular polarizer you would have to increase the ambient light meter reading by about 2 stops. If the ambient light meter said 1/250th at F8.0, then you would have to adjust your camera's exposure settings to 1/250th at F4.0, because of the 2 stops less light that the circular polarizer allows in the camera.
You could also set the ambient light meter ISO setting to something like 100, and then set your camera's ISO to 400 and then you could just set the camera's exposure settings to the same as the ambient light meters. You will get the extra 2 stops of light by setting the ISO 2 stops higher instead of using the shutter speed and aperture setting to get the 2 stops more light. This method problem would be easier and less confusing, because you just set the same exposure values in the camera as the ambient light meter.