While you may be able to see a scene perfectly well with your eyes,
cameras do need a bit more light than our eyes in order to function
properly. You do not need any fancy hand-held photography light meters
for this step. The meter in your camera
will work perfectly well. Simply point your camera at your intended
scene and press the shutter halfway down. However, be sure that you
point your camera at the darkest part of the scene you are taking that
you want to be visible in your image. If you take a meter reading from a
brightly lit fountain, that beautiful oak tree behind it catching the
light will be too dark to appreciate. Take your reading from the oak
tree instead. Look at the readings it gives you. It may say that you
need a flash, or if you have a SLR, you may see the metering bar showing
you how much underexposed our image will be at your current settings.
*) source: http://photography.about.com/od/nightphotography/ss/NightPhotog_3.htm
