The camera integrated flash is a powerful and useful source of light that cope with most of the situations for indoor photos where distances to the subjects are usually small. Night shots are almost always done outdoor where distances to the subjects are quite large and the integrated flash is not powerful enough to cope with these. The flash will light anything that is within a few feet of the camera but anything beyond this will not be lit with the flash. A more powerful source of light is needed and this is the flashgun, but even this may not be enough for very large distances.
For night photography one way of overcoming a flashes lack of distance with a flashgun is to light various elements in the scene by using the flashgun off the camera. This technique requires the photographer to have close access to the subjects in the photo and enough time to get there and fire the flashgun. For example, in a very dark area you can set the camera on “B” mode and while the shutter is open the photographer will go near to all the subject in the photo and fire the flashgun using its “test button”. This usually requires two people, one will hold down the shutter button (a locking cable release is a better option) and the other will fire the flashgun. If there is very little ambient light you don’t have to worry about crossing in front of the camera as long as the flashgun will not lit you. The whole exposure will easily exceed 30 second which is not actually a very long period of time to get with the flashgun to to all the subjects, but if you succeed you can obtain some great night photos.
Artificial light is the main source of light for night photography. These lights have a much different color cast than midday light, and to make things more complicated, different artificial lights has different color casts. In a night photo we can have multiple sources of light which give off different color casts. Fortunately we can change the color cast of light source by using the White Balance setting in the camera. This gives an even further amount of creativity in taking the photo.