The Dangers of Flash Photography
One of the most important things to be aware of when doing flash photography is your camera flash's range. The camera flash will only reach areas of the composition that are within your flash's range. Knowing your flash's range, and staying within that range, is essential here. Subject matter that is too close will be overexposed. Often times almost all detail is lost when this happens. And, subject matter that is too far away will not get any light from the flash, and will appear very dark or even black.
Flash range is more complicated than it may initally sound. There is a distance associated with your flash's range, your flash can only work effectively within that distance. But, there is also an angle that your flash can reach. When using a wide lens, your camera will capture a wide area in front of the lens. Your camera flash often can not disperse its light enough to reach the corners of the area your are capturing in your photograph.
And, to make matters worse: if we were to be totally accurate, your flash range will not only depend on your camera's flash model. To accurately calculate the effective range of your flash, you also need to consider your film speed (ISO) and the maximum aperture of the camera lens you are using. For most amateur photographers, this info is too technical and not neccessarily too important. Generally speaking, if you are using a moderately fast film speed (ISO 400 and faster) you will get pretty good range out of your flash, especially if you are using a good quality lens.
While the intricate technical details and the results of improper flash usage can be compelling reasons to avoid using flash in your photos, remember that your flash can provide a lot to you. Flash photography can be tricky, but it is a skill worth developing. Often, as a photographer, you will find picture opportunities that will require a photographic flash.
Check out some more flash photography information.