The function of a flash is to provide extra light especially when you are shooting in the dark. Skilled photographers use flashes to create optical illusions and heighten the image quality. They do this by focusing light at different angles or creating shadow lighting. But you need to be a good photographer to be able to achieve these results.
Most cameras have a built in flash whose power or angle cannot be changed. As a result most pictures taken with a flash have an underlined shadow caused by hard light. Red eye is another problem that a flash causes especially in close ups. Some of the cameras do have options to reduce the red eye but they do not eliminate it totally.
To improve the overall quality of the picture you need to get an additional flash attachment for your camera. Most digital camera manufacturers produce external flash attachments that can be added to your model. These flashes are referred to as dedicated flashes.
If you are using a dedicated flash then the flash is turned off automatically once it senses the right light exposure. It also controls the working of the in built flash and the attached flash. An added advantage of using dedicated flashes is that they can increase or decrease the intensity of the light beam while zooming. In this way it is possible to cover a wide area while retaining the quality of the picture.
Another type of flash commonly used by nature photographers and medical personnel is the ring flash. It fits around the lens and fires light in the form of a circle. This flash is the best for close up shots.
Hot shoe mounted and handle mounted flashes are two other varieties of external flashes. Of the two varieties, handle mounted is considered better.
Today, many digital cameras come with a PC or Pronto-Compur slot. This slot can be connected to the flash using a sync wire. It works by sending a signal via the wire that is intercepted by the terminal and the flash is fired. One of the biggest advantages of using this method is that you can experiment with lighting effects.
In most digital cameras flashes fire in a single line that is very close to the lens. Hence minimum effects can be produced in photographs. Using this method, the line of flash can be changed to a slight degree. This method works better when the camera is mounted on a tripod. Similar results can also be achieved if you have a hot shoe mounted on your camera. This can be done with the help of an adaptor.
As a precautionary measure it is best to use a voltage stabilizer since there are chances that high voltage can damage the sensitive parts of your camera. Another accessory commonly used is the flash bracket. It reduces the red eye to a great degree.
Since the flash drains battery, it is always advisable to have an extra pack of rechargeable batteries while shooting.