Learn Digital Potography..Digital Camera Flash Units

Digital cameras flash units come in many shapes and sizes. Low end digital cameras include low energy built in flash units. High end digital SLR cameras can support sophisticated external flash units which can provide superior lighting in difficult scenarios. Here are some basic facts about flash units both built in and external.

Many advances have been made with flash units since the early days of photography. In photography's infancy, flash units were using powder that was lit by electrical current and then "blown up" to generate the light energy. This method was most certainly a risk. It also proved a challenge as the flash units were not automatically in time with the camera's shutter so the photographer had to coordinate the flash to go off at the exact time the photo was shot.

Nowadays flash units are sophisticated technology devices. They use an electronic flash tube that is automatically synchronized to the camera. The photographer merely needs to do nothing. New digital cameras can decide on their own if the flash is needed, they can set its intensity and other parameters and they can fire the flash at the exact right time when the shutter is opened. All this is done automatically in the background. Digital camera also provide the user with the ability to manually control the flash, force it to either fire or not to fire, set its intensity and more.

Flash units are separated into two basic categories: Internal built-in flash units or external flash units. Internal flash units are naturally built into the camera. Nearly all digital cameras come with such a unit and permit the user some control over it through the camera's menus and buttons. External flash units are attached to the camera's body through a dedicated slide-in slot or by using an electrical cable. Not all digital cameras can support external flash units. Generally the lower end pocket cameras do not support external flash units while all high end digital SLR cameras will. There can be quite a bit of difference in external flash units. They can have different light energy levels that they can emit and different mechanical characteristics. Some external flash units also include smart sensors to measure ambient light, distance and other optical parameters in order to make the most of the flash effect.

Flash units can be used in both automatic and manual mode in most digital cameras. When in automatic mode, the camera measures ambient light and fires the flash when there is a lack of enough light. There can be times the camera will make the incorrect choice in using the flash and will either fire or not fire the flash when the contrary was needed. Setting the flash intensity is important also. Should the flash unit fire too much light energy on objects that are too close to the camera the digital photo will be washed out. Of course if the flash unit fires a small amount of light energy on an object that is farther away from the digital camera the digital photo will be a too dark.

Flash units have limitations too. They can not light any scene and any object at any distance from the camera. It is important to know your flash unit limitations. For example check what the maximum light energy that it can emit is and what the farthest that an object can be effectively lit from. This is also known as the effective flash range. If the object is out of the effective flash range it is actually better to turn off the flash altogether and use a tripod with a longer exposure. Sometimes it is useful to use the flash even if there is enough ambient light. In such cases you can manually force the camera to fire the flash. This is also known as fill-in flash as it is usually used to fill-in shadowed areas on objects in the digital photo.

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