Most cameras come with a flash, but an exterior flash will offer better control of the light. If you are considering adding one to your gear, here are some things to consider.
The guide number indicates the flash’s power. The higher the number, the more powerful the flash will be.
The number is determined by multiplying the flash to subject distance by the aperture for a well-exposed photograph. So if the best results are achieved when the aperture is set at f/11 and the subject is five meters away, the guide number will be 55. It is calculated at an ISO of 100.
Most photographers will want a higher guide number that will allow them to shoot at distances.
The exposure of the autoflash is determined by measuring the brightness of the flash illumination reflected from the subject. There are different types of autoflash exposures to choose from including:
TTL Autoflash: Through the Lens (TTL) autoflash is used by the built-in flash. So, when you press the shutter button, the shutter will open, and the flash will fire. The flash’s illumination is then reflected from the subject through the lens to the sensor that reflects it back to the base of the camera.
A-TTL Autoflash: This type of autoflash is calculated by a low-power pre-flash and ambient light. The flash’s output and duration are controlled during exposure. It is preferable to TTL as it provides the correct exposure at maximum range regardless of lighting conditions.
E-TTL Autoflash: E is for evaluative. It is so-called because it evaluates the ambient light and pre-flash illumination reflected by the subject. It determines the first ambient light reading from this second reading to get a flash-only reading which helps the camera determine the intensity of the flash for correct exposure.
Flash synchronization involves how the flash synchronizes with shutter speed. It can be as long as 1/1000 of a second or as short as 1/10,000 of a second.
There are ways to use the flash at higher speeds than the flash synchronization speed. This is a method called high-speed synchronization. It is achieved by increasing the duration of the flash, so it gives out a constant output ensuring you are always covered.
You can also opt for a slow speed synchronization which works better with a slower shutter speed.
Autozoom adjusts the flash output to the focal length of the lens. It ensures the flash matches the angle of view so there is no wasted light and no areas of poor illumination.
If you opt for a digital image sensor, it will detect the camera size to cover the field of view and ensure no power is wasted. This makes for a more accurate flash, a quicker recycle time, and more shots per set of batteries.
A wireless flash gives you the freedom to move around with your camera. It also allows you to synchronize the flash outputs, so you get the right amount of light on your subject. It uses a series of pre-flashes that fire automatically to allow the system to determine the required output. It then fires all units to provide a well-exposed image.
The recycle time is the amount of time it takes the flash to recharge after it’s been fired. Normally, this ranges from 4 to 8 seconds. The shorter the recycle time the better as it will allow you to take photos without having to wait a long time between shots.
An external flash can play a useful role in your photo-taking efforts. Now that you know how to find the one that’s right for you, you are ready to get some great shots. Which kind will you be adding to your collection?