Camera Flash photography

Flash photography is basically photography with using flash light. There is a lot to play around with flash photography, however it mostly required an external flash as there is much limitation with the internal flash of camera. Hence, normally, external flash is one of the must have equipment in photography.

For flash photography, first we need to understand on how external flash function and its usage.

First, we need to know about "Flash Guide Number" (GN). GN basically determines the power of the external flash, how bright the light and the distance the flash can reach. The bigger the GN value means the more powerful the flash. The calculation is based on the formula below,

GN = F (aperture value) x m (distance in meter)
Note: the formula is base on ISO 100 as sensitivity setting.

Under this formula, if GN value is 40, it simply means that if we shoot the photo with F4 aperture, then the effective distance covered by the flash is 10 meter.

                       Some of the external flash available in the market nowadays.

Next, we take a look on the basic mode available in most of the external flash in the market.
1. M mode:
This is the manual mode and all the setting is based on user demand. In M mode, user has to decide on the GN value of the flash according to the Aperture setting and the distance of the subject. For M mode, as long as you have the value set correctly, then every photo taken next will have the same power of flash light. However, manual setting is time consuming and sometimes might be very troublesome and tricky.

2. A mode:
This is the automatic mode. In this mode, the external flash will meter on the environment, and then it will set the flash filling according to the aperture setting. A mode is almost similar to the M mode with the exception that the metering and the GN value are set by the external flash itself. User will only have to set on the aperture setting.

3. TTL mode:
TTL mode will depend on the exposure value metered by the camera. The flash will release the moment the shutter is pressed. If the metering system of the camera is good, it is best to use the external flash under this mode.
TTL however suffer when the environment has vast differences in brightness, either too bright or too dark. Under such situation, the camera might have metered incorrectly to be underexposed or overexposed. And without proper exposure compensation, the photo might be too bright or too dark.

4. FP High Speed Sync:
In focal pane high speed sync mode, the external flash is able to synchronize with the shutter speed of camera which is set to higher than the normal flash sync speed. However, in this mode, as the external flash flashes continuously, it causes the power to go lower.

Another thing to take note about external flash is the "angle of incident". For this, the external flash will cover the angle of incident according to the lens that is equipped. For most of the flash available in the market, the coverage for angle of incident is mostly from 24mm to 85mm which cover most of the wide angle to mid range.
Some external flash has diffuser available whereby when it is pulled, the angle of incident of that particular flash can reach to 16mm which cover most of the wide angle lensí coverage.



More about Camera Setting