Chapter 36. Flash programs

Irrespective of how the flash works, a camera has settings for flash photography. Most cameras use the functions and symbols on their LCD-screen, which are much like the ones shown below.

AUTO
In an automatic mode the flash is fired automatically when it is necessary. The light meter registers that a flash is necessary and it is activated quite automatically. More experienced photographers usually avoid automatic flash activation; there is a chance that it will go off at the wrong time. This can wear the camera’s batteries down, and it can be difficult to control exposure. It is better if you decide yourself whether or not a flash is necessary.

 FLASH-OFF
The flash is switched off here. Cameras, which have a pop-up flash, are much easier to work with. The flash only works when it is tipped up. You have to deactivate the flash in other cameras by pressing on a little button. In the worst cases you have to deactivate the flash in the menu system.

 RED-EYE
This mode tries to lessen red eye in images. This is done by firing off a little pre-flash before the real flash is fired. The idea is that people will close their pupils a little, so that red eye will dominate less. This effect is found in all cameras but it doesn’t work especially well. Luckily it is quite easy to remove red eye in an image processing program.

 FILL-FLASH
This mode always fires the flash off – regardless of the light conditions. It is a very good function, which you can often use outdoors, where it is a good idea to light people up with a flash. In some cases it can be necessary to weaken the flash manually with flash compensation by one of the diaphragm’s steps (1 EV) so that it doesn’t become too dominant.

The more advanced flash systems like E-TTL compensate themselves for daylight. If the flash is activated even though there is, in fact, enough light for normal exposure, then the flash strength is automatically reduced by between 0,5 and 2 EV, dependent on the assessed light measurement. You can really use the flash for fill-in in daylight here, especially if the camera can synchronise a flash with very short shutter speeds (1/250 second or less).

Choice of flash function via the menu system. (Minolta A1)

 Slow flash
This is a mode, which you can use for taking exposures in weak lighting, where both flash lighting and background light are in the image. The flash goes off for maybe 1/1000 second but the whole exposure takes, for example 0,5 second. Where the camera normally uses 1/60 second to synchronise the flash, it uses much longer shutter speeds to capture the subject’s natural lighting.

There are two variants of this mode: the first and the second curtain. The difference between them is the point of time when the flash is fired off. With the first curtain the flash is fired off right after the exposure is started. The lighting then continues for a certain time before the lens is closed.

The second curtain

”The second curtain” is a term, which describes the function where the flash is fired off at the end of the exposure time. It can, for example, be used when taking exposures of moving cars at nighttime. Here the car’s lights can be traced after the car, when the flash is fired off right at the end of the exposure time, and it looks better.

Flash compensation

Both fill-in and slow-flash are two sides of the same thing. In both cases the flash is fired off regardless of the lighting. It can be necessary afterwards to reduce the power of the flash. If the flash is too dominant, its effect can be weakened with flash compensation. You can, for example, weaken the flash with, what corresponds to two thirds of a diaphragm step (2/3 EV). So that the people in the image look less ”burnt out”.

The bottom scale in the display states the flash compensation, which can reach plus/minus 2 EV.