The equipment of almost every digital camera includes an integrated flash unit, which, however, usually has a relatively low output. The flash units are integrated into the housing near the viewfinder and are always ready for use. With better equipped digital cameras, the flash, which is usually located above the viewfinder, must first be folded out.
The maximum range of these flashes without a telephoto setting is usually around four to six meters. If the flash is used incorrectly, this can be seen in the photos in the best case, and in the worst case, the pictures are unusable. People standing particularly close to the camera can easily be overexposed by the flash. Strong drop shadows, which ugly frame a person standing in front of a bright wall, are also often seen when using flash. So flash is both a blessing and a curse. It depends on whether you know how to use a flash and a digital camera, and which flash function and flash intensity are appropriate at which point in time.
Brightening and softening strong contrasts
In many situations, such as at dusk, in sparsely lit rooms, or on bright sunny days when shadows are extreme, the flash helps brighten and soften strong contrasts by providing more light in the shadow areas. You control the ratio of daylight to flash by using the camera’s flash output compensation. With any reasonably modern digicam, you can adjust the power of the built-in flash up or down. Of course, this also works with an additional flash. For daytime fill-in flash, it is best to shoot in aperture-priority mode. In this mode, a shutter speed is set at which the images are not blurred – e.g. 1/125 sec. when shooting with focal lengths between 50 and 130 mm. When the shutter release button is tapped (not pressed), the camera determines the aperture required for correct exposure. Now the flash intensity is corrected downward by two steps using the flash output correction. Then all you have to do is aim at the subject and press the shutter release button.
Flash range and ISO value
The guide number of in-camera flashes is usually around 12 to 14. 14, which means that with a sensor sensitivity of ISO 100 and an aperture of f/2.8 subjects at a distance of up to about 4 m can still be illuminated well. The guide number for flashes always refers to the sensitivity of ISO 100. The higher the sensitivity (e.g. ISO 200, 400 and more), the further the flash output will reach. because with higher sensitivity, less light is required for correctly exposed images. correctly exposed images. Each doubling of sensitivity yields about 1.4 times the flash range. times the flash range.
To find out approximately how far your flash will reach at a set sensitivity of ISO 100, you can use the following formula:
Subject distance = guide number : aperture
For example, if you are using a pop-up flash with a guide number of 45, you could illuminate subjects at a distance of about 16 m at ISO 100 with an aperture of f/2.8 (subject distance = 45: 2.8). The smaller the aperture (large f-number), the shorter the flash distance. At aperture f/8, the range of a flash with guide number 45 at ISO 100 would only be about 5.6 m (subject distance = 45: 8).