Foundations: On-Camera Flash vs Flash Guns
Entry- and enthusiast-level DSLRs usually include an on-camera flash which pops up on demand or when using auto mode and shooting in low light conditions. Out of necessity, the flash is physically positioned only a few centimetres away from the lens, which causes a few problems, including ‘red eye’ and harsh, flat lighting. The flash emitted typically overpowers the ambient light, resulting in your subject looking like a rabbit caught in a car’s headlights. In addition, any reflective surfaces in your scene which are parallel to the camera will end up recorded as areas of white glare.
Although there are professional photographers (like Juergen Teller) who have developed a unique style around using on-camera flash, these images are notable for how unflattering they are. As he regularly photographs celebrities, the appeal of the shots is that the subjects don’t appear to be professionally photographed, giving the viewer a feeling of a private image taken by a close friend. For the majority of photographers, however, the main priority of a portrait is to flatter the subject, which is much more easily achieved with off-camera flash.
In low light situations, instead of resorting to on-camera flash, try raising the ISO, slowing the shutter speed and/or widening the aperture to let more light in. Experiment with other light sources – even a street light or a table lamp. If you end up using on-camera flash as a last resort, stick a layer of masking tape or white fabric over the cover of the flash to diffuse and soften the light slightly.
Flash guns offer many advantages over fixed on-camera flash. Their larger size means they can pack in more power, while providing you with accessible options to adjust and control that power. Their adjustable heads mean that the light can be bounced off walls, ceilings and other surfaces rather than just firing straight at your subjects.
Some have in-built or add-on diffusers, which soften and spread the light, and small white pop-up cards that reflect catch-lights into your subjects’ eyes even when the flash is angled upwards or to one side. You can buy mini soft-boxes and umbrellas for flash guns, enabling you to recreate flattering studio-style lighting on location, while still being much more portable.
Flash guns slide into what is called a ‘hot-shoe’; a metal mount positioned on the top of your DSLR which transfers data between the flash gun and the camera. A lever on the back of the gun locks it into place, ensuring it won’t slip off again. On the back of the flash gun is an LCD screen that shows the active mode, the effective range of the light output with the current settings and the camera and lens set-up.