When you’re photographing a wedding, there will be situations where light levels are low and you need to either use a high ISO setting or a flashgun. Since you’re effectively importing light with a flashgun, this will broaden your creative palette.
If you’re seriously considering taking wedding or event photos for a living, you’ll know that direct on-camera flash results in harsh light and shadows and the dreaded red-eye effect in your subjects.
To remedy this, mount a flashgun to the side of your camera and consider switching it to eTTL (Canon) or iTTL (Nikon) mode. These modes work intelligently with the camera’s exposure system to produce optimum results.
One aspect of flash photography that isn’t always understood is that the speed of the flash burst is much faster than the camera’s maximum flash sync speed. Thus, adjusting the shutter speed has a radical effect on how the final image looks, since it changes its level of dependency upon flashlight.
If you set the shutter speed to its fastest flash sync speed, for instance, you’ll often end up with a dark background because everything beyond the flash range is underexposed. Conversely, if you set a slow shutter speed, people and scenery behind the main subject will feature in the final image. These are two entirely different results.
Diffusing & Bouncing Flash
Photos that are lit mainly by flashlight will often look harsh, even if the flashgun is mounted off-camera. The way most pro photographers combat this is by fitting a diffuser over the head of the flashgun and/or bouncing light off a nearby surface for a softer effect.
When you bounce flashlight off a reflective surface of some sort, the color of that surface is carried in the light. This is why you’ll sometimes see photo assistants holding a gold-colored reflector next to a model – to warm the light and give a healthier look to complexion.