Adjusting Flash Power for Your Digital Photos
When you use flash, the digital camera automatically sets the flash power according to what it thinks is necessary. But many cameras enable you to adjust the strength of the flash light through a feature called flash exposure compensation, or flash EV.
This feature works just like exposure compensation, which adjusts overall exposure to produce a darker or brighter image, but instead varies the strength of the flash. Usually, the option is represented by a little plus/minus symbol alongside a lightning bolt — the universal symbol for flash.
It’s easy to use: As with exposure compensation, settings are stated in numerical terms, such as +1.0, –1.0, and so on. If you want more flash power, you use a positive flash EV value: +0.3, +0.7, and so on. For less flash power, you select a negative value.
Here’s an example of how this feature works. This picture was shot at an outdoor farmers’ market, in a stall that was shaded by a large awning. Adding flash would bring a little more light to the scene, but at the default flash power, the flash light was just too hot, blowing out the highlights in the fruit. So the flash power was reduced by setting the flash compensation value to –1.3, which added just a small pop of light without overpowering the subject.
For advanced photographers, some cameras also offer manual flash power control. If you go this route, the camera doesn’t take any role in setting flash power; you dial in exactly how much flash power you want to use.
In addition to using these flash adjustments, you can diminish flash power by using a mechanical solution: Place a diffuser over the flash head. For example, you can see a diffuser below which is designed to work with the pop-up flashes on dSLR cameras. The diffuser is made by LumiQuest and sells for under $15, but you can find other styles of diffusers for built-in flashes and also for external flash heads.
Regardless of the style or size, the idea is to spread and soften the flash light, helping to eliminate harsh shadows and create more flattering light. If you do much flash photography, especially portrait photography, adding a diffuser to your camera bag is one of the best investments you can make.