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Gear

Gadget Bag: In A Flash!

Electronic flash units will add dimension to your photos

This Article Features Photo Zoom

Strobe. EFU. Speedlite. Speedlight. Flash. No matter what you call it, a portable electronic flash unit is one of the most important accessories any photographer can own. But many who mainly shoot outdoors overlook the possibilities. Flash photography is by no means restricted to inside!

Some of the best advice that can be given to beginning outdoor photographers when they ask how to improve their pictures beyond the snapshot level is “Turn your flash on outside.” Properly applied, a flash can brighten colors even in daylight, remove shadows from faces, add catchlights to eyes and enable early-morning and late-evening low-light shooting. A good one also can extend the range and accuracy of your camera’s autofocus system. Better flash units have a built-in AF assist beam that helps your camera focus in dim light by projecting a near-infrared ray that can be seen by the camera’s autofocus system.

In order to create light in sufficient and controllable quantities, you need an accessory flash. One that fits in your camera’s hot shoe will probably do the trick, although the larger handle-mount strobes are still popular in some circles.

Canon Speedlite 580EX II

Canon Speedlite 270EX

Most camera manufacturers offer two or three models, typically a small, medium and large option. Luckily for us, their model numbers often indicate their power. A throwback to the bad old days when flashbulbs and electronic flash units were manual, flash exposure settings once were calculated based on a Guide Number (GN). The GN was equal to 10 times the numerical value of the ƒ-stop that would yield correct exposure at a distance of 10 meters and at a given ISO. (Actually, it was ASA back then, and the distance was expressed in feet, not meters.) The higher the number, the stronger the flash.

In simpler terms, a flash that has a GN of 45 requires the camera’s lens to be set at ƒ/4.5 when the subject is 10 meters away. To determine which ƒ-stop should be set to take a picture at a different distance, divide the camera-to-subject distance into the GN. The GN system was so confusing for most people that the flash gun was often left in the closet after the first few mishaps. Today, everything is calculated automatically, but the GN is still important to know. All GNs in this article are in meters at ISO 100 except where noted.

Modern EFUs (as manufacturers refer to them internally) are powerful, automatic and simple to use. They differ by output power, physical size, bounce capability and angle of coverage. All but a few are powered by AA batteries (NiMH rechargeable cells are recommended).

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