Look out for these key features when buying a flashgun. A wider range of features will expand your shooting options.
Many flashguns have a wide-angle diffuser panel to spread coverage when using ultra-wide angle lenses, and a reflector card for directing some light forwards in upright bounce mode.
Advanced flashguns can often be used as either master or slave units in multi-flashgun lighting setups, enabling you to get more exotic lighting effects.
A patterned grid of light, usually red in color, enables the camera's autofocus system to lock on to targets accurately, even in very dark conditions.
The most common motorised zoom range is 24 to 105mm but some stretch a little further.
Bounce and swivel head
This enables you to bounce light from the flashgun off walls and ceilings for a softer lighting effect. It's most useful for portraiture. A bounce range of between 0 and 90 degrees (horizontal to vertical) is usually available, and some flashguns add a -7 or -9 degree downward-slanting option for close-ups.
The flash tube fires a very bright pulse of light for a split second. The maximum available output is quoted as a Guide number.
An illuminated LCD info panel is useful for displaying important flash settings, or for arranging custom functions. The Metz flashguns on test go even further, with mono or color touchscreens.
On-board controls tend to comprise an array of buttons and dials. With the Nikon SB-500, however, adjustments need to be made via the camera.
This lets you position your flash wherever you like while keeping your hands free, and means you don't need a bulky lighting stand.