Buyer's Guide 2007: Lighting For Digital Photography And Video
Improve the quality of your still and moving images with auxiliary light sources
Key Flash Features
One of the immediate advantages provided by auxiliary flashes is their wider angle of coverage. This is a big benefit if you're using wide-angle lenses of 24mm and wider. This eliminates the vignetting that appears in the corners of the frame when using the built-in flash. And with large lenses, it also eliminates the annoying shadow that can appear at the bottom of the frame when using the built-in flash at close distances.
The adjustable head of flashes like the Phoenix ZBIS-92 and Olympus FL-50 provides great versatility, as units automatically vary the zoom head to match the lens' focal length. Zoom from a wide 28mm to 85mm, and the flash will automatically narrow its output to match the focal length and increase its effective range. The flash head can also be swiveled or tilted to bounce the flash off a ceiling or wall when you want to avoid the look of direct flash. Some flashes, such as the Quantum Qflash, allow you to replace the head entirely with a variety of different light modifiers for even greater control over the quality of light.
Though taking the flash off-camera via a TTL-dedicated cord is typical, flashes are increasingly offering wireless TTL functionality. This allows you to use single or multiple flashes remotely but still retain the accuracy of TTL metering. Some units from Canon, Metz, Nikon and Quantum offer the capability of increasing or decreasing the output of these flashes while standing behind the camera, without having to physically move to each individual remote flash. You can also control multiple flashes arranged into groups.
This type of adaptability makes flash an effective tool, whether you're shooting portraits, close-ups or products.