PCPhoto
Toolbox: FlashEnlighten your photography with the illumination of accessory flash |
Page 1 of 5 Compatibility is an issue when selecting an accessory flash. Some work properly with only their own systems, some play nicely with others, and some have features that work with only certain cameras. Before you buy, make sure the flash you want is right for your camera and needs. Guide Number The guide number is a representation of how much coverage is provided by a flash to illuminate a subject. Sometimes expressed in feet and sometimes in meters (be sure you know which), its determined by the distance to the subject, aperture (-stop) and the light sensitivity (ISO). While most flashes used with their proprietary cameras automatically adjust proper exposure, knowing guide numbers helps you with manual flash photography and also helps you to know when youre going to have flash falloffwhen there isnt enough light to cover the subject at the distance at which youre shooting. Metering TTL (through-the-lens) metering capabilities are essential for optimum results, so ideally youll select a flash thats compatible with your cameras metering system. Most flashes will work to sync automatically with the digital metering of the camera body, and most provide manual options as well. Some flashes also offer extras like AF illumination for autofocus assistance, particularly useful when its too dark to focus manually. Another convenience is auto-zoom flash, which allows a flash to adjust output based on your lens current zoom setting. |