High-speed sync is a special flash mode that can overcome the limited flash synchronisation speeds of focal plane shutters.
Watt-seconds is the usual measurement for the power output of professional flash systems. 1 watt-second is equivalent to the power of 1 watt for a period of 1 second. It’s used because it’s a measure of raw power output independent of any lighting modifiers, angle of coverage or reflective surfaces
Flash duration is the length of time a flash is generating light. The flash duration is typically very short, often between 1/500sec and 1/1000sec, but often even faster than that.
The recycle time is the time taken by a flash to build up the power for the next flash after it’s just been used. Flashguns work by accumulating a large electrical charge which is then discharged in an instant via the flash head.
A cable connector for socket external flash units that’s still found on higher-end cameras like pro DSLRs but is becoming less and less common as photographers switch to wireless flash systems. These are usually triggered by a ‘master’ unit attached to the camera.
The names used by Nikon and Canon respectively for their camera flash units, both built-in pop-up flash and external flashguns. There’s nothing intrinsically different about these compared to regular flashguns – it’s just a different choice of name.
Special flash mode where the camera’s exposure is extended beyond the brief burst of the flash. This makes it possible to record some of the ambient lighting too, and it’s a popular technique for illuminating a nearby subject brightly without losing background colour and detail.
A special slow sync flash mode which fires the flash at the end of the exposure not the start. This gives more natural-looking results with moving subjects because any movement trail will be behind your subject and not ahead of it (which looks odd).
Most cameras have a built-in flashgun which pops up automatically in low light or can be popped up by pressing a button. The flash can provide emergency light, but it’s harsh and short range. In many instances it’s best to leave the flash off and use higher ISO settings.
Accessory shoe on the top of more advanced cameras that’s designed for sliding in an external flashgun, though these days it may also be used for electronic viewfinders, wireless remote control units and more.
A measure of the power of a flashgun, whether it’s a built in flash or an external flashgun. You take the guide number and divide it by the subject distance in metres to get the lens aperture you should use. Flash power is usually controlled automatically these days, though, so the guide number is just […]
A mode where the flash is made to fire whether the light is low or not. Normally, the camera won’t fire the flash in bright light, but forced flash mode overrides this. Flash can be useful for fill-in light for portraits, even in daylight, and especially if your subject’s face is in shadow.
Digital SLRs and compact system cameras use focal plane shutters and these have a design limitation – there is a maximum speed at which the whole sensor is exposed at once. This is the maximum flash synchronisation speed. Beyond this, the sensor is exposed in a moving strip, which is no good for flash.
Flash power is usually handled automatically by in-built flashguns and external flashguns. The exception is studio flash, where you adjust the power manually in fractions of full power. 1/1 is full power, 1/2 is half power, 1/4 is quarter power and so on. Some smaller flashguns offer manual power settings too.
Flash power is normally handled automatically by the camera, but you can increase or reduce the flash power with the flash compensation option – it’s just like using the exposure compensation option with automatic exposure.
Flash is the most popular artificial light source for both amateur photographers and professionals. It delivers a short, intense burst of light that can freeze moving subjects and illuminate objects up to a few metres away. Many cameras come with a built-in flash, but it’s also possible to add a more powerful and versatile external […]
A flashgun designed to clip to the top of the camera on its accessory shoe or to be used off-camera and fired remotely by cable, radio control or infra-red. External flashguns have more power than the camera’s built-in flash and a lot more flexibility in the way you can control and direct the light.
Wireless flash system used by Nikon to control one or more external Speedlights from one place. Speedlights can even be combined in ‘groups’ for more power or more sophisticated lighting effects.
A flash control mode on some Nikon DSLRs and external flashguns (Speedlights) which can fire other Speedlights remotely via infra-red. It’s possible to control quite complex lighting setups in this way, and it’s part of Nikon’s CLS (Creative Lighting System).