By : Nikon School Blog | 10 Apr, 2018 |
A flash is a device that provides the camera a light source whenever required. Whether the built in flash is used or an external one, understanding the fundamentals of flash photography is vital to how effectively you can use it. Here, we shall discuss a few common flash photography terminology and the main flash modes to help you get the most out of the built in and external flashes in Nikon system.
Common flash photography terms :
Guide number : this figure is mentioned in the specifications of any flash, and is an indicator of the power of the flash, and the distance over which the flash can illuminate. GN can be calculated with the following formula –
Guide number (GN)=distance (meters) × aperture (f-number)
Guide number can be used to calculate how close the subject should be at a given aperture for a subject at a given distance. For example, if the flash unit has a guide number of 12 at ISO 100 and aperture is set to f/4, the subject can be up to 3 m away.
GN value increases with increase in ISO value, so the area of coverage also increases.
Flash duration : this is the duration for which the flash emits its light. This value is key to freezing very fast movements, like a balloon bursting. Flash duration decreases with every decrease in output. The SB 5000 has a flash duration of 1/980 s at full output 1/1110 s at half output. Automatic flash control is done by adjusting the flash duration, usually between 1/1000 to 1/20000 second.
Flash Sync speed : It’s the speed at which a flash synchronizes with the opening of the shutter. This speed varies with DSLR model, but is usually 1/200 or 1/250.
High speed sync : If Auto FP high speed sync setting is activated, (if camera supports) then flash will be operational at higher than standard sync speeds (only with compatible external flashes).
Recycle time : the time it takes for the flash to be ready to fire after firing once. Recycle time is more when the flash fires at a higher output.
TTL Mode : Also called i-TTL in Nikon system, this intelligent and lightning fast system emits pre-flashes which bounce off objects in the frame to tell the camera’s i-TTL flash sensor precisely what the optimum flash output should be to illuminate the scene uniformly.
Manual flash : The flash output is controlled manually in this flash mode. This works best when shooting in manual exposure mode, and the same flash output is required for a long durations.
Bounce flash : External Nikon speedlights generally have a tilting head which can be used to bounce the light from a ceiling or walls etc. to create a softer, pleasing effect instead of a much harsher direct flash.
Fill flash : When flash is used to fill in the shadows on a back-lit subject.
DSLR Flash modes
These are the flash modes found in all Nikon DSLRs. These modes work with both the built-in-flash and external speedlights.
Fill flash : the flash fires immediately after the shutter release button is pressed.
Red eye reduction: The red eye reduction lamp lights up before the flash fires, reducing ‘red-eye’ effect in the eyes.
Slow sync. : Slow shutter speeds are selected by the camera to exposure ambient light along with the flash. Very useful for including background lighting in portraits. Can be selected in P and A modes.
Rear curtain sync : the flash fires just before the shutter closes. This helps record movements, before firing the flash, so that any light trails are formed after the subject and not before it. Useful to capture moving subjects, in low light.
While starting flash photography is fairly simple and easy, flash photography is a genre in itself and mastering advance operations takes years of practice.