Introducing Flash Selection :
In a fast & ever changing world of technical field, I could mange to maintain my technique unchallenged for over a decade. The technique is called as flash-selection intended as a procedure for selection perhaps capable of live-matting. Some noted improvements during these time for eg, the RED, the forthcoming Canon camera capable of 4k capture, LED lighting, schneider lens capable of flash sync at 1/1600th.sec as Hardware, the HDR, Enfuse as software.
If I am not glorifying, ref page 61 of this external citation compares many of the currently used techniques and rates involving flash-Light for matting as the best technique.
titled Image and Video Matting: A Survey by Jue Wang and Michael F. Cohen
Flash-selection could change the shooting rituals, I mean making of a Movie, all those scorching halogen lights, or the very bright reflectors on a day light shoot will be reduced to minimal. Imagine flash-selection as a technique enable to utilise only 1/4~1/8th of lighting power for example a 2500~1250 watts of lighting replacing 10,000 watts [10kw] of conventional lighting that we would otherwise be using in a shoot. This technique further uplifts the efficacy and provides better power management for LED lighting which already replacing conventional lighting. The LED can be used as a flash aswell as a continuous source of light. It is meant a achievable target, that the LED can become to overpower a bright daylight enabled by a flash_sync speed of 1/2000thsec. Further the technique involves is selection and controlling in isolating the foreground from the background for special effect purposes, to modify lighting ratio, depth of field at post production, inherent capability comparable to HDR, Enfuse to extend Dynamic range.
We are aware a the built-in flash of a small pocket camera, a cell phone or a SLR camera is sufficiently bright for taking a picture than a prevailing light in a room of 100watt. My initiative is to use normal flash lights, the flash emitted by a LED, the reflectors etc.,.
The technique compares changes brightness between a frame exposed to ambient [ambient] room or exterior light, and another exposure where a flash lighting is combined with available light. when we use flash light to take a photograph the subject at the foreground receives more lighting than the background. The light that emerges from a small size of source like flash has an inherent nature to spreads the light more divergent. so there involves a drastic rate of reduction [fall-off] of lighting at various distance from the camera.
The flash synchronisation speed, is a word associated with flash lights to mean, the shortest duration of shutter speed that would make use of the potential of maximum power of the light discharged. Many of the digital SLR camera comes with maximum flash synchronisation speed of 1/250th second or even as short as 1/500thsec with focal-plane shutter .