Freezing the movement
When using flash lighting as your sole or principal source of illumination, you can take advantage of its movement-stopping characteristics to create unusual action portraits that are full of “frozen” energy.
For example,if you use a flash- synchronization speed of 1/60 , 1/125 or 1/250 second at f11, your subject would be recorded by light from the flash alone (without flash, a shutter speed of 1/30 or 1/15 second would be necessary for correct exposure and this combination of 1/250 at f 11 would render it underexposed). As we know that higher shutter speed of the camera freezes the action because the subject gets registered only durring a very brief moment as it moves long. With flash that brief exposure is provided by the burst of flash and not just by the shutter speed of the camera. If these is no available light or insignificant available light, it has no influence on the exposure. The “freezing” power of this technique stems from the fact that flash units – studio units, add-on flashguns, or built-in types found on amateur SLRs and compact cameras – deliver a burst of light of extremely short duration. The longest flash duration from a small unit might be only 1/1000 second, while larger units might deliver light in 1/10,000 second bursts – brief enough to stop any normal subject in its tracks. Some of these high speed flashes in sync with higher shutter speeds can freeze very fast movements as well.