Sunday, November 23, 2014

Creative Flash 3 - Freezing Action

Cyclists In Central Park

Still photography has a dynamic relationship with movement. Photographs can freeze fleeting instances that our eyes cannot perceive, or they can stretch time and render movement as blurs or streaks.

A fast shutter speed combined with a lightning fast burst of flash can freeze fast-moving subjects like these cyclists. But this type of shot presents a technological problem that you might not expect.

a photograph of cyclists riding in central park new york
Speeding Cyclists - Central Park

When the camera's focal plane shutter moves at a high speed, it's never completely open. Rather, it slides across the frame like a narrow open slit. A normal burst of flash would illuminate only the part of the where the slit is open. The rest of the frame would remain dark.

(Note: There are special lenses that work around this problem by mounting the shutter in the lens, rather than in the camera. But these lenses are not designed for use with most cameras.)

Luckily, the brilliant engineers at Nikon and Canon have come up with a solution for the flash over speeding shutter problem. The flash doesn't just fire once; it fires several times in rapid succession. 

Flash! Flash! Flash! 

If everything is synchronizes properly, you can freeze motion at a very high shutter speed while adding the creative power of flash to the image.

The cyclist photo was shot with a shutter speed of 1/1600th of a second, which is about six or seven times the typical maximum shutter speed for flash photography. Nice work, engineers!

: Nikon D800E
Lens:     Nikon AF-S Nikkor 24-70mm f/2.8G
Flash:    2 x Nikon SB-910 / SU-800 commander

Light happens.  Be ready.  Shoot hard.

Copyright © 2014 Daniel R. South
All Rights Reserved

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