Oct 6, 2012

Calculated Magic

The talented M. came for my class the other day to be our model so my students could practice their skills. Well, after class we retired to the studio for our weekly Open Lab (when club members can come and use the studio or make prints or get tips on anything photography) and at the studio M. unleashed her skills. She's a dancer and a teacher and we really enjoyed working together to make some pictures in motion. I always love working with dancers, and I hope we'll have M. back soon.
Nikon D800, 105mm f/2.8 VR lens, f/4, 1/250s, ISO 640, Nik Silver Efex Pro 2.
Setup for this image is very simple, but required some math. In the studio I usually strobes--flashes--that give a very bright, very short burst of light. Working with more than one photographer doesn't work with strobes, though, because the flash is synchronized with the camera that triggers it and the others can't capture it at the same time. So this is captured using fluorescent lights that are very bright and stay on all the time. There are eight bulbs shining into two big white styrofoam reflectors. The light then reflects back onto M. very evenly. Still, those bulbs are nothing compared to the strobes, so in order to fairly freeze the action I turned up my ISO, brightening the picture and yielding a faster shutter speed--fast enough to freeze M.'s body, but still let her hair blur a little. If I wanted to freeze the motion more I might use 1/500 of a second for a shutter speed; twice as fast. But in order to keep the same brightness in the picture I would need to either open the aperture twice as large (one stop to f/2.8) or increase the ISO one stop, doubling it to 1250. In camera speak, 'one stop' is simply a doubling or halving of the light.

There's always an element of Mathematics in every picture, and when the moment and the equation meet...magic happens.

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