jueves, 6 de enero de 2011

High speed flash (part 3)

Besides capturing the moment of impact, as in my previous picture, I thought that I could also shoot exactly when the subject is in focus, which is specially difficult when the depth of field is small and the subject is moving.

In this picture I wanted to use a macro lens at the highest aperture in order to leave my hand (and maybe the second dice) out of focus.
I set up the laser and the sensor circuit using a mirror, mostly because I don't have much space on my desk:

I painted the laser beam on the picture. By the way, the laser is actually an infrared thermometer, though I'm only using it as a laser pointer. I'm using one clamp to hold the laser button down so it's on all the time, and another to hold it in place. The circuit is out of the picture, on the left side, behind the camera.

So I put the dice blocking the laser and prefocus the camera on them. Obviously the camera has to be in MF mode. Manual mode, 100 ISO, f/2.8 and 0.5 seconds exposure so I have time to throw the dice. 2 sec. delay mode helped since I was holding the flash with one hand and throwing the dice with the other. The long exposure is the reason why there is a red light in the picture. I'm not sure if it's light hitting the dice before the flash or a lens flare coming from a reflection.


Continue reading in part 3.

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