Friday, August 02, 2013

Visual Hijinks: How is this so?

Why does the shadow in this unedited image cast a future action?
This image hasn't been photoshopped or digitally altered in any way. So why is the shadow so out of sync with the frisbee thrower's action?
It has to do with the way digital cameras work when set to scan from top to bottom.
Writing in the Blog of WondersMariano Tomatis explains:
The acquisition of this digital image is not recorded from a snapshot of a single point in time, but rather by scanning across the frame...vertically — starting from above. Not all parts of the image are recorded at exactly the same time, even though the whole frame is displayed at the same time during playback. This produces predictable distortions of fast-moving objects or when the sensor captures rapid flashes of light. This is in contrast with global shutter in which the entire frame is exposed for the same time window: the lower part is recorded a bit later, showing the disk already thrown.
Image: Blog of Wonders.

Thanks to Tony Duckett for passing on this one.

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