At one time fast photography was accomplished with camera that
used focal plane shutters. The slit in the shutter travelled across the
film; the image at the top was taken earlier than that at the bottom of
the film (or left-to-right or the reverse, depending on how the camera was
held). Much commercial photography was taken with the Speed Graphic,
which used this type of shutter. Moving images were distorted, so we
became accustomed to elongated cars and slanted tires for speeding
vehicles.