Multiple exposure involves imposing two or more exposures in a single image. This technique allows effects like ghost images or combining images with different exposures. The example uses a portrait of a woman combined with an image of a forest, allowing both subjects to be visible. High speed photography captures very fast phenomena by taking photos rapidly to reduce motion blur. It is used by the military to study weapons and scientists to examine physical processes. One early example from 1856 captured cannonballs in flight at an exposure of 1/50th of a second, an impressive speed for the time. The example shows a strawberry with parts flying off after being shot, revealing details not visible to the naked eye.