Google scientist Sam Hasinoff has come up with a technique called “light-efficient photography” that uses focus-stacking to reduce the amount of time exposures require. In traditional photography, increasing the depth of field in a scene requires reducing the size of the aperture, which reduces the amount of light hitting the sensor and increases the amount of time required to properly expose the photo. This can cause a problem in some situations, such as when a longer exposure would lead to motion blur in the scene.
Hasinoff’s technique allows a camera to capture a photo of equal exposure and equivalent depth of field in a much shorter amount of time. He proposes using a wide aperture to capture as much light as possible, and using software to compensate for the shallow depth of field by stacking multiple exposures. In the example shown above, the camera captures an identical photograph twice as fast by simply stacking two photos taken with larger apertures.