Slow Motion Effect Research

Slow Motion was invented by the Austrian priest August Musger in the early 20th century. There are two ways that Slow Motion can be achieved :

-Over cranking

-Time Stretching

Overcranking

Overcranking is when the film is being shot in a higher frame per sec
ond than normal, so when played back in a normal speed, the scene is in slow motion. So a normal frame per second would be 24, if you then overcranked to 120 frames per second it would then be shown at 1/5 of its actual speed.

Modern slow-motion footage is shot with digital cameras that have a very high frame rate, rather than film, but the principle is the same, the footage is slowed down to 23-30 frames per second where it plays in slow motion.

 

Time Stretching

This type of slow motion is done in post production. In this type of slow motion, you insert new frames in-between the frames that have actually been shot. The end result is similar to overcranking as the motion occurs over a longer time than originally shot. Since they were never actually photographed, these frames must be fabricated. This can be done by coping the previous frames. However its usually done by interpolating between frames. This interpolation is usually basically just a short dissolve between the still frames. Many complicated algorithms exist that can track motion between frames and generate intermediate frames that scene. It is similar to half-speed, and is not true slow-motion, but merely longer display of each frame.