![]() For the latter option, people only need to shoot 16 frames per second (16x3=48, which is just above the minimum requirement described by Thomas Edison).Īs shown in the illustration, they utilized a triple-bladed shutter. ![]() A higher frame rate as such will require more film stocks, which is quite expensive.Ĭinematographers and projectionists came up with an ingenious solution: play the same frame twice or third times. So 46 FPS is the most suitable frame rate at that time? The answer is no, economically. Again, the persistence of vision blends the image into movement, without noticing the intermittent blacks when the projector is covered by the shutter. ![]() ![]() Then how fast is the minimum requirement to get rid of the flicker? 46 FPS and Triple Bladed ShutterĪccording to Thomas Edison, when viewing projecting images at 46 FPS or higher, we will perceive it as seamless motion without jittery or flicker. However, if you cover up the 12 frames intermittently with 12 black periods, there will be an intolerable amount of flicker since it keeps going black every other frame. To prevent blurriness, the solution is to prevent the switching of images to be projected. Although any rate above 12 will be perceived as motion, there will be a blurry mess when the individual image is loaded to the projector. It takes time to hand crank the film strip in place. Now that we know anything above 12 frames per second will be blended by our brain as actions, then why the 24 FPS? Or 25/30/60 FPS? How does the number come from?īefore we enter into the digital era, the film is played with a projector. When the light is removed in front of the eye, the visual is still perceived by the human eye for some time, creating an optical illusion. Physiologically, it is made possible by what is now termed as the persistence of vision. This phenomenon was discovered and described by Max Wertheimer in Gestalt psychology in 1912, and was termed as the phi phenomenon. Any sequence higher than that is perceived as motion, in other words, our brain creates a sense of movement when viewing these images flash by. Human eyes can deal with 10 to 12 images per second without mixing them up, meaning we can see each image separately. He accidentally discovered these image successions can reproduce the action, as if the horse was galloping in real life. In 1877, when Eadweard Muybridge was researching horse walking and running, he set up multiple cameras to capture a series of pictures taken chronologically. Interestingly, the discovery of creating the motion illusion via moving pictures was a happy coincidence. We already know that the film is in fact a series of still images, and the seeming motion is nothing but an illusion. Why the numbers are chosen as such? What frame rate should you use for certain occasions? Before diving into the detail, a little history of the frame rate can make things clear. Since frequency can be used to describe a repeat event per second, FPS may also be called frame frequency, with 1 hertz (Hz) signifying 1 frame per second.Ģ4 FPS, 25 FPS, 30 FPS, 50 FPS, 100 FPS, and higher ones are commonly seen in camera settings, video editing software, motion graphics and VFX software. Therefore, frame rate is also alternatively expressed in frames per second (FPS). In most cases, that unit time is one second. Frame rate refers to the number of frames being captured or played back every unit time.
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