- [Instructor] The frame rate of your footage,
animation, or motion graphic,
is the number of frames per second.
This applies to recording footage in a camera,
editing, and playback.
As long as the recording speed and the playback speed match,
movement will appear to be natural.
It'll be the same as it was when recorded.
In the early years of cinema, slow motion effects
were achieved by capturing more frames per second
than would be played,
and since cameras were operated by a crank handle,
this was called "Over-Cranking",
and the phrase is still used today,
even though the image is usually captured digitally.
Interestingly, even though we're working with data now,
rather than silver halide on celluloid,
the principles of capturing a resemblance of a scene
and representing it for human vision,
haven't changed even slightly.
We have the same challenges,
and many of the same kinds of solutions.
We're just doing things with data instead of physical film.
Focus, exposure, and frame rate, apply just as much today
as they did when Man Ray was experimenting
with photo sensitive papers.
Our brains are pretty much completely fooled
by any still images that appear in series
faster than about 20 frames per second.
To create the illusion of movement,
you only need something in the region
of 15 or 16 frames per second,
but you'll still perceive the mechanical movement.
Over 22 frames per second, your eyes and your brain
will be fooled in to believing the movement is continuous,
or be it, sometimes imperfectly.
For quite a while, celluloid film was expensive
and dangerous, it could literally catch fire all by itself,
so filmmakers wanted to minimize the amount they used.
They added about 10% to the limits of human perception,
just to be on the safe side,
and 24 frames per second was set.
When video cameras came along, it turned out,
there was no easy way to accurately manage
frames per second to maintain sync.
The main power supply had a very stable alternating current,
so in the U.S. and other countries,
with a 60Hz alternating current,
video cameras recorded at 30 frames per second,
while in the U.K. and other countries,
were about 50Hz alternating current,
video cameras recorded at 25 frames per second.
Actually, if you recall our look into frames and fields,
the video cameras were actually recording,
60 Fields per second, or 50 Fields.
It was easy to use the alternating current as a reference.
Of course, we have much faster frame rates too.
The higher the frame rate,
the more fluid movement will appear,
and there's a limit to the number of frames per second,
the human eye can perceive,
but it's clear, doubling the frame rate,
gives an overall, smoother appearance of movement.
Cameras can usually easily record double the frame rate
for regular video playback,
and this option is commonly used by filmmakers,
just in case they want to achieve beautifully smooth
slow motion effects.
The limiting factor is always the playback.
Media production is about planning backgrounds.
If your final destination,
will be 24 frames per second film in a cinema,
you'll probably want to record footage in multiples of 24.
This produces cleaner speed change adjustments
in post production, because it's easier
to calculate the changes.
You're unlikely to produce video that's intended
to be played back with more than 30 frames per second.
So there's little to be gained
by recording at a higher frame rate,
unless you intend to slow the picture down later.
Obviously, recording at 60 frames per second,
and then playing back at 30 frames per second,
will give you lovely slow motion at 50% speed.
If you don't need the extra frames though,
it can save a lot of data storage by recording
at your delivery frame rate.