Fun With Frame Rates

Frames are still a thing?

Have you ever wondered what makes those slow motion scenes in a movie like Reservoir Dogs so cool? Have you ever thought about it what it takes to create an epic time lapse shot like those in the opening credits of House of Cards? The answer lies in frame rate. And even though very few people are still actually shooting on film, frame rate is still an important weapon in any video director’s arsenal.

As you can probably guess, frame rate refers to the number of still frames that are recorded or projected over a period of time. The general measurement used today is fps, frames per second. And while there are definitely exceptions to the rule, for the most part, any video or film that you see today is 24 fps. Why is that, you ask?

History

In the earliest days of silent films, cameras were hand cranked which meant the speed varied from one camera operator to the next. However, the average rate tended to be somewhere in the range of 16 to 24 fps. Once sound was introduced to film, around 1926, those variations in rate could no longer be tolerated because of the effect it would have on the audio. Up to that point, most movie theaters had begun projecting film at 22 to 26 fps, so 24 fps was chosen as the new industry standard as a compromise. And, that’s more or less still the standard today.

Slowing it down

So, if 24 fps is the industry standard, what happens if we really slow that down in the recording process? In the days of silent film, this would be achieved by the camera operator, cranking the camera more slowly than usual. This has the effect of speeding up the action when projected. Here’s a quick example of what undercranking, or slowing down the frame rate, has on scene.

Speeding it up

Let’s get back to those cool slow motion shots we mentioned at the beginning. If slowing down the frame rate, or undercranking, results in a sped up action on screen, it should make sense that speeding up the frame rate should give us a slowed action on screen. Check out this video for a simple example of what overcranking can look like on screen:

Why does it matter?

So, why did I decide to devote a whole blog to this? Well, there’s always the chance that this could help inform any of our clients about some of the jargon they might hear on set. Or perhaps some budding videographer will stumble upon this and get a better understanding of why things are called what they are. But really, I’m writing about this because of some interesting trivia I came across recently.

If I mention the word, Hindenburg, I’m guessing you’ll likely conjure up an image of that terrible disaster. But, if you’re like many people that are even remotely familiar with that incident, you will also think of the reporter’s commentary on the film recorded that day. Herbert Morrison’s voice, a bit high pitched and nasally, exclaiming “Oh, the humanity!” is one of the most iconic moments in film history.

However, it turns out, that for some reason, Herbert’s recorder was undercranking that day which had a very marked effect on the sound of his voice. In reality, Herbert was known for his famously deep voice. So, if we were to accommodate for the recorder’s “slowness” that day, the audio we’d hear would be much different than what I’m guessing we’ve all heard many many times throughout our lives.

Here’s a great clip to illustrate:

Now, this is definitely just the basics. There’s nothing here about interlacing or refresh rates. Let us know if you think a future blog diving into those topics would be of interest.

Jason Cooper