4 Common Reasons to Convert Frame Rate in Films
The frame rate of a film determines how fast or slow it will play back. Film plays back at a rate of 24 frames per a second (fps). When film was recorded at a frame rate less than that, say 12 fps for example, then it would appear to be playing back in high speed. If the frame rate was greater than 24 fps when recording, then it would play back in slow motion. Here are 4 common reasons for converting the frame rate in films.
1. To Show the Passage of Time
Time lapse is a visually interesting technique to show the passage of time. It's done by mounting a camera in a fixed position and having it record for a while. It can either take a single picture every few minutes, or you could record a few hours worth of footage and compress it down later in editing. Although that isn't the proper way to do time lapse, it creates the same effect, at the sacrifice of a lot of hard drive space (but sometimes that's your only choice if you don't have the right tools for the effect).
A common time lapse example is having a a shot of the sun rising to transition from night to day. While it may take a couple of hours for the sun to rise over the horizon and shine over the hills, you can compress the action into a few seconds with time lapse.
2. To Exaggerate a Character's Speed
You can use fast speed to make a character appear like he is moving faster than he really is. For example, you can demonstrate how hyperactive a character is after drinking a case of red bull by having him move at high speeds to exaggerate the effects of energy drinks.
3. To Make It Visually Appealing
There was a Chapelle Show skit a few years ago called 'Better in Slow Motion'. It played with the concept that everything looks cooler in slow motion. He would show mundane and boring activities in normal play back, and then play them again in slow motion to show how much cooler they looked.
One example was going to the club. Music videos make going to the club look so cool because everything is in slow motion. Of course in reality, it's usually not cool because there are too many people and a lot of other problems as well. In the skit, he's trying to push his way past people as he makes his way through. At normal playback speed it looks awful, but in slow motion it looks cool.
4. To Draw out Tension
Action movies use slow motion to draw out tension which keeps audiences at the edge of their seats. You're craving to see how everything is going to turn out and the slight slow motion raises your tension up just a bit.