When you want to increase the drama of a scene or reveal fine details in a shot, slow motion is a great way to do it. From the iconic use of bullet time in The Matrix, to instant replays in sports, slow motion is a versatile tool for any video producer. In this segment we talk about how it works, proper camera settings for recording, converting your footage for smooth playback, and using it effectively. A well-planned, well-placed slow motion shot can take ordinary footage and make it extraordinary.
When you want to increase the drama of a scene or reveal fine details in a shot, slow motion is a great way to do it. From the iconic use of bullet time in The Matrix, to instant replays in sports, slow motion is a versatile tool for any video producer.
In this segment we talk about how it works, proper camera settings for recording, converting your footage for smooth playback, and using it effectively. A well-planned, well-placed slow motion shot can take ordinary footage and make it extraordinary.
Whether its used to heighten the drama of a scene, or to reveal details in a shot that wouldn’t be noticed in real time, one thing is certain. Things just look cool in slow motion. So, how to do we get that glass smooth footage like we see in the movies? By using proper shooting techniques.
Originally, producing slow motion with film was accomplished by a technique known as overcranking. Essentially, they would record at a rate faster than the playback rate of 24 frames per second..., say, 48 frames per second. When played back at normal speed the result is perfect slow motion. The faster they overcranked, the slower the footage would play back.
If you’re producing a project that will be played back at 24 or 30 frames per second, you can achieve glass smooth slow motion by shooting at a faster frame rate, and then slowing your footage down in post production. Let’s take a look at how this works.
If you capture 60 frames in one second when you record your video and lay those frames along a 24 frame per second timeline, what originally took 1 second in real life, now takes 2.5 seconds to play back. This is essentially slowing down the action to a 40 percent playback rate. Let’s look at an example.
This shot was recorded at 60 frames per second, and we’re playing it back at the same rate, so the motion appears normal. Now let’s jump into premiere to see how we slow it down.
We’ve got our footage imported, and it’s being interpreted as a 60p clip, which is correct. If we place the clip as is on a 24p timeline, premiere will attempt to play it back in real time. To get our clip to play in slow motion, we right click our clip in the project window, select modify, then interpret footage. Now we’ll select the assume this frame rate box, and change the frame rate to 23.976. Now if we add the clip to our 24p timeline, it will play back at 40% of normal speed, and no additional frames will need to be created artificially. Let’s take a look at the footage. Notice that the shot feels much more cinematic and that the fine details of our talent and sparkler are much more apparent.
Choosing to use slow motion can have a huge effect on how the scene feels to your viewers. Let’s take a look at a short scene in real time.
Now let’s take a look at the exact same scene, with all the same cuts, but played back at 40%.
You can see for yourself that simply changing the scene from real time to slow motion creates quite a dramatic difference, literally.
One important thing to note is that while many cameras are capable of shooting 60 frames per second, many of them will not shoot at full 1920x1080 resolution. It’s far more common to find that the 60p frame will record at the reduced resolution of 1280x720.
Another important factor to consider is shutter speed. If you’re shooting 60p, a shutter speed of about 1/120th of a second will give you natural motion blur. Let take a look at an example.
These golf shots were taken with a 1/120th shutter speed. The slow motion definitely shows more detail in the swing, but the blur on the club is a lot more noticeable when it’s slowed down. Let’s freeze this frame to get a better look. The detail of the club is lost in the blur.
Here’s the same shots taken with a 1/500th of a second shutter speed. Increasing the shutter speed has given us far less blur. The detail of the club, and even the grass blades rising and and falling is more apparent. Let’s freeze on the swing to see the difference.
Of course, the faster your shutter speed is, the more you’ll have to open your iris or raise your iso to compensate.
If you’re a plus member, you can watch a full video tutorial on how shutter speed works by clicking on the link.
A 60p frame rate is fairly common, but some cameras can shoot even higher frame rates. The Sony FS700 can shoot up to 960 frames per second, albeit at reduced resolution. To check out sample footage, click on the link in the description.
We got our hands on a GoPro Hero3 Black Edition which can shoot 120 frames at 1280x720. Shooting at 120 frames per second for playback on a 24 frame per second timeline yields glass smooth slow motion that can be played back at 20 percent. This really reveals interesting details in shots that might otherwise be far less impressive. Let’s have a look at some examples.
This ordinary shot of a sprinkler takes on new life when slowed to a 20 percent playback rate, and has a truly cinematic feel to it. It reveals details in the operation of the sprinkler and water droplets that are lost in real time.
Of course, we couldn’t break out the GoPro without the obligatory underwater shot. Notice how the sun rays shimmer so slowly, and the anticipation of the fall is heightened. And of course, the details we can make out as the air bubbles rise back toward the surface looks truly impressive.
Even with a decent stabilizer, it can be tough to get rock steady footage. But planning ahead, and shooting the shot for slow motion playback can help. Let’s take a look at an example.
Here’s our walking shot in real time, and you can see it’s not as smooth as we’d like it to be. Now here’s the same shot played back at 24 frames per second. While it still might not be perfect, it’s certainly an improvement over the original.
Getting that surreal, slow motion footage is the perfect tool for any video producer looking to add drama or enhance the subtle details of a shot. By using these simple techniques, you can incorporate great looking slow motion into your next project. Thanks for watching.