In this video tutorial, we dive into the FPS you’ll typically find in a consumer-priced 4K camera, and what FPS you should use for various subjects.
It wasn’t too long ago that shooting in slow motion was reserved only for cinema cameras. Or, at the very least, high-definition slow motion was reserved for cinema cameras. Then, throughout the 2010s, we started to see more consumer cameras house slow motion. That took a technical reset when 4K reached consumer cameras as, at first, only 24fps was available at 4K. However, as time trickled on, we saw higher frame rates become available to shoot beautiful 4K slow motion. Now in 2021, there are mid-tier priced cameras like the A7S III that can shoot 4K 120fps.
However, what slow motion frame rate should you use for your online content? Too slow and a simple footstep may take five seconds to complete. Too fast and you may not slow down your footage enough.
In the video below, we’ll discuss the FPS you will typically find in a consumer-priced 4K camera, and what FPS to use for various subjects.
As a side note, the equations and language used are based on the principle of using 24 as a standard frame rate, and we’ll only be focusing on the slow motion frame rates found in 4K consumer-priced cameras.
48/50fps
Like the newly released Blackmagic 6K Pro (when filming at the highest 6K resolution), you may have a camera that can only shoot 2x the standard framerate, which may be 48/50fps at 4K. Initially, this may seem like a detriment when other cameras can lean into 60fps and higher. But, the double frame rate is in fact perfectly adequate to capture several elements in slow motion. Because it doubles a single second, it’s not slow enough to become fully evident that slow motion is taking place. Still, contradictory to that, it’s slow enough to emphasize a given component.
For example, as seen in the video tutorial, the waves look as if there’s natural life to its movement. We can see the power of the ocean when it crashes into the shoreline, but it’s slow enough to add more clarity to the element on the screen.
I find 48fps is perfect for instances in time. What I mean by that is scenes where we can softly highlight a moment without it looking like slow motion, but time is prolonged. Perhaps a stranger’s touch, someone thinking, or a valuable item rolling off the edge of a desk. You still need the item’s speed to be visible, but also prolong the moment to cause tension.
60fps
Sixty fps, at least for online content creation, has become the staple entry for slow motion. Given it’s 10-12 frames faster than 48/50fps, meaning it’s 2.5x slower than 24fps, is there really a significant difference?
Well, let’s take a look. If you refer to the tutorial video, we can see an actor walking 24fps towards the camera. It’s a standard, slightly fast pace, but it takes him a solid ten seconds to reach from the start to the endpoint. When we compare a 48fps shot to a 60fps (48 on the left and 60 on the right), we can see it takes three to four seconds longer. In filmmaking, that’s a decent amount of time.
So, 60fps are great for the dramatic character moments. It’s slow enough to be noticeable and put emphasis on the given moment. Whether that’s the hero shot, closing in on an emotional moment, or slowing downtime in an important scene. Essentially, where there’s a human character involved and bringing you into the character’s frame of mind in a human moment.
Additionally (on the technical side), at this speed, it’s slow enough to negate a lot of handheld movement. Then, coupled with a warp stabilizer, you’re going to get a steady handheld movement, but it’s not so slow that it removes the visual language that you’re moving.
120fps
Recently, I was out testing my new camera, and while doing so, a surfer ran in front of me towards the shoreline. I thought, “Nice, this will make for some great B-roll or stock footage.” As the camera can shoot 120fps in 4K, I thought, “I’ll bump it out to the max and hit record.” The outcome, as shown in the video, is way too slow.
120 frames per second, which we see more mid-budget cameras add at 4K, is five times slower than the standard 24fps. Realistically, there’s not an inherent need to use this when filming everyday motion. For example, if we go back to the actor walking towards the camera in the tutorial, it takes nearly three seconds for a single step. So, when would you want to use 120?
Typically, any time something is happening faster than we can humanly see, or at least any subject that becomes obscured with motion blur—like animals running, liquid, or fast-action sports—can benefit from 120fps.
Now, this is not to deter you from 120fps. It’s a fantastic addition to mid-budget cameras. However, if you had to choose between this capability or a camera with built-in NDs, because of the limited practicality of shooting 120fps, I’d often recommend the camera with the built-in NDs.
180fps
Now, as we see 120fps introduced at 4K resolution, we also see even faster frame rates, like 180, introduced at 2K or 1080.
The same principles apply as 120fps, as we’ve moved out of the region of reasonable purpose to film humans at this speed. So, it’ll be useful for elements that have many fast-moving subjects that need to be slowed even further. When we push past 180, we’re moving into special use frame rates typically used for advertising, wildlife, and sports.
In Brief
Let’s break that down.
- 48/50fps for emphasizing small moments to mean something bigger.
- 60fps for character/scene importance and bringing the audience into the bubble of the character.
- 120fps for fast-moving subjects, elements, and sports.
- 180fps will pull from above, but with greater emphasis on slowing things down.
Of course, another aspect we need to consider is the increase in storage space, both on and off camera. If you’re going to be shooting a lot of 120fps footage, a thirty-second shot is actually two and a half minutes. So, it can eat up your media quite quickly.
For more camera tips and advice, check out these articles:
- Low-Budget Tips for Filming Against Blank White Walls
- From Composition to Dehaze: Professional Tips for Filming at the Coast
- Tips for Low-Budget Filming in the Rain
- Documentary Tips for Filming Undercover and Undetected
- Video Tutorial: Learn How to Create Sun Stars with This Quick Tip
Top image via Allison Coles.