How to use iPhone 4K video to provide operator-free pan and zoom

The iPhone's native 4K recording capability can be incredibly useful as a video production tool. The higher resolution creates what is essentially a virtual camera lens that can be dynamically moved and aimed after the video has been shot. To learn how, watch this video.

When I bought my iPhone 6s Plus last autumn, one feature I never expected to use was the phone's 4K video recording capability. I didn't have a 4K TV, I didn't expect or plan to be watching 4K videos, and I frankly considered it a novelty.

I was wrong. When I started to record videos for DIY-IT's 3D Printing Discovery Series, I discovered just how incredibly useful 4K video can be. The trick isn't using the super high-resolution so you can see the pores of actors' faces in even more detail, it's how 4K video provides operator-free pan and zoom.

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In this article, I'll show you why that's such a useful tool, and get you started on the way to doing it yourself.

Here's how I came upon this capability. When I started the 3D printing series, it became clear that I was going to be doing build videos that take readers and viewers through the process of discovering what can be done with 3D printing and learning how to do it.

Those videos require an interesting combination of shots, from the usual talking head shots to close-in zooms of parts being made, to the assembly and finishing process. In my case, I'm doing most of the work in our garage. I have two long workbenches (you'll see them in the video for this article), and very good lighting, so the space lent itself perfectly to the project.

The downside was these projects take a long time, and I wanted to record as I was working on them. While I could talk my wife into coming into the garage and pointing the camera at me for five or ten minutes, making her stand around for a few hours per work session was just not going to happen. Not only would it be tedious for her, but she's got her own set of responsibilities that keep her busy, too.

The iPhone's 4K video capability

That's when I thought about my iPhone. Not only does it have 4K video, but it has 128GB of storage (which comes in very handy when you're recording 4K videos, believe me).

A 4K video is 3840x2160 pixels, compared with 1920x1080 for 1080p, or even 720p, which is 1280x720 pixels. HD YouTube videos are generally either 1080p or 720p, so a 4K video would effectively allow a 4x to 8x digital zoom, while maintaining really good fidelity.

In a normal video shoot, the camera can be handheld, mounted on a tripod, or even on a track. As the subject moves, an operator pans the camera to track the movement of the subject or zooms in to capture more detail.

David's workshop through the iPhone's lens

While there are some devices that automatically track movement and move the camera alongside, they're not cheap and they add to the overall system complexity, without necessarily providing the really good pan and zoom you'd expect from a human operator.

Using ScreenFlow

Instead, I decided to see if the program I use to record my screencasts would work with 4K video. I use a well-respected screencast program for the Mac called ScreenFlow. It's about a hundred bucks, and worth it.

In a screencast, you often want to zoom in and out on a detail, say a menu item to be clicked or an option to be set. ScreenFlow provides the ability to set those zoom and move points, along with a lot of other features. Normally, you'd use it to record the screen (which I did in the video included in this article), but it also allows you to import media assets and do the same with them.

While the features page for ScreenFlow didn't say it supported 4K, I decided to give it a try -- and it worked. In fact, it worked amazingly well. It's also very easy to get started with. As the video demo I've included with this article shows, you really only need to learn a few basic features to get up and running.

More benefits

There's one more benefit to using something like ScreenFlow to do operator-free pan and zoom: you can virtually retake a scene. With a physical camera, when you zoom in or pan to something, if you don't get that movement perfectly right at the time of recording, you're stuck. That's all the data that's in the media file.

But with a 4K video media asset, you often have a ton of surrounding video, and so you can dynamically refocus and move the virtual camera lens to a different location.

In essence, your video (especially for things like training videos and tutorials) are no longer nearly as dependent on the operator's skill as they used to be. In fact, you can produce excellent videos just by setting the camera up and pointing it in the right direction.

So go ahead and give it a try. It's a lot more fun and empowering than I expected, and it's turned out to be a very useful go-to tool that I use every week.
