Recording in 4k to make a 1080p movie

redman042

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Jun 13, 2008
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Last weekend the airshow was in town, and it was a perfect opportunity for me to test out the 4K video recording mode on my new 6S+. Now, my intention was not to keep any 4K recordings of the event, but instead to edit in 4K in iMovie then export to 1080p. Why would I do this? Mainly for the ability to zoom in post-production without excessive loss of resolution. The result came out pretty great. Check it out (make sure to set the quality to 1080):


I over-used the digital zoom a bit on the first scene and it's a tad blurry, but keep watching. I'm pretty happy with how most of the shots came out.

I'm not sure if any of you have tried to shoot video of an airshow using an iPhone before, but normally you end up with tiny specks in the sky. The distance of the aircraft is a problem with a fixed lens camera. And digital zooming while recording at 1080 degrades the image way too quickly. But by recording in 4K, there are a lot more pixels to work with. It is very easy in iMovie to select a clip and apply a zoom to it. Jump to 3:07 in the video to see a place where I started off without zoom, then split the clip and applied zoom to the second half of the clip where the planes approached each other.

This shooting approach even has an advantage over a proper video camera with a zoom lens. Shooting fast-moving planes while zoomed in is HARD. You very easily lose track of the planes, and everything is shakier. But in 4K, you can keep the camera at a wider angle and not have to track the planes so carefully. Then in post-production, position the zoom just where you need it. Much better.

One other thing that's VERY apparent in this example is how great the Optical Image Stabilization (OIS) on the 6S+ is. I was not using a tripod and I did not apply any software stabilization on the phone or in YouTube. This is straight from shooting to iMovie to rendering.

The OIS performance on this phone is jaw-dropping.

Also, the performance of the 6S+ and iMovie while editing 4K video is equally jaw-dropping. There was essentially no lag at all. While editing 4K! How the heck did Apple manage that in a smartphone?? Pros use uber-expensive desktop rigs to edit footage like this.
 
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Givmeabrek

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Apr 20, 2009
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Terrific! And to think all of the editing was done on the phone it self! Surprised the exposure came out so well. Typically point and shoot cameras will underexpose bright skies. Did you make exposure adjustments when editing? The zooming in post makes all the difference.
 

Bryan Bowler

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Sep 27, 2008
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Great thread redman! And a great example of why shooting in 4K, even with today's standard 1080 playback, can be very beneficial. Nice work!
 
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redman042

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Jun 13, 2008
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Did you make exposure adjustments when editing? The zooming in post makes all the difference.
No manual adjustments while shooting. Given the speed of the action, I had no time to set focus points or slide the exposure adjustment.

Good stuff! Are you digital zooming while recording or during editing?
All during editing. You can select each clip in iMovie, pinch to zoom that clip, then slide your finger around to center the zoom where you want it. One limitation is that the centerpoint of the zoom remains fixed in a given clip.
 

321estrellas

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Sep 28, 2007
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All during editing. You can select each clip in iMovie, pinch to zoom that clip, then slide your finger around to center the zoom where you want it. One limitation is that the centerpoint of the zoom remains fixed in a given clip.
That's awesome. I knew that was one of the advantages of editing 4k. I wonder if you do it during recording if it will have the same effect?
 

redman042

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That's awesome. I knew that was one of the advantages of editing 4k. I wonder if you do it during recording if it will have the same effect?
I think it would, but haven't had time to compare the resulting resolution from each method to see if it's the same. I have also been curious if zooming in while recording in 1080p mode on these new iPhones somehow preserves resolution better by taking advantage of the 4K capability.
 

redman042

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Jun 13, 2008
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Looks great, you prefer this option to be able to zoom, edit over the 60 fps of 1080?
In this shooting situation, definitely. Ability to zoom cleanly is critical for getting enjoyable footage of the planes. If I shot in 1080, the planes would be 4x smaller in the frame.
 
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