I use an iPhone 8 and am going to shoot a short film; which frame rate should I shoot in, 24 fps or 30 fps? (60 fps is an option but that would take up a lot of storage space).
24 (probably really 23.98) is still the standard frame rate for movies while 30 (probably really 29.97) is the standard frame rate for TV in half the world.
24 gives you the "film cadence."
More importantly, your phone probably uses the same bitrate for 24 and 30fps. Since 24fps is 80% of the number of frames as 30 that means each frame of 24 has 1.25 times the available data of a frame at 30, which means better individual frames.
So shoot at 24.
But double check for 24 vs 23.98. That's a real difference.
All I really know about this is the iPhone has a variable frame rate. I know I'll have to use something like Handbrake or OBS to fix this, but with it fix it to 24 frames?
@HeySiri Don't plan on "fixing it" to 24fps. Shoot directly at 24fps. This will require a custom app, as 24fps isn't an option in the built-in frame rates selectable on the iPhone.
One of the first apps I remember hearing about that would let you shoot directly at 24fps is FiLMic Pro. It's got lots of other professional features aside from that, but it's $14.99, and there's no way to try it before you buy it. An alternative that I messed with recently is called ProMovie Recorder. Not as cleanly designed as FiLMic Pro, but you can try all the features before purchasing (it watermarks your videos until you pay), and it only costs $2.99.
EDIT: Just checked the iPhone 8 specs. I have the iPhone 7, and assumed the 8 hadn't added 24fps as an option, but according to the official specs, 4K 24fps is one of the available choices. Oddly enough 24fps isn't a choice for 1080p.
@CleverTagline my phone has a 24 fps option—but I know that phones tend to have a variable frame rate.
@HeySiri See my edit above re: 24fps on the iPhone 8. (I think I was typing my edit while you were typing your comment.)
I think you're getting two topics mixed up. When people talk about variable frame rate, that has to do with the way the video data is encoded. It's not related to changing a device's capture rates between 24, 30, etc.
I'm not familiar with the new features of the iPhone. My last one was a 5s lol. What I do know is that traditionally you should shoot in 24fps (23.976 if you want to be technical), but anymore you don't have to. If you plan on uploading to Youtube or Vimeo 30fps is still just as fine. It doesn't come down to just fps though.
If you shoot 24fps you'll want double the shutter speed so you'd want 24fps at 1/48th or 30fps at 1/60th to get smoother motion. Filmic Pro can do it on the iPhone, but I'm not sure if there is any other program like it that will allow you to do manual control. The slower you push the shutter speed though (say 1/1000th) the sharper the motion. Then there is the consideration of the F-stop... and I think I'll stop right there or I'll be making this reply longer than it should be (sorry... I'm a cinematographer and editor)
@CleverTagline @HeySiri In this case, yes, you want to set your iPhone to 23.97/24, whichever the phone says it is.
That said, yes, it will be variable frame rate and you'll want to transcode. for true 24 Handbrake should be fine. For 23.97...Handbrake will mess it up and you're better off with MPEG Streamclip, FFMPEG or VirtualDub.
Note, I still need to learn FFMPEG and VirtualDub for transcoding for updated tutorial.