Solution: iPhone Slow-Motion flickering issue

Hi all,

I am a filmmaker experimenting with using my iPhone to make films and have worked with professional cameras of various types from 16mm film to RED. I encountered the slow motion flicker on my iPhone XR recording at 240 fps while playing back on the phone as well as on my iMac (2019) in FCPX. Here is my fix:

The Flicker outdoors/daylight is due to the camera flicking between focus targets and light/exposure settings as you move in and out of light and shade, plus closer or further away from whatever the camera thinks you're focusing on. On a Pro camera I would set white balance, fix a focus target plus aperture, speed and LOCK these before filming. Unless I'm using follow focus, but thats a separate issue. Unfortunately with the iPhone you don't have much control over these.

To reduce or, ideally, eliminate flicker try this:

1._Film in an evenly illuminated area if possible

2._AE/AF LOCK: Focus on what your main subject is and hold your finger down on that spot of the image > a square will appear > keep holding > it will blink > then it will say "AE-AF Lock"

3._ Slide down or up on the thin line next to the square to increase or decrease exposure. TIP: Check your brightest areas aren't blown out.

Before playback on your phone screen make sure to turn off Auto Brightness in Accessibility settings.

To playback in FCPX make sure to use the correct framerate for the timeline.

Good luck and let me know if this fixed the issue for you.

(This Apple video shows you how to get AE/AF Lock.)