One minute of iPhone ProRes is about 6 GB. Here is where it goes on your Mac

Pro iPhones can shoot ProRes video and ProRAW photos. Both keep far more image data than normal, which is great for editing and heavy on storage. A short family clip shot in ProRes by accident can be several GB.

How big they are

Those are Apple's own approximations. ProRes is roughly thirty times the size of normal 4K video.

Find them on your Mac

# Large video files anywhere in your home, over 2 GB
find ~ -type f \( -iname '*.mov' -o -iname '*.mp4' \) -size +2G 2>/dev/null

# ProRAW photos are DNG files
find ~/Pictures ~/Downloads ~/Desktop -iname '*.dng' 2>/dev/null | wc -l

Inside the Photos library they are there too, just not visible by name. In Photos, Media Types in the sidebar lists RAW photos, and you can sort by size using View, Sort By in some versions.

Keep them only while you edit

1. Import ProRes clips to a folder on an external SSD, not into Photos.
2. Edit from the drive. See the iMovie library or Final Cut libraries.
3. Export the finished film in HEVC, which is a fraction of the size.
4. Archive or delete the ProRes originals.

Stop shooting it by accident

On the iPhone, Settings, Camera, Formats. Turn off Apple ProRes and Apple ProRAW if you do not edit professionally. When they are on, the camera shows a ProRes or RAW toggle; check it is off before filming birthdays.

Video storage in general: 4K video storage per minute and Mac storage for video editors.