Can iPhone 15 record ProRes to a USB-C key?

Ensure Device Compatibility:

Use an external storage device that supports write speeds of at least 220 MB/s and has a maximum power draw of 4.5W. The device should be formatted in exFAT or APFS. ​

Enable ProRes Recording:

Open the Settings app.​

Scroll down and tap Camera.​

Tap Formats.​

Under Video Capture, toggle on Apple ProRes. ​

Connect the External Storage:

Use a compatible USB-C cable to connect your external storage device directly to your iPhone's USB-C port.​

Set Up the Camera App:

Open the Camera app.​

Swipe to select Video mode.​

Tap the ProRes button (it may appear as a crossed-out "ProRes" initially) to enable ProRes recording.​Adjust the resolution and frame rate by tapping the settings in the top-right corner (e.g., 4K at 60 fps). ​

Start Recording:

With ProRes enabled and the external storage connected, tap the Record button to begin recording. The video will be saved directly to the external storage device.​

Note: Recording ProRes video at 4K 60 fps requires an external storage device due to the large file sizes. ​

According to About Apple ProRes on iPhone - Apple Support you need a Pro model to record video in Apple ProRes. It also gives instructions for recording directly to external storage.