Filling up storage space when shooting 4K video with iPhone: Save ProRes directly to SSD

Does your phone's storage fill up when shooting long videos?

You're shooting a long interview, commercial, or cinematic footage for YouTube. Especially in high quality video formats, files can get very large.

Apple recommends ProRes files from HEVC files Up to 30 times larger. On supported iPhone models, it is possible to save the video directly to an external storage unit with a USB-C connection. Apple Support

Step by step usage

1. Prepare a compatible SSD.

Use an external SSD connected via USB-C. According to Apple's documentation, the SSD for recording is exFAT. Password encrypted drives are not supported in this registration workflow.

2. Check the write speed of SSD.

Apple's published requirements are as follows:

• At least 220 MB/s write speed for ProRes 4K 60 fps.
• At least 440 MB/s write speed for ProRes 4K 120 fps.
• The maximum stated power consumption in both cases is 4.5 W.

Check these values from the specifications of the SSD and the connection cable. Apple Support

3. Connect the SSD to the phone with a USB-C cable.

Also take into account the data rate of the connection cable. At high frame rates, an unsuitable cable may cause insufficient recording speed.

4. Enable ProRes.

Settings → Camera → Formats. Apple ProRes.

5. Open the camera app.

Switch to video mode. Select the supported ProRes Log or ProRes HDR option and the resolution and frame rate you want by touching the resolution and frame rate values on the screen.

6. Verify external save destination.

Check that the SSD is connected and the camera app is using external storage before recording starts.

7. Take a short test shot.

Record a few seconds of video first. After checking that the file is written to the SSD and can be played, start the long shot.

Expected result

With the compatible device and SSD, you can save high-quality video files directly to external storage, reducing the need for iPhone's internal storage.

What should you do if it doesn't work?

• If you are getting slow recording warning: Check SSD write speed and cable standard.
• If SSD is not visible: Verify exFAT format and USB-C connection.
• If there is no registration option: Check if your iPhone model and software are supported.
• If there is no 4K 120 fps option: Check Apple's documented model and storage requirements.

Fatal data loss alert

Apple states that for best performance in 4K 120 fps ProRes recording, external storage should be reformatted before each recording session. Formatting may delete existing files on the SSD. Back up your data somewhere else before doing this.

Also, Apple's opened support document lists the iPhone 15 Pro, 16 Pro and 17 Pro models. If you're using a newer model, check the support matrix separately; Do not assume strict compatibility for a device that is not included in the document. Apple Support

Official sources:

• Apple — ProRes video recording and external storage on iPhone
• Apple — Recording to external SSD with Final Cut Camera