Buying an SSD for iPhone video? Choose the app and format first

Ordinary long video: check HEVC first

If you need watchable footage rather than a professional post-production format, investigate the app’s HEVC option before buying a larger drive.

Apple’s Final Cut Camera format guide lists HEVC alongside several ProRes choices and explains that HEVC creates comparatively small files. Available modes depend on the device and other settings. The app also displays an estimate of recording time as settings change. Final Cut Camera format controls.

That gives you a useful question to answer: can your chosen phone and current app version record your required resolution, frame rate and codec to the destination you want?

Do not stop at “the app supports HEVC” or “the app supports an SSD.” Confirm both together in the actual recording setup. A format that appears in an app’s overall guide may be unavailable in a particular device or mode.

ProRes in Apple’s Camera app has its own requirements

Apple documents external ProRes recording on iPhone 15–17 Pro models using an exFAT drive and a USB 3 cable rated for at least 10 Gbit/s. Its listed minimum write speeds are 220 MB/s for 4K60 and 440 MB/s for 4K120; the latter is listed for iPhone 16 and 17 Pro models. The corresponding drive power limit is 4.5 W. Password-encrypted drives are not supported for this path. Apple’s ProRes requirements.

These are requirements for that documented workflow. They are not a blanket specification for every external-recording app.

If ProRes is not part of your editing plan, do not select it simply because plugging in a drive makes it available. You could create a storage problem that a different recording format avoids.

Keep Final Cut Camera’s cable rules separate

Apple’s Final Cut Camera 2.4 recording guide specifies an external exFAT SSD and a supported iPhone. It permits a USB 3.1 Gen 1 cable rated for 5 Gbit/s or better for ProRes 4K60 and lower frame-size/frame-rate formats, while listing 10 Gbit/s for ProRes 4K120. The recording destination appears at the top of the screen. Final Cut Camera recording instructions.

A cable that charges the phone is not thereby proven suitable for recording. Read its data specification and follow the requirements of the app you will actually use.

A 10 Gbit/s cable may simplify a basket intended for both documented paths, but the cable alone cannot validate the drive’s write performance, power needs or a mode your phone does not offer.

Estimate capacity with your own sample

Record a representative five-minute clip using the exact settings you intend to keep. Note its file size and calculate storage per minute. Use footage similar to the real event rather than assuming every scene compresses identically.

Here is a hypothetical example, not a measured iPhone result:

• Five-minute sample: 1.5 GB
• Estimated rate: 1.5 ÷ 5 = 0.3 GB per minute
• Planned recording: 180 minutes
• Estimated footage: 180 × 0.3 = 54 GB
• Chosen planning allowance: 25%, giving 67.5 GB

The 25% allowance is an example budgeting choice, not Apple’s requirement or a guarantee. Compare the estimate with actual free space shown on the destination, after allowing for footage already stored there.

Repeat the sample if you change codec, resolution or frame rate. For variable file sizes, try several representative clips and use a cautious planning figure. The app’s remaining-time display is a useful second check.

In this example, buying a much larger drive solely because “three hours means huge files” would be premature. Format and actual sample size have changed the capacity question.

Check the complete physical setup

Put four items in the basket: the drive, a suitable data cable, any necessary mounting arrangement, and a documented power solution if the setup requires one.

Keep cable strain away from the phone’s socket. Check that a proposed mount fits the phone case, leaves the controls accessible and does not interfere with your tripod or grip.

Read the SSD specification carefully. An advertised peak read speed is not evidence that the drive sustains the required recording write rate. Capacity also says nothing about that performance.

Before an important event, make and review a longer test recording with the intended setup. Watch for interruptions, confirm the file opens, and check that it was actually written to the external destination. A successful short clip cannot establish full-event reliability.

Protect existing footage before changing the drive

Formatting erases the drive. Back up its contents elsewhere and verify the backup before considering a format change. Do not format the only copy of footage you need.

Apple additionally calls for reformatting before each native Camera 4K120 ProRes session. That requirement makes a separate, verified backup especially important; it is not a reason to erase first and sort out files later. Apple’s recording guidance.

Stop recording before disconnecting the drive. Keep another verified copy of important recordings rather than treating the recording SSD as the backup of itself.

When you can skip the purchase

If your preferred format fits the phone’s available storage for the planned event, record internally and transfer afterward. If your job is only archiving existing footage, solve that transfer-and-backup problem without paying for an unneeded camera rig.

Buy when the app, device, mode, capacity estimate and complete connection are all clear. Ask the manufacturer when sustained writing or power requirements remain unknown. More terabytes should be the last decision, after you know what you are asking them to hold.