Three words sit in Apple’s iPhone comparison rows for iPhone 18 Pro and iPhone 18 Pro Max that most buyers will never use: Apple Log 2, ProRes RAW and Genlock. Genlock is the strangest of the three to find on a phone, because it only makes sense when there is more than one camera pointed at the same thing.
Apple names it and stops. There is no support document, no setting described, no frame rate attached and no accessory listed. What follows is the published side of the line, and then the list of what a camera crew would need to know and cannot yet find out.
What Apple publishes about Genlock
| Key fact | What Apple lists |
|---|---|
| Where it appears | Apple’s iPhone comparison page, video row |
| Models | iPhone 18 Pro and iPhone 18 Pro Max |
| Listed alongside | Apple Log 2 and ProRes RAW |
| Video formats on the same phones | 4K Dolby Vision at 24, 25, 30, 60, 100 or 120 fps |
| ProRes | Up to 4K at 120 fps, with external recording |
| Port available to accessories | USB-C with USB 3, up to 10 Gb/s |
| Setup steps published by Apple | None |
| Accessory or cable named | None |
That is the whole published record. Apple’s press release does not mention the word, and the only context the company gives it is the company of Apple Log 2 and ProRes RAW in a single comparison row.
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What frame sync is for
Genlock is an old broadcast term, short for generator locking. The idea is that several cameras are locked to one shared timing reference so they start each frame at the same instant, instead of drifting apart by fractions of a frame over a long take.
That matters in three situations: multi-camera shoots that cut between angles, live production where a vision mixer switches between feeds, and any setup where two cameras are used as a pair. Without sync, the frames do not line up and the edit has to compensate. Apple does not describe any of those workflows, so treat that as background on the term rather than a claim about how the phone behaves.
Which iPhones list it
| Model | Apple Log 2 | ProRes RAW | Genlock |
|---|---|---|---|
| iPhone 18 Pro | Listed | Listed | Listed |
| iPhone 18 Pro Max | Listed | Listed | Listed |
| iPhone 17 Pro | Listed | Listed | Listed |
| iPhone Duo | Not listed | Not listed | Not listed |
| iPhone 17 | Not listed | Not listed | Not listed |
| iPhone Air | Not listed | Not listed | Not listed |
The split is worth noting for anyone weighing up Apple’s two flagship iPhones this autumn. The $1,999 iPhone Duo records 4K Dolby Vision up to 120 fps and adds Dual Capture at 4K 30, but Apple lists none of these three professional items for it. On video formats alone, the cheaper Pro is the better documented phone, which is also the shape of the Duo against Pro Max comparison.
The questions a crew would ask first
- How the reference reaches the phone. Apple names no cable, adapter, app or wireless method.
- Whether timecode travels with it, which is a separate thing from frame sync and is not mentioned.
- Which frame rates are supported. The video row lists six, and Genlock is attached to none of them.
- Whether it works alongside ProRes, ProRes RAW, Apple Log 2 or Cinematic mode, which tops out at 4K Dolby Vision 60 fps.
- Whether it needs a third-party app, and whether any exist at launch.
- Whether the 10 Gb/s USB-C port is involved at all, given external recording uses it.
What Apple has not said
Apple has published no support article, no developer note in its consumer pages and no price for any hardware that would feed a reference signal to an iPhone. It has not said whether Genlock is available on day one or arrives in a later release of iOS 27, and it has not said whether the feature is limited to the 24 mm main camera or works across the three rear lenses.
Pre-orders open at 5 a.m. PT on Saturday, September 12, iOS 27 is free on Monday, September 14, and iPhone 18 Pro reaches stores on Friday, September 18. Until then, Genlock on an iPhone is one word in a table.
