Can you use the Action Button to start a dual camera recording on iPhone?
Partly. The Action Button can take you from the Lock Screen straight into DualCam in one press, which is a real time saver. What it cannot do is skip past that and drop you directly into a running recording, because that would need the app itself to offer a dedicated action for the button to trigger, and DualCam does not have one.
The rest of this is about where that line actually sits, and what closes the remaining gap for someone trying to start filming as fast as possible.
What the Action Button can trigger, generically
The Action Button, on the iPhones that have one, is a system-level control configured in Settings, not something any individual app can add itself to. Apple ships a fixed menu of things it can be set to do — silent mode, a Focus, the camera, the flashlight, a voice memo, the magnifier, an accessibility shortcut, and opening a specific app among them. A third-party app only shows up in that list as something the button can launch; it does not get to define its own custom entry unless it publishes its own action through Shortcuts.
That last part is the one that matters here. Apple's Shortcuts app lets a developer expose specific, named actions — "start recording", say — that then become things a user can point a Shortcut, an automation, or the Action Button at. Whether that exists for a given app is entirely up to whether the app built it.
Opening DualCam is real; jumping into a recording is not
Setting the Action Button to Shortcut → Open App → DualCam works exactly like tapping the app icon, just reachable in one press from the Lock Screen instead of a swipe and a tap. That is a genuine, useful shortcut for anyone who reaches for a dual-camera shot on short notice.
What is not on the table is a button press that goes further than that — one that opens the app and also starts the file rolling in the same motion. DualCam does not publish a Shortcuts action for starting a recording, so there is nothing for the Action Button, an automation, or a Shortcut of your own to call. "Open the app" is the ceiling, not a limitation of the button itself but of what the app on the other end of it is offering.
Even a direct binding would not be instant
Worth knowing before wishing for a faster button: getting straight to a rolling recording from a cold start was never going to be one instant motion, regardless of what triggered it. A multi-camera session has to configure two camera inputs against one shared hardware budget before either camera produces a usable frame — working out which formats qualify, whether the combination fits, and what to fall back to if it does not — and that negotiation happens before the session starts producing frames, not while it is already running. It is the reason a dual-camera camera screen shows a brief loading moment even when opened normally, covered in more detail in the guide on why dual recording takes a moment to start.
A button that skipped the app-open step would still be waiting on that same configuration work underneath. It would save the swipe and the tap, not the setup.
What actually shortens the gap
- Bind the Action Button (or Back Tap, on an iPhone without one) to Open App → DualCam. It is the fastest real path from a locked phone to the camera screen.
- Set the countdown timer — off, 3, 5 or 10 seconds — before a take you know is coming. It has to be set before recording starts, but once it is, it absorbs the remaining setup pause instead of you standing there watching a loading preview.
- For several short takes back to back, stay on the camera screen between them rather than backing out to the Home Screen and relaunching. Reopening the app is what throws away the configuration work the session already did; leaving it open keeps both cameras already running.
Common follow-up questions
Can I set the Action Button to open DualCam?
Yes. Choose Shortcut in the Action Button settings, then Open App, then DualCam. It behaves exactly like tapping the icon, just reachable in one press from the Lock Screen.
Can I set the Action Button to start recording directly, without opening the app first?
No. That would need DualCam to publish a dedicated action through Shortcuts, and it does not have one. The button can only launch the app, the same as any third-party app without its own Shortcuts action.
If DualCam did offer that, would recording start the instant I pressed the button?
Not quite instantly. A multi-camera session has to configure both cameras against a shared hardware budget before either produces a frame, and that setup cost exists regardless of what triggers the app to open — a button press would remove the swipe and the tap, not the configuration itself.
Want to just do this?
DualCam records the iPhone front and back cameras at the same time and writes one finished MP4 while you shoot. Free, no account, no ads, nothing leaves the phone.