Your Mac keeps picking the wrong camera

You join the call two minutes late, and the first thing anyone says back is not hello. It's "we can see your phone." Nobody touched a setting. Somewhere between opening the lid and clicking Join, an iPhone on the desk offered itself as the camera, and Zoom took it without asking. Now the room is looking at a phone propped against a monitor stand, and you're fixing it out loud while the meeting keeps moving.

Camera selection on a Mac happens inside each app, not through one system wide switch, which is why Zoom can be pointed at your webcam while Teams reaches for the nearest iPhone through Continuity Camera. You can turn Continuity Camera off for a specific iPhone from that iPhone's own settings, which stops it offering itself to any app at all. Neither fix guarantees the next app you open gets it right, since each app keeps its own memory of what you picked last. The only check that holds up is looking at the picture before you join. A correct name in a dropdown can sit above a feed that isn't.

Taperlark makes Preen. This post names other apps, including free ones. Prices and version numbers were checked on the date shown and link to each developer's own page. If we got something wrong about your app, email support@taperlark.com and we will fix it and say what changed.

I build Preen. Nothing here is a benchmark: this post contains no measurements, and where a number appears it comes from the app's own code, from a vendor's published page, or from Apple's documentation, and it says which. Product behavior described here is Preen's current shipped build. Facts about other apps were checked on 23 July 2026.

This is one entry in a longer series on the Preen blog about the thirty seconds before a call actually starts.

Why there is no single setting for this

macOS has no system wide camera picker

System Settings has no default-browser-style pane where you choose once and every app follows it. Apple's permission system, under Privacy & Security > Camera, decides which apps may ask for a camera at all, but permission and selection are different questions, and macOS only answers the first one centrally. Once an app has permission, it enumerates cameras through its own AVCaptureDevice.DiscoverySession call, and keeps a private record of what you picked last. Preen's own single camera entitlement works the same way. No exceptions. It owns exactly one AVCaptureSession, invisible to Zoom, to Teams, or to anything else running alongside it. Every camera app on your Mac is its own island, ours included.

What Continuity Camera is doing when it takes over

Apple's Mac User Guide describes the underlying rule plainly: the camera turns on by itself the moment you open an app, or use a feature, that can use it, naming FaceTime and Photo Booth as the ordinary examples (Apple Support, macOS Tahoe 26 guide, accessed 23 July 2026). Continuity Camera works by adding your iPhone to that same list of enumerable devices, one of four device types Preen itself asks for: built in, external, continuity, and Desk View. Once your phone is unlocked and close enough, it becomes just another row in that list. An app that defaults to the first result, or whichever camera it last remembers, can land on the phone instead of the webcam without anyone approving anything. Nobody asked. It's what happens when four kinds of camera get folded into one undifferentiated list.

How to stop a specific iPhone offering itself

You can remove one iPhone from every app's list at once, from either end of the pairing. On the iPhone, the switch lives under Settings, General, AirPlay and Handoff. On the Mac, it's under System Settings, General, AirDrop and Handoff, with each paired iPhone listed and a switch of its own. Turning it off removes that phone from the list every app enumerates, not just the one you were looking at. It won't fix everything, though. If your own webcam loses out to the built in camera, that's an ordering issue inside one app, and no global switch reaches that far.

Where the picker lives, app by app

Zoom

Zoom keeps its camera choice under Settings > Video, and again as a small caret beside the camera icon on the in call toolbar. The dropdown lists every device Zoom's capture session enumerates, labelled however the driver named it, so "iPhone Camera" and a webcam's own model name sit in one flat list with nothing grouping them by kind. A label naming the camera you want does not prove that camera is the one feeding the preview beneath it at that instant. Reopen the video settings pane after switching, rather than trusting the highlighted row, and read the preview square instead.

Microsoft Teams

Teams puts the same choice one level deeper, inside the Device settings panel, reached from the meeting's three dot menu, or from the app's own settings beforehand. It shows a live thumbnail beside its dropdown, more than some apps bother with. Teams does not document how or when that thumbnail updates, so treat it the same way as any other picker: reopen the panel right before you go live rather than trusting a thumbnail from earlier in the setup.

Google Meet, and why the browser matters

Meet has no device menu of its own, because it runs inside whichever browser you opened it in, and its camera list is built from that browser's own permission grant. Click the camera icon in the address bar, or the three dot menu inside the call, and the list comes from the browser's getUserMedia call, not from anything Google wrote. This is where the browser matters more than the meeting app: Safari and Chrome each hold a separate camera authorization from macOS, granted independently under Privacy & Security > Camera, so the same Mac can show Safari one default and Chrome a different one entirely.

Slack

Slack's camera control sits inside a huddle, in a small icon at the bottom of the huddle window, and there's no settings pane for it outside of a live one. You cannot check or change the camera until you've already joined, so there is no way to confirm which camera Slack picked before you are already on the tile. Glance at your own tile the moment you join, rather than assuming the newest camera won.

FaceTime

FaceTime keeps its camera choice in the menu bar, under the Video menu, available once a call is active and the app already has camera permission. That same menu carries Apple's Center Stage, Portrait and Studio Light effects, so camera selection and cosmetic processing sit together. Apple's own instructions for those effects begin the same way every time: go to an app that captures video, such as FaceTime, then click the Video icon in the menu bar (Apple Support, accessed 23 July 2026). What the menu won't tell you is whether an active effect is masking a wrong camera, since Center Stage or Studio Light can make almost any feed look intentional. Turn effects off before deciding which one is the actual problem.

Safari and Chrome, for everything else

Every other site that wants your camera, from a webcam test page to a video client with no native Mac app, goes through Privacy & Security > Camera at the OS level first, then a second, per site permission the browser tracks on its own. That second grant is why a page can work in one browser and sit stuck on a prompt in the other, and why revoking a site's access in Chrome does nothing to what Safari remembers about the same page. Check the camera icon in the address bar; it shows the live, per site grant, not just whether the browser may ask at all.

The step everyone skips

Confirm the feed, not the setting

Every picker above answers a slightly wrong question. It tells you the choice. It does not tell you what the camera is showing right now, and those are different facts. A dropdown can read "FaceTime HD Camera" while the frame behind it is frozen, black, or coming from a device that disconnected before the label caught up. The only test that closes that gap is opening a live preview and looking at it, the whole reason a menu bar preview app like Preen exists instead of nothing. Preen holds one capture session open in a floating window that stays visible while you switch to your meeting app, so you watch the picture change the moment you pick a camera. Its own popover is not the full picture, though: it crops your feed into a fixed frame by scaling to fill rather than shrinking the whole image down, so the top and bottom of a widescreen feed get cut off there specifically. Use the floating window when framing matters.

What "camera in use by another application" actually means

Apple documents the mechanism behind that message directly. A green light beside the camera glows to show it's on, and it turns off only when you close or quit every app or feature that can use it (Apple Support, accessed 23 July 2026). "Camera in use by another application" is the same rule seen from the other side. Some other process still holds a session against that device, not necessarily one with a visible window, and macOS enforces exclusivity on the hardware rather than letting two apps share a feed. There is no sharing. If that session is still running, the next app in line gets nothing.

When one app holds the camera and the next one gets nothing

This is also the honest limit of what a small preview app can do for you, and six different ways to check a camera before a call run into the identical wall. Preen cannot free a camera another app is holding, because nothing in a normal capture session carries the authority to end someone else's; there is no lockForConfiguration call, no exclusive access API, anywhere in the code that would let it try. There shouldn't be one. An app that could evict another app's camera session could evict yours too. What Preen can do is tell you plainly the camera is unavailable, so you close the culprit rather than restart your Mac out of habit, usually by quitting recently opened video apps one at a time until the camera indicator goes out.

I don't know why some external webcams stop reoffering themselves after a hub sleeps and wakes back up. I haven't found the pattern, and I'd rather tell you it happens than pretend I've solved it.

Free ways to look at your camera first

If all you need is confirmation that a camera works before a call, you don't need to buy anything. Apple lists Photo Booth, FaceTime and QuickTime Player among the Built-in Apps on its current Mac technical specifications pages, included at no separate charge (Apple, Mac technical specifications, accessed 23 July 2026). Photo Booth and FaceTime trigger the camera the instant you open them, and QuickTime Player gives a live feed under File > New Movie Recording without starting a recording, the closest built in option to a dedicated preview tool.

A few dedicated apps sit between free and the price of a coffee. Apple's US Mac App Store lists Cam Dot, by Maria Hollweck, at US$2.99 with no in-app purchases and states it requires macOS 13.0 or later, and the same store also sells Cam Dot inside the developer's ten app Good Bar Complete bundle at US$9.99; the developer's own feature list covers a preview, mirror mode and camera switching, active only while the popover is open, with no mention of snapshot capture or microphone control (Cam Dot Mac App Store listing, checked 23 July 2026). Rafael Conde lists Hand Mirror as a free download on the US Mac App Store, with the core preview at no cost and the Plus features unlocked by a one time purchase starting at $6.99, and the listing states it requires macOS 14.4 or later (Hand Mirror Mac App Store listing, checked 23 July 2026). Sindre Sorhus prices Camera Preview at $6.00 on the US Mac App Store, a one time purchase at version 1.8.1 as of 23 July 2026 that requires macOS 26.0 or later, a floor well ahead of the other two apps here, and his FAQ states that recording and filters are outside the scope of the app while describing a window size the app remembers between launches (Camera Preview Mac App Store listing and vendor FAQ, checked 23 July 2026).

If a mirror and a way to switch cameras is the entire job, one of those three already does it. You're done.

Questions people ask

How do I stop my iPhone being used as a webcam on my Mac?

Turn it off from either device: on the iPhone under Settings, General, AirPlay and Handoff; on the Mac under System Settings, General, AirDrop and Handoff, listed per paired iPhone. Either removes that phone from every app's camera list at once.

Why does Zoom show my external webcam but Teams does not?

Each app enumerates cameras on its own schedule and caches the result. If Teams built its list before the webcam was plugged in, it won't see the new device until you reopen its settings panel, even though Zoom, opened afterward, sees it right away.

Is there one setting that changes the camera for every app?

No. Turning off Continuity Camera for a phone removes it from every app's list, the closest thing macOS offers to a global switch, but that only removes a device. It cannot set a preferred camera for every app, since each app stores that preference on its own.

Why does my webcam show a black screen in one app but work in another?

Most often another app still holds an active session against that camera, and macOS will not let two apps share the hardware, so the second app gets a black frame instead of a shared feed. It can also mean the app cached its camera list before that device was ready to answer.

Does the green light mean the right camera is on?

It means a camera is on. Not which one. Apple's own description of the indicator covers only whether the camera is active, not which device is behind it, so the light glows the same way whether your Mac is using the built in lens or an iPhone across the room.

My camera picker only lists one camera. What now?

Check that the missing camera has been granted permission at all, under Privacy & Security > Camera, since a device with no permission never appears in another app's enumeration. If permission looks right, unplug and replug the camera, or toggle Continuity Camera off and back on, so the app is forced to rebuild its device list from scratch.

Look at the preview before you join, not just the label.

Preen keeps that same check one click away in the menu bar, so it takes a few seconds instead of a scramble after everyone's already looking at you.