External camera does not work on facetime, but the mic does, and the camera works on photobooth.

Hi bertie2017,

Thanks for posting. It looks like you want to know about using a third-party camera with your Mac, and we'd like to see how we can help. It looks like you're able to use the camera in other apps, but not FaceTime. Is that right?

To double-check, are you using these steps? Choose a camera or microphone for FaceTime calls on Mac

"In the FaceTime app  on your Mac, make a selection from the Video menu.

• Choose Use System Setting for your microphone or output device.
• If you select this, FaceTime uses the audio devices set in the Output or Input pane of Sound preferences. For more details, see Change the sound output settings or Change the sound input settings.
• Choose a specific camera, microphone, or output device to use.

If there aren’t any devices listed in the Video menu, FaceTime uses the built-in camera, microphone, and speakers. See Use the built-in camera."

If those are the steps you've tried and you get the same result, try testing in a newly-created administrator account. This will help determine if there's a system-wide issue or if there might be a user-specific cause: Set up users, guests, and groups on Mac. Let us know if the same thing occurs in a new user account, or if the camera is recognized there by FaceTime.

Take care.

Hi there bertie2017,

We appreciate you getting back to us with those results. Since the issue is happening in another user account, and apps other than FaceTime appear to recognize the camera, we recommend using this link to Contact Apple Support to look into this further.

Kindest regards.