From FaceTime Help:

Choose which camera or microphone to use

If your Mac has multiple cameras and microphones, you can choose which to use for your FaceTime calls.

Open FaceTime for me

• In FaceTime, choose a camera or microphone from the Video menu at the top of your computer screen.If there aren’t any cameras or microphones listed, FaceTime uses the built-in camera and microphone.

Hi,

Have you tried setting the camera to the external Screen one before you close the lid on the Macbook ?

How are the screen set up ?

Which display is FaceTime Set to ? (It may make no difference if you are mirroring)

However with both screen active try dragging FaceTime to the External Display.

I don't have a second display to test this with so these are just ideas.

9:50 PM      Thursday; November 27, 2014

Hi,

I have looked at my com.apple.facetime.plist that holds this sort of info.

(In ~/Library/Preferences)

I only have the one internal FaceTime Camera but it does not show as Default.

The Setting listed is actually blank

The Selected Microphone has 58 and the String.  The default Mic at the bottom also has a String set for the Source.

However the Default Camera has nothing.

If you have Xcode it looks like this  (with your details at the blurry bits)

If you look at your .plist (I used Quick Look  but TextEdit will also open it) you may see both cameras Listed (one as default and one as Selected).

You could try editing the .plist if it shows some info you can transfer to the Default String field.

At this point what you can't tell is if this .plist is informed by others as to the camera and Mic  (there are of course used in Messages and Photo Booth to name two)

7:36 PM      Friday; November 28, 2014

I have the same problem. Did you find a cure for it?

Hi all, same problem also.  Cannot seem to fix it but initial forum in post describes problem accurately.  No Apple Genius bar nearby as I live in Thailand.  Any ideas? 

Thanks

Timothy

Same MBP+ Apple 24 inch Led Cinema display config, and same issue for me (using French for OS language setting):

Each time i launch FaceTime it is set by default to the MBP (Built-in) FaceTime HD cam, so i have to select the Apple Led Cinema Display iSight cam from Video menu and it will work ... until i quit FaceTime, and relaunch it or get a FaceTime call.

Tried to change the default setting in the com.apple.facetime.plist preferences file and relaunch FaceTime app, but prefs file seems overwritten by FaceTime app when launched (with wrong cam default setting again) ...

One more bug eligible for Radar (dunno if this is a system or loc issue for Benoît 's team)?

I have the same problem. I have a MacBook Pro (Running the latest version of Yosemite) attached to an HDTV in my bedroom. The clamshell is closed, so I cannot use the internal iSight camera.

I purchased a Logitech C920 HD Camera (which I have mounted on top of my HDTV), and a Logitech AK5370 Desktop Microphone (which I keep next to my bed on the nightstand), and with the Facetime app open, I can select both the camera I want, and the Microphone I want under the Video menu. However, as soon as I close Facetime, it forgets my preferences, and goes back to the default setting of using the iSight camera (even though the camera is unusable since the MacBook is closed) and it won't even let me answer a Facetime call until I go into the Video menu again, and change the camera BACK to the Logitech camera. I also have to re-select the microphone every time as well.

HI,

The Mic might stay "fixed" if it is the device set in System Preferences > Sound > Input as the choice.

I don't use FaceTime often enough to say if there is a work around.

I have been using Video chat in iChat then Messages  for the most part.

I seem to have read somewhere that you can't or rather FaceTime does not  remember the camera setting.

You are closing the app rather than ending the previous Chat ?

8:47 pm      Thursday; March 12, 2015

Right. I have to close the app, or the camera will stay on.

Ahh,

I forget that since Lion's Add on version of FaceTime you cannot use the camera in FaceTime and another app such as iChat or Messages  (back to the camera only allowing use in one App).

9:08 pm      Thursday; March 12, 2015

Same problem here. Since earlier versions (and now in 10.11.1), I every time have to change cam and mic while it connects with the caller. So annoying.

I have two cams (macbook and external), two mics (macbook and webcam), two sound outputs (display and internal speakers).

There isn't one of those settings that Facetime remembers.

@

Go to Apple icon -> About this Mac -> System report

Select Camera and copy the Exclusive ID for your FaceTime HD Camera.

Then, open ~/Lybrary/Preferences/com.apple.FaceTime.plist in Finder.

If you already have XCode installed, it will open a window like this one below.

Paste the Exclusive ID in Value field for SelectedCamera.

and voilà!