Thno wrote: ... Any idea what is causing this?
It may be as simple as your Mac needs to be restarted.
If restart does not fix your problem, you need to troubleshooting to find the cause that must be corrected. The protocol Eric suggested above is a good starting place. If the problem is the same when you test in another user account (don't use the "Guest Account" for this test), the trouble may be a result of conflict with some third party app.
For example, you can test for a Chrome conflict by completely uninstalling Chrome, using OS X Recovery to completely reinstall your Mac OS, and then checking to see if the problem still exists. It the problem continues when Chrome is not installed, some other third party app may be causing the trouble.
Finding which third party app is the problem can be difficult. In worst case, you may need to backup your Mac, completely erase your startup disk, reinstall only Apple software, and verify that the problem is solved. If so, reinstall necessary third party apps one at a time. Test your camera operation thoroughly before the next addition so you can be certain which addition introduces the problem.
Message was edited by: EZ Jim
Mac OSX 10.10.5