This procedure may show which program is using the camera. It makes no changes, and therefore will not, in itself, solve your problem.
Please triple-click anywhere in the line below on this page to select it:
sudo lsof -Fc +D /L*/Cor*/*/*/AppleCamera.plugin | sed '2!d' | cut -c2- | pbcopy
Copy the selected text to the Clipboard by pressing the key combination command-C.
Launch the built-in Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window by pressing the key combination command-V. I've tested these instructions only with the Safari web browser. If you use another browser, you may have to press the return key after pasting. You'll be prompted for your login password. Nothing will be displayed when you type it. If you don’t have a login password, you’ll need to set one before you can run the command. You may get a one-time warning to be careful. Confirm. You don't need to post the warning.
If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator. Log in as one and start over.
Wait for a new line ending in a dollar sign ($) to appear below what you entered.
The output of the command will be automatically copied to the Clipboard. If the command produced no output, the Clipboard will be empty. Paste into a reply to this message.
The Terminal window doesn't show the output. Please don't copy anything from there.
