Thank you Barney-15E, leroydouglas, and QuickTimeKirk.
Barney, I don't use FaceTime or Photo Booth, not even on my iPhone 8. The only apps I frequently open are Firefox, Pages, Numbers, Mail, Messages, and Stickies. I'm a new user of Mac, switching over last fall after 25 years of Windows.
QuickTimeKirk, I used black electrical tape over the lens on my Windows laptop, but thought I might try disabling the camera on the Mac. Guess I'll use the tape again.
leroydouglas, thanks for your reply. I'm hesitant to attempt a reboot as everything else is humming along, not like the constant struggle I had with Windows.