I was running a few tests with the Pi camera when I dropped it, now the cable is just the right length so that the back of the camera hits the GPIO pins. With that the camera would no longer work and every time I tried to connect it I got the following error report:
received unexpected camera control callback event 0x4f525245
When I Googled this error I found it was a fairly common problem and that it meant the camera was dead. I tried a new camera but that also gave the same error. At this point I began to suspect I had corrupted the operating system, so I built a new Raspian SD card, but the camera still would not work.
When I tried both cameras on another Raspberry Pi they both worked, so I had not fried the camera but the Raspberry Pi instead. The camera is cheaper than the Pi so in some ways I would have preferred it to have been the camera that had died. At least the Pi retains some functionality, it just will not operate a camera.
The moral of this tale is that it is necessary to take the greatest care when handling that tiny camera and that sometimes the Internet may not have the right answer.