My first full time job after high school was in the field of Camera Repair (See my Work History). Prior to this I had taken a correspondence course in camera repair while I was in High School. (See the Education Section) I did real well with this job, and my bosses liked my work. All the guys in the shop used to call me "wunderkind" because most of them were from Eastern Europe. When I started to work in this field, cameras started to incorporate more and more electronic components. These components were really added on subsystems devoted to the cameras through the lens light metering function. Back then, for most cameras you moved the shutter speed dial or diaphragm ring to center a pointer in the viewfinder and then take the shot. The more complex auto exposure cameras like the Konica brand SLRs used a complex system of internal cams and levers, which mechanically trapped the needle pointer to control the amount that the lens diaphragm would close down as the shot was being taken. This type of Auto Exposure was called Shutter Priority, because the aperture or F Stop was varied while the shutter speed is held constant.
Other cameras had similar systems, but to vary the shutter speeds instead. These were called Aperture Priority Auto Exposure Cameras because the F-Stop was held constant while the shutter speed was varied.
The bottom line is that underneath all of the electronic systems there existed the core mechanical camera. Back then if your internal light meter broke down then you could use an external light meter and set the cameras shutter speed and diaphragm to get the shots you wanted.
I started to take courses in electronics to increase my ability to understand and repair these light-metering systems. Then in the late 1970s along came the Cannon AE-1. (Auto Exposure - 1) This camera did not have the usual plethora of intertwined precision mechanical parts. This is the camera that told me it was now time to exit the camera repair field because skilled craftsman will no longer be needed in the future as they become supplanted by cheap throw away technology that is not really repairable anyway. Let me explain.
In the photo above you can see that on the inside the Cannon AE-1 was wrapped in a flexible circuit board. At certain points on this board were soldered ASICs. These are (Application Specific Integrated Circuits) in other words the board had IC chips designed to perform a specific function. There was an IC for the light metering and another one for exposure control to handle the movement of the diaphragm and the shutter speeds. Both the diaphragm and shutter were controlled by electromagnets. The only subassemblies that were still mechanical in nature were the film transport, mirror lift mechanism, and diaphragm stop down linkage. Now with today's digital cameras all of these mechanical systems have been eliminated.
I did add a mirror lock up function to the Canon AE-1 you see above, but this is a feature needed only in rare cases so it had no real market value. I did exit the camera repair business, but the farthest I could travel at the time was into the motion picture camera business. Check out that section to see what I did there.