flavio81
Member
The same time the AE-1 is very susceptible to sand...
All electronic cameras are mechanical as well. But electronics allow for reducing mechanical parts and, as long as the electronics are reliable, this should increase the reliability of the system.
For example the Canon EF has all sorts of contraptions to achieve shutter-priority AE:
- The galvanometer body rotates according to the shutter speed dial via a pulley and string
- Said string is also "altered" using a planetary gear system that varies said rotation to compensate for the selected ISO
- Upon pressing the shutter release, a "trapped needle" system traps the galvanometer needle so the diaphragm operating lever on the lens "descends" to the proper f/stop. This requires many mechanical parts.
Now, a camera like the AE-1 is also able to achieve shutter-priority with less mechanical components or simpler mechanical components:
- The galvanometer is fixed, it does not need to rotate.
- The galvanometer is not necessary for proper AE operation, it is only there to tell the user what f/stop has been computed.
- Upon pressing the shutter release, the diaphragm operating lever on the lens starts descending by simple spring action. While it descends, it operates an electronic wiper brush that "wipes" a special contact pattern. This pattern has a special binary coding to assure the camera's microprocessor will always "sense" the correct position of the lever, even if electrical contact is not 100% perfect.
- Once the correct f/stop is met, the position is locked and the shutter is fired. I think (not completely sure, though), that this is done using only one solenoid, perhaps the same used for firing up the mirror.
There is also a pulley and string on the AE-1, for coupling the shutter speed dial to a potentiometer. But this could have been removed as well. In any case the string path is much straighter and simpler than in the EF.