Despite the CFV-50c’s straight-forward design, using it can take some getting used to. We tested the back on the classic 500 C/M, a fully mechanical 6x6 SLR. Because it’s an SLR, the camera must be placed into mirror lock-up mode in order to see a Live View from the sensor. Another thing that tripped us up is the fact that sensor is not always “on”. After the CFV-50c detects that the shutter has been fired, it becomes active for an exposure time that’s selected in the back’s menu options. It took us a minute to realize that this exposure had to be longer than the shutter speed set manually on the lens’ leaf shutter.