Sorry in advance for asking an equipment question in this thread, but I figured this is the right audience.
A lens for my RZ67 Pro II is acting up, and while it is just a nuisance (not really a problem, since there is an easy hack) I am curious if this can be fixed.
When I install my 210 mm apo, at first everything is ok: The shutter is open as it should be, so I can see an image when looking through the viewfinder. I then put the camera on the passenger seat of my car and drive to my location. The camera is off during all this. Upon arriving, I notice that the shutter has closed randomly, meaning I can no longer see anything through the viewfinder (yes, the lens cap has been removed). My hack is to put the lens cap back on, set the camera to multiexposure, smallest aperture, shortest exposure, expose, and "advance" the film (which will only reset the mirror and cock the shutter). I am then ready to expose for real, and switch out of multiexposure when I get the frame.
How would I go about diagnosing this? It routinely happens on just this one lens.