Having had an M9, but living in a country with no access to Leica services, I got more and more uncomfortable with the rangefinder calibration issue as the number of my lenses grew. I finally sold the M9 and have been using mirrorless cameras since.
With growing sensor resolution, the mechanical rangefinder-lens coupling is becoming a serious limiting factor.
Now, I was wondering if this could not be solved by replacing this mechanical by an electronic coupling. The position of the rangefinder roller, moved by the rangefinder helix of the lens as the focusing ring is turned, would be electronically measured. This measured position would then trigger the adjustment of the position of the rangefinder patch, for example using a servo or a digitally produced patch in an arrangement similar to the one used in the Fuji X-Pro1.
The obvious advantage of this is that no mechanical adjustment or calibration is required. Both RF roller and RF patch would never need to be adjusted after initial build of the camera. All adjustments and calibration could be done via software using a calibration profile for every camera-lens couple. This calibration could even be done by the enduser with the help of an EVF and a software supported procedure.
So one would set a calibration profile for every lens he wants to use on his camera, and the camera would upload the corresponding profile every time the lens is mounted. For lenses with strong focus shift, the owner of the camera could also choose at what aperture the calibration is done, depending on his preferences.
If this is possible, the list of improvements would be long, among them:
- software calibration allows to perfectly calibrate a camera with an unlimited number of lenses, which is very hard to do with a mechanical coupling
- in the field calibration is possible, with no risk of damage
- as the RF roller is not adjustable, the calibration will not be lost du to excessive vibration or mechanical shock
- focus shift can be taken into account
Again, if this is possible, one would have the pleasure of using rangefinder focussing without the hassle of maintaining mechanical calibration.
If this has already been suggested or discussed elsewhere, donít bother, but if not, I would be happy to have your opinion about the idea.