How to code the pre-asph 35mm Summilux?

[scott kirkpatrick]

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There are sensors which read the position of the frame select lever, but because of the way the mechanical linkage works (see Mark Norton's Anatomy lesson), the sensor only picks up displacement of the lever towards the lens. (So if your lens brings up the 35 mm frame, the camera can see when the frame lines are shifted to 50 or 90. When the lens brings up the 50 frames, the camera can see the frame lever displaced to 90, but will not notice if you pull the lever back to 35. When the lens brings up the 28/90 frames, you can whatever you want with the frame lever, but the two microswitches involved will not be affected, as they are both pinned by the setting on the lens mount.

 

Carl Bretteville found that the 6 bits of the lens ID and two bits for the frame lever were mapped into a convenient 8 bit word in the M8's MakerNotes of the EXIF data. I don't know if they have been decoded yet in the M9 EXIF, which is quite different. There is probably a different structure there, which reflects the addition of the manual entry table.

 

scott