exposure mode. Just full aperture manual or aperture preferred mode would be all most
would ask for.
John Mustarde wrote:
If the Daddy-D comes with full aperture coupling, driven by a stepper motor or some such, Pentax could build a settings function, whereby the camera remembers the aperture lever positioning requirements for any particular lens. This would calibrate each lens one by one to compensate for any difference in linearity of its aperture mechanism. The setting function would be primarily for K and M lenses, but could be used for any lens operated in manual aperture mode.
The operator would input settings for each lens, perhaps based on in-camera histogram level tests made with the exact lens to be used, limited perhaps to even f-stops for simplicity. Plus the operator would choose that setting each time the lens in question was mounted.
But it is possible to do this, if driving the aperture actuation lever position can be computerized and individualized. It's also likely very usable if the setting was one-button and you just had to quickly press through the two or twelve K lenses you own to get to the one you were about to mount.
So you attach your M20/f4, assign it a name within the camera computer (like "M20/4"), take exposures at each aperture click stop, calibrate a curve using the histogram for each f-stop, check exposure, loop back if needed until the exposures are spot-on at each aperture, save the setting, then do the same for the old Vivitar Series 1 90-180/4.5 Flat Field Macro Zoom ("Viv90-180"), followed by the M200/2.5, etc until every K or M lens in your bag had its name and calibration in memory. This is a simple calibration sequence like those used in industry every day.
Switching the lenses around would require selecting the name of the lens from a menu or better yet a single-purpose button. Sounds very feasible, and very much a value add proposition for the Daddy-D to me. I'd pay and extra fifty bucks for this feature.
-- John Mustarde www.photolin.com
