Arnold wrote: 1.) The *ist D KNOWS when there is no lens in A position. It treats all lenses that are not in A position equally. This is fine, as to enable stop down metering for all such lenses (including srew mount and manual aperture k-mount lenses) there is no need to distinguish between them. All that is needed is to release the aperture lever when metering with any lens not being in "A" position, disregarding wheter the lens has an aperture lever or not.
REPLY: A screw mount lens will be stopped down when mounted. A K/M lens will be wide open regardless of aperture set on the lens. Hence, the camera need to stop down (with a motor) when metering with the latter. How does it know it is a K/M lens and not a screw mount lens? This will be an awful solution both technically and in use only to please extremely few users. What if you forget to active DOF preview when metering? What if you accidentally use the same procedure with an FA lens out of habit? Is the exposure value remembered by the camera or are stucked in manual mode only? If it use exposure lock then the camera must be designed so that it locks the metered value when activating DOF preview only with K/M lenses. The idea is probbaly to make a camera thats easy to use. The above make it truly crippled not to mention confusing. Pentax really had three choices. 1) Stick to the old KAF2 mount. 2) KAF2 with "electronic" metering . 3) Two separate metering systems 1)+2). 1) would probably make the *ist D incompatible with future lenses hence doing the customers no favour. 2) is what they did. 3) would be both awkward in engineering and expensive. Customers won't pay for it. P�l
