Its done for convenience. You can see your shutter speed real time and can
make adjustments if its too fast/slow. Pentax could have had a pseudo-AE
mode if they wanted to with just one press of the green button per aperture
selection if they wanted to. By taking two measurements, one wide open, one
with the aperture down, a simple ratio could be used for all future
calculations using the future wide open measurement. If you changed the
aperture, you pressed the green button again.
I believe you're saying the same thing I've suggested in the past.
I have written to Pentax suggesting they implement this as a firmware
option. Of course I haven't heard anything about it by the time the
English-Japanese-English telephone game stalls it out.
-Cory
--
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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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