Peter Alling <[EMAIL PROTECTED]> wrote: >I'm not sure how this works but, the only time you see the f Stop displayed in >the finder with A lenses is when you use the A setting on the lens. Weather >the value displayed comes from the lens or is the setting the camera will >attempt >I don't know.
Tha answer is to be found (of course) on Boz's web page: http://www.bdimitrov.de/kmp/extras/K-mount/Ka.html "Displaying Aperture in the viewfinder "In the Tv and P operating modes the body decides how many f-stops the lens will be closed down during the exposure. Consequently, knowing the narrowest aperture and the number of f-stops allows the higher-end bodies to calculate and display the selected f-stop. "But why does this not happen in the M and Av modes? After all, knowing the positions of its stop-down coupler, the body should be able to calculate how many f-stops the lens is closed down. Knowing the narrowest aperture and the number of f-stops, the body could calculate the widest aperture, and then the manually-selected f-stop. Yes, but only for prime lenses! Variable-aperture zooms have fixed contact patterns, and can therefore only indicate a fixed aperture range. In this case, the incorrect f-stop may be displayed in the viewfinder, and I guess that because of this, Pentax left the feature completely out. Note that due to the TTL exposure metering, the film will be exposed properly regardless of the fact that the f-stop's numerical value may be calculated incorrectly." -- Mark Roberts Photography and writing www.robertstech.com
