Originally posted by lakeshore Interesting feedback.
I have a K-50. Of the 3 parameters (f-stop, shutter speed and auto-ISO) to which, and in what order, does the software give precedence? For example in Auto mode, does the camera decide which aperture to use and then selects the appropriate speed and ISO? Is there a default order to the selection for the various modes?
That's depending on the chosen program line. Program line is the trade off between shutter, aperture and iso and it's only applicable in P and green auto. You can choose the program line in P mode in the menus and you let the camera pick the program line based on focal length and focus distance when in green auto.
I know the "Normal" program line best. It has an inflection point where the light level corresponds to wide open aperture, lowest auto-ISO and 1/Fl shutter speed. In stronger light, it speeds the shutter and closes the aperture evenly. In lower light, it raises the ISO until it reaches max auto-ISO. As the light wanes even more, it starts to slow the shutter.
On the K-3 there's an additional inflection point for lenses f/2.0 and faster. The K-5 didn't have that.
Program line properties are hard to descrive in words as well as in pictures. If you're genuinely interested, I suggest you experiment yourself. Put the camera in P mode, pick the Normal program line and point it at different light levels to study what it does. I assure you it's completely deterministic and it's possible to understand it well enough to use it to your advantage when appropriate.
Regards,
-Anders.