Sun 10-Feb-13 08:46 PM | edited Sun 10-Feb-13 09:28 PM by Ferguson
>>>> Please ignore this post it's just plain wrong <<<<< (left for context)
>You are correct. The auto setting for minimum shutter speed >in the auto iso setting only allows for whole stop adjustments >to the reciprocal calculation. This allows of -2, -1, 0 +1 >and +2 EV adjustments to the reciprocal, but not half-stop >adjustments. So you could not dial in an automatic 1.5X >adjustment.
But what you can do is dial in 1.5 (or 1.3 or 1.7 depending on your settings) additional base minimum speed. Use the auto adjustments for what it's intended (I think), which is different scenarios not cameras, and then it scales properly since you already put the pixel density factor into the base speed.
I interpret the +/- auto adjustments more about scenario/subject, so for example if it's really pretty dark, I might dial it down to trade a bit of camera shake to avoid being in the stratosphere of ISO, or I might dial it up if what I'm shooting is more action oriented (I realize the auto scaling is more about focal length and camera shake than action, but usually if the subject is moving fast so is my camera to follow).