I set my Pentax K100D to Auto ISO 200-800.
And, additionally, mostly in aperture priority mode.
Now, when the exposure time gets long, let's say, under 1/60th, I expect Auto ISO to kick in and increase the ISO to 400 or more.
But when it gets darker, the shutter time gets longer and longer, and I finally have to change the ISO by hand to a higher value.
Is it me, or is it the camera? Does Auto ISO only work under certain circumstances?
Thanks.