So, with the 40d it is not possible to set a minimal shutter speed or the iso range for the auto iso.
In the manual of my 40d it says (if used in AV mode):
"The iso speed will be set automatically within iso 400-800 so that a shutter speed preventing camera shake will be set ..... "
What is this shutter speed? How does the camera calculate the minimum shake - less shutter-speed and does it consider focal lengths for instance?
Does that make it a bit clearer? Was a bit confusing maybe without reading the manual, sorry english is not my mother tongue.....