The lens will only stop down to the setting on the aperture ring in Manual mode when you press the green button, operate the optical DOF or release the shutter. The iris will stop down in B or X mode when you use the optical DOF preview or take an exposure.
In Manual mode when you press the green button the iris stops down to the ring setting, the camera takes a meter reading and sets the appropriate shutter speed. When press the shutter release the lens stops down to the ring setting and takes the exposure at the shutter speed set by the green button.
On "flagship models" (K10D/20D, K-7, K-5, K-3, K-1) if you operate the optical DOF preview the lens stops down and the EV is shown as a bar meter and you can zero the EV by turning the eDial for the shutter speed or change the aperture with the aperture ring. Pressing the shutter release stops down the lens to the ring setting and uses the shutter speed set by the eDial.
Pressing the green button in Av mode should do nothing unless you programmed the green button to do something else.
Last edited by Not a Number; 12-21-2019 at 01:06 PM.