I recently set my camera to Auto in settings and set up AUTO ISO as well in the settings. Auto ISO 1, default sensitivity to 160, max sensitivity to 12800 and min shutter speed to 1/60. Dial on top of camera is set to A. I shoot in Aperture Priority mode and use back button focusing. Every time I look through viewfinder, and move my camera around a scene, the ISO remains on the 12800 number and does not change at all. I cannot figure out why this is happening or maybe if I should check some other settings in the camera. Not sure if back button focusing is causing the issue? Would greatly appreciate any thoughts or suggestions on how I can get the Auto ISO to work. Many thanks in advance.