Is from the a6500 online help.
- When you set [SteadyShot] to [On]/[Off], the SteadyShot settings of the camera and lens switch at the same time.
- If a lens equipped with a SteadyShot switch is attached, the settings can only be changed using that switch on the lens. You cannot switch the settings using the camera.
I believe that you are referring the focus hold button which can be reprogrammed for many other tasks, including Eye-AF for cameras such as the A6500 which have Eye-AF capability but, not continuous Eye-AF. You can also program it for AF-on which can take the place of back button focus...AlwaysOnAuto - I believe in most cases, you can actually set the on-lens button to do something custom, including other camera body functions. I think all it probably does is send a signal to the camera, which then does whatever is necessary to carry that out.