Use the up and down buttons to change the aperture. Use the manual focus on the lens and the peaking feature + 1:1 magnification to focus. I never use the IRIS or FOCUS buttons for setting either of these parameters. Plenty of info out there about how to use this camera inc instruction manual. For better control use a separate EVF which has scopes and profiles to help with exposure. It would be nice if they introduced scopes / histogram with a firmware upgrade...........................