 The ES-LV of its Powershot digicams always kept its apertures stopped down, so no 'aperture exposure simulation' was needed, and briefly opened aperture to assess focus with shutter button partially depressed before a shot is taken.The ExpSim LV of its EOS lens DSLRs could achieve the same 'exposure simulation' effect in both aperture stop-down mode and aperture wide open of its EOS lenses, even if the aperture selection was narrower than widest diameter (wide open).In Autogain framing live view, such as in AE modes with Auto ISO in effect, using the dof button can take on two different effects