Some mirrorless cameras use ‘focus peaking’ as a means of indicating what is ‘in focus’ in a scene.
Focus peaking overlays the preview image with a solid colour to indicate where the intended subject is sharply focused.
Focus peaking can also indicate approximately how much depth of field a lens is producing: the more of the previewed image that is coloured, the more of it is sharp, so the greater the depth of field. You should see that the areas in front of and beyond the sharply focused point come into focus at the rate of approximately one third in front and two thirds behind the actual point of focus.
Most cameras will also allow you to select the choice of overlay colour, to ensure that you can determine what’s in focus against the background. We’ve provided a simulation of focus peaking here to give you an idea of what it looks like.
Focus in Photography is John Neel’s exploration of advanced focus that will greatly enhance your skill as a photographer. These pages will show you everything, from high-end techniques to create infinite focus, through to using it as an artistic tool, directing your viewer’s eye around your photographic composition.