Lens Reviews Explained
This shows how the lens’s illumination falls off towards the edge of the frame. For easier visualization the display is posterized in third-stop steps. The shades of grey used represent accurately the magnitude of the falloff; because the initial third-stop is essentially imperceptible to the human eye, we have removed it to simplify the graphic.
An additional feature, again thanks to our collaboration with DxOMark, is the Falloff graph. This provides some extra information about how severe the vignetting will appear on your images. If the graph falls dramatically towards the corner of the frame, the vignetting will likely look more objectionable compared to a lens with similar corner illumination but a more gradual drop-off in brightness across the frame.
Falloff – shows the maximum falloff value at the far corners of the image
As with the other displays, you can choose to hide the graph, and see a representation of the light falloff pattern across the entire frame.
Unchecking the 'Posterize' box allows you to see the falloff pattern as a gradient, rather than posterized. In essence this is what you'd see if you shot an evenly-illuminated plain white wall at the chosen settings. Hairlines are included, showing the same 1/3 stop increments as in the posterized display.