An impressive result here, there are not many modern lenses, if any, that can compete with this lens in this category. Wide open there is a small amount of vignetting, which is not very disturbing. Close the aperture one stop and there virtually no visible vignetting. You may wonder how this is possible that this vintage less has this impressive performance here, well light fall-off is a result of light passing through glass elements, the more the angle (near edges) the more fall-off. Here we have the minimum number of glasses, only three, which explains the reason.