The comparisons presented below were shot on a perfectly clear day. Exposures in-camera were identical, but that does not mean that all images were the same brightness. For example, the 24-70 L II delivers images that are about 1/2 stop brighter than the 24-70 L I at 24mm. Therefore, all images within a focal length were brightness-matched at a central near-white point in the frame (using DPP) to make these comparisons easier to use. Differences in brightness in the comparisons are typically caused by vignetting at the wider apertures (these samples were taken from the outer portion of the image circle).