This pair of images shot on film shows very clearly - no digital sensors involved - the actual vignetting at f2.8 (top) and f8 (bottom) given on full frame by a modern fast wide zoom lens, the Sigma EX 20-40mm f2.8 used at 20mm. It is not helpful for reviewers to slate full frame digital sensors for vignetting problems without making a comparison on slide film (not print film viewed through an enlarger either, because optical enlargers suffer from reverse vignetting which compensates). Projectors also have vignetting, and so does the typical projection screen relative to the human eye, so a slide viewed could have extra corner darkening added, compared to a digital file viewed on-screen.
