Lens review

Canon EF 35 mm f/1.4L USM

8. Vignetting

It’s another interesting category, which shows how much we gain using smaller detectors. On the Canon 20D, at maximum relative aperture, the illumination loss in the frame corners is 32% (-1.11 EV). It’s a lot and we are afraid to think what will happen on the full frame but it must wait a moment. Fortunately, on stopping down to f/2.0 the vignetting level decreases to 16% and by f/2.8 makes the problem practically disappear (8%).

The situation we’ve observed on the 5D camera makes your hair curl and requires a new definition for the “high vignetting” notion. You can only describe the results as monstrous, gigantic, very, very huge vignetting because nothing else renders the effect when, at the maximum aperture, we lose 70% of the corner illumination (-3.5 EV). On stopping down the results are slightly better, which doesn’t mean good. By f/2.0 the vignetting reaches 50%, by f/2.8 – as much as 35% . by f/4.0 – 27% and by f/5.6 it decreases to the level of 22%. Only by f/8.0 we get the acceptable level of 18%.

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Such a significant vignetting level is not without influence on real life pictures. If you have a look at no. 10 and 11 miniatures you’ll notice that the cloud in the right-hand bottom corner, which seems to be black and stormy by f/1.4, is, in fact, white, like in another picture, taken by f/5.6…