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Lens review

Canon EF 16-35 mm f/2.8L III USM

4 December 2016
Szymon Starczewski

7. Coma, astigmatism and bokeh

As long as you work using an APS-C class detector coma shouldn’t be a problem whatsoever. It is a result noticeably better than in the case of the predecessor because its coma was noticeable already at the smaller detector. In the corners of full frame the situation is not so good anymore. As in the case of the shortest focal length you still can call the coma level acceptable, in the 24-35 mm range it becomes significant. These results still are better than the results, for instance, of the Tokina AT-X PRO FX SD 16–28 mm f/2.8 (IF) and the Nikkor AF-S 16–35 mm f/4G ED VR; however they are distinctly weaker than the results of the Tamron 15–30 mm f/2.8 Di VC USD or the Canon EF 16–35 mm f/4L IS USM.

Center, 16 mm, f/2.8 Corner APS-C, 16 mm, f/2.8 Corner FF, 16 mm, f/2.8
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh
Center, 24 mm, f/2.8 Corner APS-C, 24 mm, f/2.8 Corner FF, 24 mm, f/2.8
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh
Center, 35 mm, f/2.8 Corner APS-C, 35 mm, f/2.8 Corner FF, 35 mm, f/2.8
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh


The astigmatism, understood as an average difference between vertical and horizontal MTF function values, can be a bit of a problem as well. The value measured by us amounted to 12.2% and it is a medium level. The 35 mm focal length contributes to that result the most because the astigmatism was the most pronounced for that point. It is a value worse than those of many rivals, mentioned in this test.

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For a zoom lens with such a wide angle of view defocused light circles look sensibly well. The light spread observed in them is not completely even – you can notice concentric circles for example – but overall it remains better than the respective performance of the Tokina 16-28 mm or the Tamron 15-30 mm or the tested lens’s slower brother with the same focal range.

Center, 35 mm, f/2.8 Corner APS-C, 35 mm, f/2.8 Corner FF, 35 mm, f/2.8
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh
Center, 35 mm, f/4.0 Corner APS-C, 35 mm, f/4.0 Corner FF, 35 mm, f/4.0
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh
Center, 35 mm, f/5.6 Corner APS-C, 35 mm, f/5.6 Corner FF, 35 mm, f/5.6
Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh Canon EF 16-35 mm f/2.8L III USM - Coma, astigmatism and bokeh