Tokina AT-X PRO SD 14-20 mm f/2 (IF) DX
7. Coma, astigmatism and bokeh
| 50D, 10 mm, f/2.0, center | 50D, 10 mm, f/2.0, corner |
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| 50D, 17 mm, f/2.0, center | 50D, 17 mm, f/2.0, corner |
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| 50D, 20 mm, f/2.0, center | 50D, 20 mm, f/2.0, corner |
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The astigmatism, understood as an average difference between horizontal and vertical MTF50 function values, amounted to 3.2% which we consider a very low level. It’s worth mentioning that at 20 mm it was slightly higher than for the rest of focal lengths.
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When it comes to the appearance of out-of-focus images it would be difficult to have any reservations here. The light spread is even and the aperture blades make the circles very pleasantly round. You can notice a lighter rim but it is acceptable in the case of a zoom lens. It is obvious the lens has no big problems with the mechanical vignetting – even in the frame corner by f/2.0 the circle we got wasn’t especially truncated.
| 50D, 20 mm, f/2.0, center | 50D, 20 mm, f/2.0, corner |
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| 50D, 20 mm, f/2.8, center | 50D, 20 mm, f/2.8, corner |
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| 50D, 20 mm, f/4.0, center | 50D, 20 mm, f/4.0, corner |
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