Lens review

Nikon Nikkor AF-S 16-35 mm f/4G ED VR

7 January 2014
Arkadiusz Olech

7. Coma, astigmatism and bokeh

In the corners of the smaller DX sensor the coma is corrected very well. Unfortunately the situation changes in the corners of full frame where the coma becomes clearly visible at every focal length. It is the most troublesome at 16 mm and it disturb you the least at 35 mm but no matter where you look it contributes noticeably to the deterioration of the image quality in the corners.

Nikon Nikkor AF-S 16-35 mm f/4G ED VR - Coma, astigmatism and bokeh

When it comes to the astigmatism we don’t have any good news either as that aberration is distinct and bothersome at every focal length. Its textbook form at 35 mm is presented as a graph shown below.

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Nikon Nikkor AF-S 16-35 mm f/4G ED VR - Coma, astigmatism and bokeh

The difference between vertical and horizontal MTF50 values is clearly noticeable near the maximum relative aperture and decreases on stopping down. The aberration is visible up to f/11 and only in the range from f/16 to f/22 it stops influencing the image quality.

If you average out the results across all the focal lengths and for two maximum apertures, it reaches 11%. However if you take into account just the maximum relative aperture results, the astigmatism can amount to almost 20%.

We don’t have any serious reservations concerning the appearance of blurry images for a change. The defocused circles of light show some local extremes and not very bright rim on the edge but such effects are slight, easy to reconcile with.

Nikon Nikkor AF-S 16-35 mm f/4G ED VR - Coma, astigmatism and bokeh