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Lens review

Nikon Nikkor AF-S 20 mm f/1.8G ED

18 October 2014
Szymon Starczewski

7. Coma, astigmatism and bokeh

As long as you work on an APS-C/DX sensor the coma won’t be problematic at all. The situation changes completely in the corners of full frame where the coma level is high and it contributes greatly to the deterioration of the image quality. What’s more, even on stopping down by 1 EV its level remains significant.

Nikon Nikkor AF-S 20 mm f/1.8G ED - Coma, astigmatism and bokeh


The tested lens doesn’t have any problems with the astigmatism correction for a change. An average difference between horizontal and vertical MTF50 function values amounted to just 3.2% and we consider it low.

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It would be also difficult to carp about defocused images seriously. The light circles do have the onion rings structure but that effect is not especially pronounced and you can’t see any distinct local extremes or rims. You also should remember that, with such parameters, you won’t have a lot of opportunities to admire vast blurred areas in your photos.

Nikon Nikkor AF-S 20 mm f/1.8G ED - Coma, astigmatism and bokeh