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Lens review

Nikon Nikkor AF 50 mm f/1.8D

20 January 2010
Szymon Starczewski

7. Coma and astigmatism

Fast prime lenses often have problems with coma. The Nikkor 1.8/50 is not an exception to that rule and the coma in the frame corners at the maximum relative aperture is so huge that we can simply call it a textbook result.

On stopping down we see a significant improvement but even by f/2.5-f/2.8 that aberration is still visible as the spot image of the diode is clearly deformed. On full frame the coma can be perceived even by f/4.0.

Nikon Nikkor AF 50 mm f/1.8D - Coma and astigmatism


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An average value of astigmatism in the case of the Nikkor 1.8/50 on the D200 amounted to 17% which is a significant amount. This is an effect of weak performance by f/1.8 and f/2.0 where astigmatism is mainly responsible for the image quality decrease. On the full frame of the D3x, as the measurement areas are further apart from the optical axis of the instrument, the lens faces even more difficult task. Although the result of 20% didn’t surprised us at all, we weren’t pleased with it either. Perhaps too much plastics in the barrel?