Nikkor AF 50mm f/1.8 D - Review / Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)

Distortion

As expected for a fix-focal lens the level of (barrel) distortion is very low (0.26%) and nothing to worry about.

The chart above has a real-world size of about 120x80cm. Possibly things may get a little worse with extreme close-ups.

Vignetting

Thanks to the sweet spot behavior on the D200 vignetting is very well controlled. Wide-open vignetting is a little stronger at ~0.66EV which may be visible in very critical scenes. From f/2.8 and up the problem is negligible.

MTF (resolution)

Update 04/11/2006 - tested new sample which performed better at the borders.

Standard lenses are stellar performer when used at medium aperture settings and the Nikkor AF 50mm f/1.8 D is no exception here. At f/4-f/8 the lens is surely as good as it gets on the D200 with an excellent center and a very-good border performance. Nonetheless it is also fairly typical for ultra-large aperture lenses that things aren't quite as rosy at wide-open aperture but the center is already excellent here whereas the borders are a bit soft (combined with rather low contrast). From f/2.8 and up the distribution of the MTF50 curve suggests that the center performance exceeds the quality of the D200. The borders improve continuously with good figures at f/2.8 and very-good results at f/4.

The lens showed slight residual spherical aberrations (focus shift when stopping down).

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Chromatic aberrations (color shadows at harsh contrast transitions) are relatively pronounced for a fix-focal with an average pixel width of 1.2px at the image borders. Nonetheless it´s not a major problem. Stopping down improves the issue to moderate figures.




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