Nikkor Ai-S 50mm f/1.8 - Review / Lab Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)
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As expected for a fix-focal lens the level of (barrel) distortion is very low (0.21%) and nothing to worry about.

The chart above has a real-world size of about 120x80cm.


Thanks to the sweet spot behavior on the D200 vignetting is very well controlled. Wide-open vignetting is a little stronger at ~0.61EV which may be visible in very critical scenes. From f/2.8 and up the problem is negligible.

MTF (resolution)

Standard lenses are stellar performer when used at medium aperture settings and the Nikkor Ai-S 50mm f/1.8 is no exception here. At f/4-f/8 the lens is as good as it gets on the D200 with an excellent center and a very-good to excellent 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).

It is interesting to note that the MTF curve is basically identical to the one of the AF 50mm f/1.8D.

Please note that the MTF results are not directly comparable across the different systems!

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 well controlled and slightly lower than in the tested AF variant.


The Nikkor Ai-S 50mm f/1.8 performed basically identical to the current AF D model so it's your choice whether you prefer AF and a plastic construction or smooth manual focusing in a solid package. At wide-open aperture it is a little soft at the image borders and the contrast level is a little on the low side. However, at medium aperture settings the resolution figures are exceptionally high. Distortions are negligible and vignetting as well as CAs are very well controlled.

Optical Quality:    
Mechanical Quality:
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