Nikkor Ai-S 50mm f/1.8 - Review / Lab Test Report - Analysis
Lens Reviews -
Nikon / Nikkor (APS-C)
Page 2 of 2
As expected for a fix-focal lens the level of (barrel) distortions 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.
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.
Below is a simplified summary of the formal findings. The chart shows in line widths
per picture height (LW/PH) which can be taken as a measure for sharpness.
The chart is limited to the visually relevant LW/PH range of [750, 2250].
If you want to know more about the MTF50 figures you may check out the corresponding
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.