Nikon NIKKOR-S Auto 50mm f/1.4

Lens Construction

MTF Performance

Here is how the lens performed according to Imatest:

Due to very strong spherical aberration issues, The NIKKOR-S 50mm f/1.4 shows weak performance at the maximum aperture. On top of that, the lens suffers from field curvature, which results in blurry mid-frame and corners. And even worse, there is a very noticeable focus shift when going past f/2. In order to produce the above numbers, I had to reacquire focus at each aperture all the way to f/5.6.

Stopping down to f/2 improves sharpness in the center quite a bit, but the rest of the frame stays very weak until f/2.8. At f/4, the effect of spherical aberration and field curvature is significantly reduced, resulting in much better overall performance. Center sharpness is very impressive at f/4 and peaks at f/5.6, where the lens produces exceptionally sharp images across the frame. Best corner performance is reached at f/8.

Distortion

There is a little bit of visible barrel distortion, but it is not too noticeable – better than on the NIKKOR 50mm f/1.2 Ai-S. Imatest measured barrel distortion at -1.10. Unfortunately, since neither Lightroom nor Camera RAW have built-in lens profiles for this classic, all distortion corrections have to be carried out manually.

Chromatic Aberrations

Chromatic aberration levels are fairly low when compared to other classic 50mm lenses. Imatest measured CA at under 1 pixel on average, as shown below:

Vignetting

Vignetting is extremely strong wide open, reaching as many as 3 full stops of difference in the corners. As the lens is stopped down, vignetting is reduced considerably – by f/4, it is almost completely gone:

Here is an illustration of the worst case scenario, shot at f/1.4: