Nikon 24mm 2.8 AI on Sony A7

My Nikon 24mm 2.8 AI was produced in the late 70s. Galen Rowell took some of his famous shots with the AI-S version which is optically the same. He shot with a camera which was built for film. Film and modern sensors are very different regarding angular incident light. Cause I don't shoot with a Nikon but with a Sony I need additionally an adapter. This 24mm lens has floating elements which correct the near distance focusing. If you have an adapter which doesn't have exactly the correct flange distance, you may get quality loss. Let's see how the 24mm AI competes in the digital era with adapter.

Clicking on a crop loads the whole image in original size. A tip for Retina display users: Zoom in 1.5x or 2x. Otherwise you are not really in 1:1 mode. Images are developed from RAW files in Ligtroom 5. All adjustments are Lightroom standard (sharpness: 25/1/25/0).

Conclusion Nikon 24mm 2.8 AI

Is it the lens, is it the adapter, or is it both? The lens gets really sharp in the center. But the rest does not. It's better than the Tokina 24mm 2.8, but it's far away from what I would call acceptable. If you have nothing better, it's usable at f/8 or f/11. Real pleasure is a different thing. You can correct the vignette and the chromatic aberrations, but the missing sharpness at the edges and in the corners you can not. The lens has a distinct field curvature. When you focus on the edge, you get a sharper edge but not a real sharp one. The center and corners are blurry now. Look at the images at f/5.6 above.

Does the adapter deteriorate image quality? May be, may be not. The adapter I use is from Novoflex. It's not a cheap one. But from what I've heard the adapters of Novoflex are 0.1mm up to 0.2mm shorter than the correct flange distance. With this trick, focusing to infinity is always granted even with big plus tolerances. Well, I could try shimming the adapter to correct length. Or I could buy an even more expensive adapter from Kipon. Kipon is well-known for smaller tolerances. Neither I will do. The chances to get eventually a sharp lens across the frame are too little.