What were the basic design concepts behind the development of the AF-S NIKKOR 58mm f/1.4G?
Sato: "There were two important elements. The first was to develop the basic design concept of the Noct Nikkor, achieving superior reproduction of point light sources as point images without distortion or fringes while retaining higher resolution than that of the Noct Nikkor.
To be exact, sharpness, contrast and resolution have been greatly enhanced even for shooting distant scenes. Especially, the lens' sharpness is overwhelmingly superior to that of the Noct Nikkor. Besides this, because sagittal coma flare is effectively reduced, the degree of point-light-source reproduction in the form of points has been further evolved to extend the range to the outer areas of the frame. Also, subjects located even at the peripheries can be depicted without edge distortion. Branches of a tree or parts of a car, for example, can be reproduced in a way that Noct Nikkor could not do as well. All of these factors make your shooting more comfortable. And unlike Noct Nikkor, you can attain these without stopping down the aperture to f/2.8, f/4 or f/5.6 but at the maximum f/1.4.
Why was the maximum aperture of f/1.4 selected?
The main reason is to retain brightness with minimized peripheral light falloff. While featuring a 58 mm focal length as a homage to the Noct Nikkor 58mm f/1.2 lens, we selected the f/1.4 maximum aperture for this reason.
Generally, large-aperture lenses are likely to suffer from peripheral light falloff. However, the AF-S NIKKOR 58mm f/1.4G retains brightness with minimized light falloff even with the focus distance set to infinity at the maximum aperture.