Nikon added yet another two-letter abbreviation to its lens lexicon today – PF – which stands for "Phase Fresnel." Below you'll find information on the new technology.
From Nikon USA:
The PF (Phase Fresnel) lens, developed by Nikon, effectively compensates chromatic aberration utilizing the photo diffraction phenomenon*. It provides superior chromatic aberration compensation performance when combined with a normal glass lens. Compared to many general camera lenses that employ an optical system using the photorefractive phenomenon, a remarkably compact and lightweight body can be attained with less number of lens elements.
A general interchangeable lens forms an image on an imaging plane, using the photorefractive phenomenon. The degree of light refraction differs depending on the color (wavelength), and image formation is performed in the order of blue (B), green (G), and red (R) starting with the portion near the lens (see the diagram below). The color deviation referred to as chromatic aberration induces color bleeding, resulting in a deterioration of observed or captured images.
With PF (Phase Fresnel) lenses, on the other hand, image formation is performed in the order of red (R), green (G), and blue (B) starting with the portion near the lens (see the diagram below). By combining the PF (Phase Fresnel) lens with a refractive lens, chromatic aberration can be effectively compensated.
Chromatic aberration compensation with the PF (Phase Fresnel) lens