Nikon 300mm F4

[MattNQ]

PF = Phase Fresnel

Apparently corrects chromatic abberation in a different way to the usual ED glass lens elements , enabling a shorter/smaller lens.

Design has been kicking around Nikon halls around for a while. Nikon used it in 2003 on a converter for a P&S
Scroll down to the Phase Fresnel paragraph
https://nikoneurope-en.custhelp.com/...tail/a_id/1186

This seems to be the first time Nikon has used it on an SLR lens.

The actual technique has been around for a long time (late 1700's if Wikipedia is correct )
http://en.wikipedia.org/wiki/Fresnel_lens