Obviously, someone made a silly mistake entering data into the web site, entering the lens' widest ƒ stop in a field that ought to have been the focal length.
It does make me wonder about something.
In an SLR, there is only so close that the lens can actually be to the focal plane without running afoul of the mirror. Just off the top of my head, it seems that a good rough estimate of this minimum distance would be the height of the frame multiplied by the square root of two—so with a DX-format sensor, about 22 millimeters, and for an FX-format sensor or a stone-aged 35mm film camera, about 34 millimeters. Taking a look at the mirror chambers in my D3200 and my F2, it looks like the minimum distances are significantly greater than these.
Aside from the mislabeled “2.8mm” lens (which is really a 300mm lens), Nikon does have, listed on its web site, DX-format lenses as short as 10.5mm, and FX-format lenses as short as 14mm. Clearly, it is not possible for any part of these lenses to physically be that close to the film plane.
It occurs to me that I ought to know a term that refers to the point within a lens which, with the lens focused at infinity, is the distance from the focal plane that is that lens' focal length, but I can't recall such a term, and a quick perusal of some articles on the Wikipedia that ought to tell me that term, if it exists, do not.
Whatever the term is for this point, is it possible for it to be outside of the actual physical structure of the lens? Is it possible for a lens to have a focal length of, say, 10.5 millimeters, without any part of that lens needing to be any closer to the focal plane than 22 millimeters?
Now that I think of it, I suppose even the stock 18-55mm lens that came with my D3200 must be an issue, here. There's no way that any part of it is ever as close as 18 millimeters to the focal plane. I'm leery of needlessly sticking anything far enough into my camera to make a usable measurement, but eyeballing it, it certainly doesn't look like anything less than about 30 millimeters at least, from the focal plane to the very rearmost reaches of how far into the camera any part of the lens goes.