Leica Showcase Nikkor 13.5cm F4 Leica Mount, on the M9.

This lens is rare, one of the original offerings for the Nikon I. About 900 made, most in S-Mount, "a few" in Leica mount, and 1 in Exacta Mount. I don't know how many a "few" is; 300 of the 700 Nikkor 5cm F1.5's were made in Leica mount.So I am guessing "less than 300"?

David Douglas Duncan used a Nikkor 13.5cm F4 lens along with a Nikkor 5cm F1.5 on a pair of Leica IIIc's to photograph "This is War", which includes some of the most famous photographs in history.

I've read that the 13.5cm F4 and 5cm F1.5 were not as good as the 13.5cm F3.5 and 5cm F1.4 that replaced them, that the latter were sharper and faster. The older lenses are just as sharp, Nikon probably decided that they needed to "one-up" the Zeiss 5cm F1.5 Sonnar and 13.5cm F4 Sonnar to compete. In terms of actual speed gain- more marketing.

ANYWAY! First day out with the 13.5cm F4. It's good. It's also rare, and the 13.5cm F3.5 is a fraction of the price that I paid for this one. Optically, equal.

Nikkor 5cm F1.5 and 13.5cm F4

The 13.5cm F4 serial number shows it's from the batch ordered in April 1949, the 5cm F1.5 was ordered in May 1949. These lenses are from the same batch used by DDD. Small batches.

Nikkor 5cm F1.5 and 13.5cm F4
Wide-Open, Close-up.

If you ever read anywhere that this lens is not sharp, they have a bad example. Even wide-open, color-aliasing was visible at 100% crops. This lens is sharp enough wide-open, and really sharp at F5.6.

Gunston Hall