Mystery Brass Lens 90mm f4

Lens Data

Lens Unit

Lens Photo

製造 :不明
使用目的 : 不明
レンズ構成 : 不明だが、反射とレンズ形状から右図のように想定される。既存のデザインには見当たらない。

Production : unknown
Purpose : unknow
or CRT screen shooting or for TV Camera?


Lens Impression



There is completely no information about this lens.
It has no name or data on its body, and I could not check the edge of each glass because they are fixed with surrounding rings firmly.
The most characteristics of this lens are,
  1/the latter face of the last lens has Concave curvature instead of the usual convex face. It is possible to have concave lens at last as shown in the assumed image of
    its lens composition as doublet which can be judged from the number of reflections of the lens.
  2/it has a small doublet lens on the front group.
  3/the focal length is very short to fit Leica S2 smoothly.

The description of this lens is as a restive horse. Strong aberration covers all over the picture except the center. Chromatic aberration remain rather strong , but I can
 estimate it should be intentional to appeal the soft effect on B/W photos at that age.
It showed imaged effect on photos taken in studio with B/W ( refer examples below)..

 Photos with Mystery Brass Lens
Nakano, Otsuka

(モデルをお願いした、みきさん、莉子さん、志帆さん ありがとうございました。)




It is the very first time to take photo of models in studio.
As I prefer taking photos of casual people living, I did not dare to step in this area.
I do not accostomed to such situation yte, I enjoyed the precious opportunity.

Stron achromatic aberration can be obserbed at the edge of haris and others. On the other hand, it makes the figure of models rather soft and confortable. I understood the intention of lens designer.

You can confirm all aberrations in photos of last parts.
As if I see the line-dance of all kinds of aberration.