Here is a lens that was manufactured by the famous optical company Tomioka and put on a number of M42 screw mount cameras under different names: Mamiya-Sekor, Chinon, Rikenon, Revuenon, Cosia, Porst in Germany and Sears in the USA. There are several versions of the lens, and this is the earliest. The lens has seven elements in five groups, basically a standard double gauss design with an extra converging element at the rear. Legend has it that this lens is very similar in performance to the uber-rare and expensive Zeiss Pancolar 55mm f1.4. The optical formula is the same and both are radioactive. I have the Pancolar, and have been very curious as to whether the performance and bokeh were truly similar. After all the character of a lens does not depend solely on the optical configuration, the element thicknesses and curvatures, the glass used, and the spacing all play a large part in how a lens performs and renders. So when I found this lens at a junk market for 40 euros (about 3% of the price I paid for my Pancolar, I jumped on it. I truly didn’t believe that this common Japanese lens could approach the performance of the legendary German lens.
I was wrong. After extensive testing I can say that the performance of the lenses: the sharpness and bokeh, are nearly identical. Had I known I would never have bought the Pancolar. The most obvious difference is in the focal length. Though both are marked 55mm, the Sears is closer to 52mm by my calculation. Beyond that, the sharpness, contrast and bokeh are hardly distinguishable. Here is an example. The Sears has been shot slightly closer to compensate for the difference in magnification. There is a very small difference in the weighting of the illumination of the bokeh OOF discs. Very small. The shapes are identical, and it was here that the Pancolar stood out, as the shapes of the off axis discs was quite distinctive as compared to other 50 and 55mm lenses of this speed. In the department of bokeh shapes, the Sears is virtually identical to the Pancolar. Not exact, but very close. Judge for yourself:
In terms of construction, the lenses are clearly different. The element sizes are significantly different, as is the length of the lens. But somehow, apart from the focal length, Tomioka has recreated the Pancolar nearly exactly. If you love the Pancolar, buy this lens instead, and get the same performance for thousands of dollars less 🙂
