July 2021 Part 1 — This Month Through Your Adapted Lens

Started 2 months ago | Discussions thread
Albert Silver Veteran Member • Posts: 3,373
Info and design of Mamiya-Sekor 55 f/1.4

Travis Butler wrote:

Albert Silver wrote:

So, the title warrants a bit of an explanation.

I commented elsewhere on the exceptional quality of my copy of the Mamiya-Sekor 55mm f/1.4, which is fine, and this was noted when I disassembled it to check and clean if needed. The problem is that I seem to have screwed up the minimum/maximum focusing on it.


Mamiya-Sekor 55mm f/1.4 shot at f/1.7 (focus on foam) on Nikon D750

Well, at least this result does look very nice...

Picked up a copy of the lens myself Thursday, at a local sale; haven't had much time to play with it yet, given time and weather. Very much looking forward to the pics now!

A couple of online references called it a Tomioka lens; the build quality and mechanics feel very close to my Yashinon-DX 50/1.4, so that seems fairly credible to me. Do you have any further information?

Of the old legacy 55-58mm lenses I have acquired, it is the clear champion in performance so far. This is comparing it against a Mamiya Sekor 55 f/1.8, the Cosinon 55 f/1.4 (though the Cosinon has a smoother bokeh as a rule), the Super Takumar 55 f/1.8 (the worst of the lot), the Auto Chinon 55 f/1.7, and the Helios 44M-7 (the best of this Helios series) 58mm f/2.

I have read a much repeated (presumably from the same source) comment that the Mamiya-Sekor 55 f/1.8 is as good or even better, and all I can say is that is utter bunk, though sample variation may be a factor here. The f/1.8 is perfectly fine, but it is unquestionably a worse performer. The f/1.4 is better at f/1.7 than my f/1.8 is at f/2 and roughly equivalent to it at f/2.4.

Here are some links:


Regarding Tomioka:


"all of them have 3 lenses in 3 groups (typical Ultron scheme). Only the 55/1.4 lens, has 3 lenses in 2 groups (one cemented doublet). => all Tomioka (Yashica) standard lenses are based on Ultron scheme, but Tomioka 55/1.4 isn't"

I can confirm that there is a cemented doublet.

Optical design:

http://www.klassik-cameras.de/Rolleiflex350_en.html (see bottom description)

Mamiya-Sekor 55 f/1.4 design

The page's author notes that it looks identical to Carl Zeiss's Planar of the period and speculates whether the design was not sold.

Design of Carl Zeiss Planar 55mm f/14 built for for the Contarex SLR from 1961-1970

 Albert Silver's gear list:Albert Silver's gear list
Nikon D750 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II Sigma 24-105mm F4 DG OS HSM Tamron SP 35mm F1.8 Di VC USD +1 more
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