Mamiya Sekor 55mm F/1.4 USM Lens Review

2000 1125 Albert Silver

For many photo-enthusiasts, the name Mamiya will evoke a long line of highly respected medium format cameras which for decades were the workhorse of professional photographers. However, during the 1960s and 1970s they also forayed into the 35mm market, producing film rangefinders and standard SLRs under the Mamiya-Sekor name that curiously used no fewer than six different mount types over time. 

Most of the SLR cameras used the M42 universal screw mount and came with one of a series of compact high-quality standard focal length primes bearing the Mamiya-Sekor name, which ranged from a 50mm f/2 lens on the lower end to the premium 55mm f/1.4 at the higher end. 

When I first felt the lure of adapting vintage lenses to my Nikon DSLR, the Mamiyas soon came under my radar thanks to the famous brand name, the unanimously effusive opinions I kept running across, and not least the reportedly modest prices. Great quality and cheap? I was sold. Unfortunately, a quick survey of the findings on ebay seemed to disabuse me of the reputed thriftiness, since all the decent copies were retailing for $90 at the cheapest. I also noticed that prices did not seem to change even if the lens came with a vintage camera. This made it clear: the lens was the driver of the price, not the camera. This situation was described by Prof. Hank Dietz as “lens with a camera-shaped rear lens cap.” 

Finally, after a week of fruitless searches, I ran across a curious case: Someone was selling a shoddy-looking Mamiya-Sekor SLR accompanied by a ‘Vivitar’ 55mm lens per the title, and described as “dirty with dust and grime.” It had belonged to the seller’s grandfather and was sold as-is. Not exactly encouraging, and the zero bids in spite of the $15 price tag said it all. 

Still, what grabbed my attention was the picture: It was small and dark, but I could swear the lens said Mamiya, not Vivitar. Looking at the seller’s further images it became clear that the brand of the lens wasn’t Vivitar, but rather the filter still attached to it, and while indeed grimy, one could clearly read Mamiya-Sekor 55mm f/1.4 underneath. What if the lens were fine, and the filter and camera had protected it over time? I decided to roll the dice, and made the single winning bid.

When it arrived a few days later I was rewarded beyond what I had a right to, since not only did the filter come off and clean nicely, but the lens’ glass was literally in mint condition. As I began to shoot with it and acquaint myself with its strengths and weaknesses, I grew to realize what an absolute gem this was. Had I known how good it was, I would have spent the $90-$100 others were asking in the blink of an eye. As such, beginner’s luck made my introduction to vintage lenses one of wonder and joy. 

Mamiya did not actually manufacture the array of primes that came with their 35mm cameras, and instead outsourced this to a major player in the industry at the time, the Japanese optics firm Tomioka Optics. This wasn’t terribly unusual, and Tomioka was known for providing high quality lenses to a number of Japanese camera makers. In fact, the Tomioka plant also made Carl Zeiss licensed optics for use on some Japanese cameras, such as the Contax. These were made with at least some Zeiss tooling and personnel. 

In fact, while there is no precise documentation to confirm it, there is compelling evidence to suggest the Mamiya-Sekor 55 f/1.4 is either a copy of, or based on, the optical design of the Carl Zeiss Planar 55 f/1.4 built for the Contarex SLR from 1961-1970. Here you can compare the two.

However, even if true there are at least two significant differences between the two: first, the Carl Zeiss Planar is sold for no less than $1,000-$2,000 on eBay, and second, the Mamiya is radioactive. 

This was actually true of a number of top-of-the-line lenses at the time such as the Canon FL 58mm f/1.2, the SMC Takumar 50mm f/1.4, the Konica Hexanon 57mm f/1.2 and many more. The source of radioactivity stems from the thorium added to the glass to improve the optical qualities while also keeping them smaller and lighter. Health concerns on extended use and exposure are well addressed in the 2013 thesis “An Analysis of Residual Radiation in Thoriated Camera Lenses” which concluded after calculating the result of carrying one for eight hours a day for 240 days a year, “These ratios are so close to zero that the conclusion drawn in this thesis is that there are no radiation related health hazards involved.”

So how does it handle? The lens itself makes a powerful impression on a few counts. This first is notably how small and lightweight it is. My favorite combination in normal day-to-day photography is the very sharp and well-balanced Tamron 35 f/1.8 VC on the Nikon D750. It is a combination of plastic and metal, and weighs in at 450g, or exactly 1 lb. The Mamiya-Sekor on the other hand is entirely metal, is a fast f/1.4 lens, and yet still weighs in at a mere 305g. It also looks almost diminutive in comparison.

As a manual focus lens, the focusing ring is very smooth with a fairly wide throw, and the aperture ring is pleasant with palpable and audible clicks at each half-stop. In spite of its slighter stature, it still instills a very solid feeling thanks to its all-metal body and the larger frontend glass gives it that promise of extra light and subject isolation.

Because I am not shooting with a mirrorless camera, I do not have infinity focus on it, but nor has this been a crippling hindrance in practice. The 55mm focal length isn’t really about wide-angle landscapes, and is more a shorter range portrait lens by nature. 50mm is already considered a decent starting point for headshots, losing much of the distortion that wider angle lenses cause, and the extra 5mm helps bring it down even more. Also, for reasons I cannot explain, the minimum focus distance I measured is only 30cm (one foot) instead of the 50cm described in the official specs. If this is the result of using it on a DSLR instead of a mirrorless, I’ll take it. This has the added benefit of allowing some fairly close shots with creamy background dissolution.

Wide open at f/1.4 the Mamiya Sekor 55mm F/1.4 is a bit soft, even in the center, though not criminally so. Already by f/1.7 (the half-stop click between f/1.4 and f/2) the center sharpens up enormously, and while some chronic pixel-peepers might still find reasons to object, I find it already immensely usable.

Below are a few images taken at f/1.7. These were taken in a variety of conditions, and while the edges do fall off a bit, it wasn’t a concern for the subject matter. I regularly shoot at f/1.7 and f/2, and won’t think twice about using either with this lens.

In busy backgrounds the bokeh can be a bit on the nervous side, but for the most part it is usually very smooth and enjoyable, and it can produce dreamy images combining admirable sharpness with nice isolation.

As a rule I don’t tend to worry too much about things such as contrast or colors straight out of the camera, unless they are problematic, since all my images will be filtered and undergo some light post-processing in software. Nevertheless, the colors do tend to gravitate towards a slightly warmer palette, and while contrast is only average at f/1.7, as of f/2 and higher it soon becomes good to excellent ‘out-of-the-box’. In fact, in all of the images no color was actually adjusted, and only a smidgen of contrast and some microcontrast were really added.

When I first got the Mamiya the images tended to be on the yellow side due to the yellowing the thorium causes on the glass over long periods of disuse, but this is easily corrected through UV light, and even if you don’t subject it to any special treatment, if you shoot it often enough in the day the sunlight alone will clear it up over time.

It is worth adding that there is a very respectable f/1.8 sibling, which some have claimed is equal to the 55mm F/1.4. I own both, and having both I can say that the two lenses are not closely matched. While the f/1.8 may be an excellent lens, the f/1.4 is a great one.

Though by now I have accumulated other vintage lenses sharing the same rough characteristics as this one, the Mamiya Sekor 55mm F/1.4 is still my favorite of the lot, possibly for being my first love, and is the one I keep reaching for time and time again. I heartily recommend it.

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Albert Silver

Albert Silver was born in New York, raised in Paris, and lives in Rio de Janeiro. His photography began covering chess events, such as the World Championships, and his work has featured in many of the most prominent magazines of the genre as well as books. He also works in software development, writing, translation, and teaching.

All stories by:Albert Silver
  • I have two M42 Mamiya lenses. One is 55mm, F1.4, another is 50mm F1.8. Both have yellowing of the glass. I thought both are radioactive.
    My friends helped me to measure the radioactivity level of my lenes.

    The one which is AUTO Mamiya/Sekor (DTL series) 50mm F1.8 was radioactive, the tool we used dentified thorium-232.
    Front element had 0.24 μSv/h, and rear element: 1.164 μSv/h

    However the othe, 1.4 lens was not radioactive: front element: 0.09 μSv/h, rare element: 0.09 μSv/h.

    Surprisingly another lens I had was radioactive, it was not yellow at all, the lens had this blue color in them. That is Pentacon MC auto 50/1.8. Front element: 0.14 μSv/h, rare element: 0.13 μSv/h.

    • I cannot comment on your own copy, and maybe it was a rare outlier. I can say without question my copy was quite yellow when I first got it. I still have images that confirm my memory was not playing tricks on me. You can find a very long list of tested lenses here: and will find the Mamiya listed and tested as radioactive. Cheers!

  • Very nice.

  • Great 😉
    This is a time of great reviews 😉
    Love this one.
    Images impressive.
    When we go to 50mm, mostly all lens are good, but this one has strong quality 😉
    This review is very very well made : thank you so much.

  • I believe there were at least two variations of this lens. One was 6 element and the other 7 elements. One or both perhaps Tomioka. The Zeiss Planar was a six element double-gauss lens so the Tomioka 7-element F1.4 cannot be a Zeiss Planar copy. There is a trend to call all Japanese lenses of unknown make Tomiokas. Other manufacturers besides Tomioka were used, nevertheless I think the 7-element F1.4 lens is indeed a Tomioka. The reflections seen when looking through the detached lens can be carefully counted to discern number of elements. I have this lens as well, but the f1.7 is sharper stopped down, as would be expected. This lens is best used at closest focus wide open for portraits or similar isolated foreground subjects to show its desirable characteristics of paper thin depth of field and creamy ‘bokeh’ background. No evidence of swirly ‘bokeh’ in my shots. If shooting landscapes or architecture, you would be better off using a F1.7 or slower.

  • Hi John,

    There were indeed at least two versions of the lens, but both were 7 elements in 5 groups. You may be thinking of the 55mm f/1.8 version which was indeed 6 elements in 4 groups. Please refer to:
    As to the Carl Zeiss Planar, here too you may be confusing it with the later 50mm f/1.4 version. The 55mm f/1.4 was 7 elements in 5 groups as shown in the optical design above. For more details, please feel free to consult:


  • Cheyenne Morrison July 19, 2021 at 6:51 pm

    I concur with John (above), this is indeed a lens made by Tomioka, which is indicated by the clockwise aperture blades. The lens was also rebranded as Auto Sears/Rikenon/Revuenon. I wasn’t able to find much written about the 6 and 7 lens element variants, but the 7 element version was branded as the Porst Color Reflex Auto, a very fine lens. Tomioka also produced the very rare Mamiya/Revuenon/Rikenon/Yashica ML 55mm f/1.2 aka Auto Tominon a superb lens which also used 7 elements. It was also produced for Yashica as the Yashinon DS-M 55mm F1.2.

  • Shubroto Bhattacharjee July 19, 2021 at 9:25 pm

    Eminently readable, lucid and informative review, Albert; lovely pics, too. Thank you.
    What adapter did you use to mount the Mamiya onto your D750?
    Did you input the max aperture data manually into the D750 menu?

    • I used an adapter identical to this one: This seems to be a very generic model, and I had one delivered from China for less than $2 (shipping included). This one presses the aperture pin on the rear side of the lens, essential to be able to change the aperture once mounted. As to entering aperture data into the camera, it honestly never even occurred to me. 🙂 If I take a lot of images and think the aperture important I will just make a note.

      • Shubroto Bhattacharjee July 29, 2021 at 5:41 am

        Thanks. Albert. That was very useful info.
        Just struck me that entering the max-aperture value might not be of any use, for you’d have no way of telling the Nikon meter what relative aperture you’d set. Stop-down metering would be the only one to go…
        Kudos to your adventurous spirit. Enjoy your voyage of discovery.

        • Thanks Shubroto, the adventure doesn’t stop there. As I told James via email, I just bought a Minolta X-300 and M42 adapter for it, which will take a few weeks to get here, but will also be my first film SLR. I will be documenting my efforts in detail to master it, and likely comparing with digital at the same time. It promises to be challenging and fun.

  • I would have found it far more interesting to see what the lens could do fitted on the camera it was sold with.

    • Well, maybe Albert will shoot it on that camera as well. If so, I’ll add the photos to the article.

      • While I cannot actually do this on a genuine Mamiya Sekor SLR, as the grimy leftover mentioned in the article made the garbage bin, I can still do this on a Nikon film camera easily enough, thanks to a friend. And film cameras are not sensor-dependent like modern digitals. That said, there is a challenge in obtaining film. In the United States I’m sure it’s easy unless you’re in a very isolated part of the country, but right now in Rio de Janeiro, a major metropolitan, film is simply not easily accessible. I called a store that develops and they said there is a shortage of film in Brazil, and there is a wait of a week or ten days for Fujifilm, or a month for Kodak. I’ll see what I can manage. Having never shot film (I don’t count the instant Polaroids of my teen years) it will be an experience.

  • Interesting review of a lens that doesn’t get much fanfare. I’m almost tempted to get one to supplement my Helios 44-2 and my CZJ 50mm f/2.8 Tessar, but how many 50-60mm lenses does one person need in the same lens mount? Also, I find using vintage lenses adapted to DSLRs to be not nearly as fun and satisfying as using a mirrorless camera, mostly because I know these Nikon DSLRs only have an imperfect “in-focus” light in the viewfinder as a focusing aid, compared to focus peaking. Finally, though historically more affordable due to less hype, many more reviews like this one will definitely cause prices to jump considerably for these Mamiya/Sekor lenses.

  • I have had and enjoyed a copy of this lens; the lens that currently has my attention is the Mamiya Sekor 58mm f1.7 (M42)…

    Superlative lens, with a filmic quality that hides the fact you’re shooting on a digital camera…..

  • Also branded as Sears Sekor and you should note that for people who do want infinity focus on Canon EOS or to adapter-stack to any mirrorless from that, there is a special M42 adapter made for Mamiya and Fujinon lenses because they have a ridge extending below the bottom of the screw mount plate.

  • I wrote about the need for special M42 adapter here :

  • Thank you for the nice review. I have a more recent version of te lens with rubber coating around the focus ring. It takes 52mm filters and the shortest focusing distance is 45cm. I think it has the same optical construction as your lens, but it does not seem to have Thorium glass. To put it on my M42 to Fuji adapter I had to pull out a small white metal pin on the back of the lens. I was surprised to have such good results at full opening, it is one of the best 1,4 lenses I have ever used so far.

    • how did you get the pin out of the back? I just pull it or do I have to remove the lid?

      • Hello Gérard,
        My answer may be late but as I went through this…
        I think you are talking about the SX series here.
        I have always found it a shame to deteriorate these old lenses.
        You can find adapters today that avoid this. They have a slightly raised part (silver on the example). I use this adapter successfully with Mamiya SX and Fujinon.

        Other brands surely do it with the mount of your choice.

        I really like those old Mamiya lenses and the one quoted in the article is one of my favorites.
        In the SX series, the 28mm and 135mm are also very good.

        Of course, this is only a personal opinion, I am not a professional photographer.

        Albert, nice post !!

  • After buying a Canon R Mirrorless camera a few months ago, I started experimenting with the large inventory of M-42 lenses I had from my (very) old Pentax Spotmatic days. Included in the bunch was the Mamiya/Sekor 55mm f1.4 M-42 lens you reviewed here. I agree it is a fine lens, but the Asahi Takumar 50mm f1.4 lens is equally as good with very sharp images in a more compact package. My only complaint about the Mamiya lens is that the focus ring rotation is about 300 degrees and a quick change in focus to another object is not easy to achieve. Like yours, my lens came attached to a filthy Mamiya 1000 DTL camera. This camera is kind of unique in that it had both area and spot metering capabilities. I’ve heard that Mamiya medium format camera owners wish the lenses for medium format were as well made as they were for the 35mm series.

  • There are a few things that should be clarified.
    1) The Zeiss Planar 1.4/50mm and the Tomioka 1.4/55mm (be it Yashica, Mamiya, Ricoh, Vivitar, Revue, Porst, etc etc) can be compared to one another, but it’s a loose comparison. Most 7-elements Planar-type lenses have a lot in common. Some were radioactive, some not. Some changed the type of glass during the production run of the same model. The Super Takumar 1.4/50mm is an example: the 8-elemens version is not radioactive, the successive 7-elements of the same name is radioactive, but if I remember correctly there are a few 7-elements that are not radioactive! The SMC version, the last in M42 mount, should be NON radioactive, cause it has the same optics of the SMC Pentax (PK mount), which I can personally confirm NOT being radioactive. I own both the f/1.4 and the f/1.2 versions.
    Changes in MC technology and glass types happened all the time, without being advertised to the public or even mentioned in technical data. Maybe it’s worth repeating that it wasn’t always for the better. Sometimes it was to reduce production costs, and more often to replace glass types that weren’t made anymore because they contained hazardous materials.

    2) Mamiya Sekor M42 lenses were outsourced to various optical companies. AFAIK the 50’s and 55’s were made by Tomioka, but other focals came from different manufacturers. For sure Mamiya medium format users weren’t envious of the quality of M42 lenses. Many lenses of the 645 series, most of the 67 series, and the wide angles of the 6×9 were at very high levels. Hasselblad/Zeiss and Pentax 6×7 levels, to make myself clear.

    3) I have a special liking for Tomioka made fifties. The 1.2/55mm reigns supreme, but the 1.4/55mm comes close second.
    The f/2 versions are also good, especially early 5cm models. Many people believe that the two extreme options are preferable: either very early 2/5cm versions, or late multicoated ones. I share the same opinion. Old lenses from the sixties usually have better build and beautiful bokeh. Newer MC lenses have better resistance to flare and better contrast.

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Albert Silver

Albert Silver was born in New York, raised in Paris, and lives in Rio de Janeiro. His photography began covering chess events, such as the World Championships, and his work has featured in many of the most prominent magazines of the genre as well as books. He also works in software development, writing, translation, and teaching.

All stories by:Albert Silver