Overview of ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm. UPDATE 2.0

According provided by ASAHI OPT lens. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm and photos from it, many thanks to Ivan Koronevsky.



In short

SMC PENTAX-M 1: 1.7 50mm ASAHI OPT. CO., JAPAN is a good classic fifty from the PENTAX-M lens series. It differs from the mass of other fifty dollars in a slightly increased relative aperture (F / 1.7 vs F / 1.8). Highly appreciated for excellent value for money, especially among Pentax optics enthusiasts.



Main specifications of ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm:

Review Instance Name ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm 4093607
Basic properties
  • SMC (Super Multi Coated) - special super-multi coated optics
  • M - compact lens for compact cameras, like Pentax MX. Without full automatic iris control.
  • Bayonet mount Pentax K
  • manual focus only.
  • aperture control ringas well as semi-automatic iris control using the ring aperture and the corresponding camera mechanism that has it.
  • lens suitable for full-frame cameras
  • metal casecompact size
Front Filter Diameter 49 mm, metal thread for filters
Focal length 50 mm

On Pentax cameras with APS-C sensor EGF lens equals 75mm

Zoom ratio 1 x
Designed by for film cameras with a frame size of 24 x 36 mm
Number of aperture blades 6 petals

At an intermediate value between F / 2 and F / 4, the diaphragm blades form a hole with pronounced notches (see photo of the lens in the review below), the hole at the same time looks like a circular saw. For F / 4-F / 22 values, a hole in the shape of a regular hexagon

  • focus distance scale in meters and feet
  • depth of field scale for F / 4, 8, 16, 22 explicitly, for F / 5.6, 11 only dashes
  • infrared label
  • label for attaching the lens.
Diaphragm from F / 1.7 to F / 22. The lens has an aperture control ring. There are marks on the ring for F / 1.7, 2.8, 4, 5.6, 8, 11, 16, 22. You can set one additional value between each pair of numbers (except between F / 16 and F / 22). The diaphragm ring rotates with clicks.
MDF 0.45 m, maximum magnification ratio 1: 6.7.
The weight November 185, XNUMX
Optical design 6 elements in 5 groups

ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mmThe lens does not use special optical elements in its optical design. The same optical scheme is used by many other lenses.

Lens hood Threaded, screwed into the front filter thread
Manufacturer country LENS MADE IN JAPAN (lens made in Japan).
Period From 1977 to 1984. In 1979 it was supplemented by a similar SMC PENTAX-M 1: 2 50mm ASAHI OPT lens. CO., JAPAN. In 1984 was replaced by PENTAX-A 1: 1.7 50mm
Price About 50 cu for used option.

Prices for modern Pentax lenses can be viewed here.

SMC PENTAX-M 50 / 1.7 is well built. The focusing ring has a rubberized insert and rotates approximately 225 degrees. The movement of the ring is very smooth. Almost all old lenses - fifty and fifty - are from ASAHI OPT. CO., JAPAN have an exceptionally pleasant focusing ring travel. The front extension body does not rotate during focusing. Focusing occurs by moving the entire lens unit.

Aperture notches at F / 2 for ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm

Aperture notches at F / 2 for ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm

Sample Photos

Important: on a Canon EOS 5D I tried to use the SMC PENTAX-M 50 / 1.7 with the usual adapter PENTAX K - CANON EOSwhich I usually had no problem with. But in this case, the rear lip of the SMC PENTAX-M 50 / 1.7 mount clings to the mirror of a full-frame Canon EOS 5D camera. To get at least some pictures with this lens, I used the thinnest 14 mm macro ring from my AF macro kit for Canon EF / EF-S... As a result, the focusing distance during focusing 'to infinity' was 35 cm (almost MDF, equal to 45 cm, the distance was measured from the subject to the focal plane). Most likely, there will be no problems on cropped Canon EOS cameras with such an adapter.

Photos taken using RAW ('.CR2') file conversion with Canon original utility Digital Photo Pprofessional 4 (Canon DPP) Some photos were taken using a polarizing filter. GREEN.L CPL 52mm and additional adapter ring 49/52 mm... Original photos in RAW / '. CR2' format can be downloaded from this link. One photo at 500px here.

UPDATE 1: more examples of photos from Ivan, the owner of this lens, that were obtained using Pentax Kr.

UPDATE 2: Alexey Ovoshchnikov I also decided to supplement the review with information and sample photos. Below is its text:

This is my addition to the review of Arcadia, I added a full-frame photo with the ability to focus on infinity. Now you can see how portrait frames come out using this wonderful optics. The lens pleased with a very small vignetting even at a fully open aperture and good sharpness at the edges of the frame. Optically, the lens is very suitable for portraiture. Attention! There is one minus! For use on a full-frame Canon camera, the lens must be slightly redone! The alteration consists in removing the rear plastic by unscrewing the three mounting screws from the bayonet mount side. After removing the plastic, the washer and pressure bracket are also removed. In fact, they themselves fall out after removing the plastic plug as nothing else holds them. As such, you can try to use this lens on your Canon full-frame camera (of course, using an adapter PENTAX K - CANON EOS).

However, this is not a complete lens conversion for full frame use. Pentax lenses have one important technological element at the back (aperture control lever). Unfortunately, its presence makes it difficult to use the lens on a full Canon frame even after rework. The mirror is still not fully raised and the bottom of the frame is slightly darkened. I noticed this only after the photo session and was glad that nothing had happened to the camera mirror. I was surprised by this fact, since the other two lenses for the Pentax system work wonderfully without any problems on the same camera (of course after the alteration described above).

Sample photos on Canon EOS 6D:

Sample photos on Pentax Kx:

All major versions of similar lenses Asahi Opt. Co., Takumar / Pentax:


  1. SMC PENTAX 1: 1.2 / 50 ASAHI OPT. CO., JAPAN (7/6, 20947, 1975-1984)
  2. SMC PENTAX-A 1: 1.2 50mm + black / silver 'SPECIAL' (7/6, 20987, 1984-2004)


  1. Super takumar 1: 1.4 / 50 Asahi Opt. Co., Lens made in Japan (8/6, 358, 1964-1966)
  2. Super takumar 1: 1.4 / 50 Asahi Opt. Co. Lens made in japan (7/6, 37800, 1965-1971)
  3. Super-Multi Coated TAKUMAR 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 37902, 1971-1972)
  4. SMC TAKUMAR 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 37908, 1972-1975)
  5. SMC PENTAX 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 20847, 1975-1977)
  6. SMC PENTAX-M 1: 1.4 50mm ASAHI OPT. CO., JAPAN (7/6, 20867, 1977-1984)
  7. SMC PENTAX-A 1: 1.4 50mm (7/6, 20887, 1984-1989)
  8. SMC PENTAX-F 1: 1.4 50mm (7/6, 20827, 1987-1991)
  9. SMC PENTAX-FA 1: 1.4 50mm (7/6, 20817, 1991-2023)
  10. HD PENTAX-D FA * 1: 1.4 50mm SDM AW (15/9, 21260, 2018->)
  11. SMC PENTAX-FA 1:1.4 50mm Classic (7/6, 2023->)
  12. HD PENTAX-FA 1: 1.4 50mm (7/6, 2023->)


  1. SMC PENTAX-DA * 1:1.4 55mm SDM (-, 9/8, 21790, 2008->)


  1. SMC PENTAX-M 1: 1.7 50mm ASAHI OPT. CO., JAPAN (6/5, 20877, 1977-1984)
  2. SMC PENTAX-A 1: 1.7 50mm (6/5, 20897, 1984-1989)
  3. SMC PENTAX-F 1: 1.7 50mm (6/5, 20837, 1987-1991)
  4. SMC PENTAX-FA 1: 1.7 50mm (6/5, 20907, 1991-2004)


  1. SMC PENTAX-DA 1: 1.8 50mm (6/5, 22177, 2012->)


  1. SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. (5/5, 20677, 1979-1985)
  2. SMC PENTAX-A 1: 2 50mm (5/5, 20697, 1985-1998)


  1. Auto-takumar 1: 1.8 / 55 ASAHI OPT. CO. Lens made in japan (6/5, 1958-1962)
  2. Super takumar 1: 1.8 / 55 Asahi Opt. Co. Lens made in japan (6/5, 37106, 1965-1971)
  3. Super-Multi Coated TAKUMAR 1: 1.8 / 55 ASAHI OPT. CO., JAPAN (6/5, 37104, 1971-1972)
  4. SMC TAKUMAR 1: 1.8 / 55 ASAHI OPT. CO., JAPAN (6/5, 37108, 1972-1975)


  1. Auto-takumar 1: 2 f = 55mm Asahi Opt. Co., Japan (6/5, 34100, 1958-1959)
  2. Super takumar 1: 2 / 55 Asahi Opt. Co. Lens made in japan (6/5, 37103, 1962-1973)
  3. SMC TAKUMAR 1: 2 / 55 ASAHI OPT. CO., JAPAN (6/5, 37109, 1973-1975)

black-silver 2/58, 2.4/58, 1.9/55, 2.2/55:

  1. takumar 1: 2 f = 58mm (6/4, 1957-1958, M42)
  2. takumar 1: 2.4 f = 58mm (5/3, 1957-1958, M42)
  3. Auto-takumar 1: 1.9 f = 55mm (6/5, 1958-1959, M42)
  4. Auto-takumar 1:2.2/55 (6/5, 1961-1963, M42)

The names of the lenses in this list correspond exactly to the inscription with the lens name near the front lens (except for the serial number).



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Material prepared Arkady Shapoval. Training/Consultations | Youtube | Facebook | Instagram | Twitter | Telegram.

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Comments: 33, on the topic: Overview of the ASAHI OPT. CO., JAPAN SMC PENTAX-M 1: 1.7 50mm. UPDATE 2.0

  • Subscriber

    Photos are wonderful !!!

  • Vladimir

    Good sharpness. But wait a photo from Pentax.

    • Michael

      Photos from the pentax are already in the article

    • German

      Thanks for the review guys! Great color, very vibrant. The cyclicle sometimes spoils the background, but taking into account age, it’s very good, I liked it.

  • Sergei

    Great fifty dollars for ridiculous money even in modern times. Pentax K 50 / 1.4 itself is slightly larger in size and aperture.

  • Н

    5d is still good

  • Igor

    Thank you.
    Good review.

    Ideally get a photo with ff from pentax.

    It would also be nice to add the same plot to each review - a scene with a set of repeating elements (toys, felt-tip pens, etc.)

    • koba

      I also wrote about this a month ago - full-frame lenses need to be tested on a full frame, and it's just wonderful that Arkady managed to return the Canon 5D, he makes all subsequent ones in color and picture. Now you need to make some scene at home and that's it, and always add the photo of this scene at all apertures to the overview, and it is better to add a resolution scale there, this is nothing. The quality of the reviews and, most importantly, their reliability in the technical part will increase markedly. It is a pity that this has not happened so far ... By the way, this lens has always been famous for its quality and here it also showed itself ...

  • German

    Yes, I wanted to know from gentlemen-pentaxists: does this white mark on the penultimate image of the lens glow at night? Thanks!

    • anonym

      No, it’s for the convenience of removing the carcass from the carcass

      • Arkady Shapoval

        Now Nikon also has a white convex round-shaped circle on new G-lenses.

        • Dmitriy

          Arkady please help with the choice of manual optics (not the USSR) for Nikon crop, already confused, a lot of good))))

          • Dmitriy

            Aperture 1.2 or 1.4 from 50mm for portraits

            • Carl Zeiss

              1,2 this for him, in my opinion, will be too much. Such glasses are the destiny of the pros. You need to come to them. Such people will not ask anyone for glass tips.
              But 1,7-1,8 it will be the most for him. The glass is predictable, with a good pattern and drawable bokeh. Acceptable for the price.

            • Arkady Shapoval

              Need a budget, it is desirable to describe your experience and the camera with which you will be used.

    • anonym

      The owners of thorium takumaras glow at night mostly ... they usually burn out in the morning. Then through the resize and again in the usual circle. The owners of 1.2, as on old fl kakh - usually a pro, as one German boob wrote here - usually come to this after 1.7-1.8 - they seem to enjoy the very process of melting ... And the rhomboids of the circles basically scare away demons. Also at night. Something like that, yak, I'm reason.

  • Denis

    Good lens, I have one)

  • Vyacheslav

    some standard pictures without a pronounced character .. just a good lens, but no more ..

    • Paul


      • reader

        and what are then outstanding among fifty dollars?

        • Alex

          Helios 44? :)

  • SashOK

    I wonder how this lens behaves on a full-frame Nikon? Also need troubles with alterations, or will it be with an adapter?

    • Arkady Shapoval

      Penton on Nikon does not get with the usual adapter. A lens adapter is not desirable.

  • Carl Zeiss

    This old glass, which costs less than a hundred dollars, can easily make most of the modern plastic branded "buckets" from the picture, which cost more than a thousand dollars.

  • Alex

    I wonder how this stuff will be on my film EOS 66

  • Fedorov Andrey

    Interestingly, is it radioactive? Does it have thorium glasses with a background?

  • Igor

    Good day. There is one caveat with this lens. Some lenses purchased in Japan have a drawback - the adhesive layer becomes cloudy in the bonding of the lenses. You can shoot with this lens with subsequent processing of the images through a photo editor. With a backlight, it is practically impossible to shoot anything.

  • Alexey

    Can you please tell me if this glass will fit the Fujifilm x-e2 mirrorless camera ???
    Will there be any problems with work, focusing at infinity and will manual aperture control work ???
    Thank you very much for the answers.

    • Andrei

      Looking at the photo of the lens and the description of its characteristics on the plate, what guesses do you have about the aperture setting?

    • Michael

      There will be no

      • Michael

        In the sense of problems, there will be no))

        • Andrei

          You will disaccustom a person to think in this way.

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