According provided by lens SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. many thanks to the store FOCUSFILM (subscribe to INSTAGRAM). There you can find many interesting film cameras and manual lenses.

SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. increase.
In short
SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. - a classic manual fifty kopeck piece from a bygone era. The first PENTAX in the 50/2 class. Later it was updated to version SMC PENTAX-A 1:2 50mm, after which the Pentax 50/2 lens series was no longer developed and was displaced by other similar fifty dollars of the 50/1.7 class.
Nowadays SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. First of all, it is interesting for its very compact size and availability in the secondary market. This is a good middling among other similar inexpensive fifty dollars of the past era. At F / 2 resolution is good.
In fact, SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. is the most 'simple' lens among all the other Takumar/Pentax fifty dollars. He has the weakest aperture, few aperture blades, a rather primitive 5/5 optical design, and it is made in Taiwan.
All major versions of similar lenses Asahi Opt. Co., Takumar / Pentax:
1.2/50
- SMC PENTAX 1: 1.2 / 50 ASAHI OPT. CO., JAPAN (7/6, 20947, 1975-1984)
- SMC PENTAX-A 1: 1.2 50mm + black / silver 'SPECIAL' (7/6, 20987, 1984-2004)
1.4/50
- Super takumar 1: 1.4 / 50 Asahi Opt. Co., Lens made in Japan (8/6, 358, 1964-1966)
- Super takumar 1: 1.4 / 50 Asahi Opt. Co. Lens made in japan (7/6, 37800, 1965-1971)
- Super-Multi Coated TAKUMAR 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 37902, 1971-1972)
- SMC TAKUMAR 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 37908, 1972-1975)
- SMC PENTAX 1: 1.4 / 50 ASAHI OPT. CO., JAPAN (7/6, 20847, 1975-1977)
- SMC PENTAX-M 1: 1.4 50mm ASAHI OPT. CO., JAPAN (7/6, 20867, 1977-1984)
- SMC PENTAX-A 1: 1.4 50mm (7/6, 20887, 1984-1989)
- SMC PENTAX-F 1: 1.4 50mm (7/6, 20827, 1987-1991)
- SMC PENTAX-FA 1: 1.4 50mm (7/6, 20817, 1991-2023)
- HD PENTAX-D FA * 1: 1.4 50mm SDM AW (15/9, 21260, 2018->)
- SMC PENTAX-FA 1:1.4 50mm Classic (7/6, 2023->)
- HD PENTAX-FA 1: 1.4 50mm (7/6, 2023->)
1.4/55
- SMC PENTAX-DA * 1:1.4 55mm SDM (-, 9/8, 21790, 2008->)
1.7/50
- SMC PENTAX-M 1: 1.7 50mm ASAHI OPT. CO., JAPAN (6/5, 20877, 1977-1984)
- SMC PENTAX-A 1: 1.7 50mm (6/5, 20897, 1984-1989)
- SMC PENTAX-F 1: 1.7 50mm (6/5, 20837, 1987-1991)
- SMC PENTAX-FA 1: 1.7 50mm (6/5, 20907, 1991-2004)
1.8/50
- SMC PENTAX-DA 1: 1.8 50mm (6/5, 22177, 2012->)
2/50
- SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. (5/5, 20677, 1979-1985)
- SMC PENTAX-A 1: 2 50mm (5/5, 20697, 1985-1998)
1.8/55
- Auto-takumar 1: 1.8 / 55 ASAHI OPT. CO. Lens made in japan (6/5, 1958-1962)
- Super takumar 1: 1.8 / 55 Asahi Opt. Co. Lens made in japan (6/5, 37106, 1965-1971)
- Super-Multi Coated TAKUMAR 1: 1.8 / 55 ASAHI OPT. CO., JAPAN (6/5, 37104, 1971-1972)
- SMC TAKUMAR 1: 1.8 / 55 ASAHI OPT. CO., JAPAN (6/5, 37108, 1972-1975)
2/55
- Auto-takumar 1: 2 f = 55mm Asahi Opt. Co., Japan (6/5, 34100, 1958-1959)
- Super takumar 1: 2 / 55 Asahi Opt. Co. Lens made in japan (6/5, 37103, 1962-1973)
- 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:
- takumar 1: 2 f = 58mm (6/4, 1957-1958, M42)
- takumar 1: 2.4 f = 58mm (5/3, 1957-1958, M42)
- Auto-takumar 1: 1.9 f = 55mm (6/5, 1958-1959, M42)
- 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).
Main technical characteristics of SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO.:
Review Instance Name | SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. |
Basic properties |
|
Front Filter Diameter | 49 mm, metal thread for filters |
Focal length | 50 mm |
Zoom ratio | 1 X (this is a fixed lens, it does not have a zoom). |
Designed by | for film cameras with a frame size of 24 x 36 |
Number of aperture blades | 6 petals. Petals dark matte
At f / 2.8, the aperture blades form a hole with small notches |
Tags |
|
Diaphragm | from f / 2 to f / 22.
The lens has an aperture control ring. There are marks on the ring for F/2, 2.8, 4, 5.6, 8, 11, 16, 22. One additional value can be set between each pair of numbers (except F/2->F2.8, F/11->F /16 and F/16->F/22). |
MDF | 0.45 meters, maximum magnification ratio 1:6.7 |
The weight | 140 grams (measured) |
Optical design | 5 elements in 5 groups
|
Lens hood | Threaded, screwed into the front filter thread |
Manufacturer country | MADE IN TAIWAN (inscription on the body, the lens is made in Taiwan) |
Period | 1979-1985. Later replaced by SMC PENTAX-A 1:2 50mm (1985-1998). |
Price | About $ 50 for used option. Current prices can be look at EBAY.
Prices for modern Pentax lenses can be viewed at E-Catalog. |
The remaining series of similar Takumar / Pentax lenses use more advanced optical designs with a 6/5 and 7/6 layout. The 5/5 scheme is the most primitive and rarely used by big-name brands.
Assembling, focusing
SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. well assembled. Separately, it is worth noting the small size and diameter of the light filter by 49 mm.
Interestingly: The inscription 'MADE IN TAIWAN' ('Made in Taiwan') is hidden on the retractable rim of the lens barrel (on the trunk). It cannot be seen until you focus on the MDF, but it is still partially obscured by the protruding lens barrel. The rest of these lenses were made exclusively in Japan. Usually next to 'ASAHI OPTICAL CO.' the word 'JAPAN' always appears. In the case of SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. one gets the feeling that the manufacturer was ashamed of the inscription 'MADE IN TAIWAN' and added it in the most inconspicuous place.
The focus ring has an anti-slip insert made of very rough material, rotates approximately 225 degrees (5/8 of a full turn). The course of the ring is very smooth, oily, pleasant. During focusing, the front retractable part of the body does not rotate. Focusing occurs by moving the entire lens block.
The lens uses a Pentax K mount and can be mounted on any modern Pentax digital SLR camera with a K mount.
Sample photos (Full Frame)
The pictures in the gallery were taken with a camera Canon EOS-1 Ds Mark II (Full Frame, 17 MP) and adapter Pentax K -> Canon EF. Photos in JPEG format from the camera without processing. A CPC PHASE 2 49mm SKY light filter was used everywhere.
RAW '.CR2' original photos can be download / watch this link (15 photos).

SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. and 7Artisans 50 / 0.95 (for APS-C, 7Artisans FireFly series, for Sony E mount)
Sample photos (APS-C)
All photos in the review are shown without processing. Photos on a cropped camera were prepared by a photographer Natalia (Instagram). Camera used Sony NEX-6 (16 MP Sony Exmor APS-C HD CMOS sensor) and adapter FOTGA PENTAX K -> SONY E/NEX. All photos are in JPEG format, straight from the camera.
Original JPEG '.JPG' photos can be download / watch this link (15 photos).

SMC PENTAX-M 1:2 50mm ASAHI OPTICAL CO. and 7Artisans 50 / 0.95 (for APS-C, 7Artisans FireFly series, for Sony E mount)
Comments on this post do not require registration. Anyone can leave a comment. Lenses and promotions on them look at Moyo.ua.
Material prepared Arkady Shapoval. Training/Consultations | Youtube | Facebook | Instagram | Twitter | Telegram.
Why is 5/5 suddenly a “primitive” scheme? It turns out 4/3 - generally sucks?
Something I do not know fifty dollars with 4/3. And yes, in the general case, if we go down to the triplet, then more and more we go into primitive (old) schemes.
Compared, for example, with the same 6/5 that Pentax 50 / 1,7 and many other Takumars / Pentaxes have, they pasted the rear elements and simplified the scheme. This also affected the aperture ratio with acceptable optical performance.
Among all Takumars / Pentaxes, this 5/5 is the simplest (there is, of course, the renegade Takumar 1: 2.4 f = 58mm, but he is little known)
Four lenses in three groups. Scheme "Tessar". Poltinikov - at least a dime a dozen. Unless there is a limitation in aperture ratio
I think we are talking about fifty dollars class 50/2.
Yes, I got it, thanks
The layout of the five-lens planar is a very compromise for a lens with a 45° field of view, f/2, a 36x24 frame and an elongated rear segment. Of course, sticking lenses, the use of new types of glass made it possible to make this lens lighter and better than the ancient Soviet Vega-3 50 / 2.8, but just like Vega-3 loses to the banal Helios-44, this pentax 50/2 loses to more complex 50 / 1.8 and 50 / 1.4 at equal apertures.
And the 4/3 scheme (“tessar”) is not used at all in class 50/2 optics. Although I have seen a 50/2.2 triplet...
Personally, my opinion is that a 50/2.8 tessar is better than a comatose 50/2 (or 50/2.8) five-lens planar.
Ah, I sort of get it. Thank you
"MADE IN TAIWAN" made in Taiwan! Not surprising though, you don't seem to know your country of residence either.
Fixed
Just a good lens. Infinity is really “soft”, but quite)
I sometimes use the SMC PENTAX-A 1: 2 50mm version, through an adapter to the Nikon Z7 - a typical planar box, but after modern lenses it's cool.
So in Taiwan or Thailand, Arkady? x)
Fixed
For erudition: resolution refers to light-sensitive materials and light receivers. Lenses have resolving power.
Now the question is: how much do pentax A 50 / 1,2 pentax 50 / 1,7 differ in quality. Thanks in advance, best regards.
Hello. There is exactly the same outwardly 50 2.0 lens for Pentax k. The only caveat is that the model is not indicated on the front ring. All that is: Multicoated (in red) f=50mm (in green) 1:2.0 (in white) No.XXXXXXXX 49 (in green) (thread diameter). What is this animal? Some kind of fake?
Attach a photo
Hi,
here is the link…
https://www.ebay.com/itm/364094484943
here it is
here it is
here it is
here it is