Pekka Buttler, 08/2026
Specifications
The table below summarizes the lens’ key specifications (Measurements based on pictured sample):
| Brand: | Yashica | Lens name | Auto Yashinon 1:2 f=5cm |
| Focal length(s)1 | 50 mm | Angle-of-view2 | 46 ° |
| Maximum Aperture | f/2 | In Production | 1961–mid 60s |
| Lens mounts | M42 | Subfamily (if applicable) | n/a |
| Length3 | 34,4 mm | Diameter4 | 56,0 mm |
| Filter ring diameter | 46 mm | Weight | 232 grams |
| Lens element count | 6 | Lens group count | 4 |
| Aperture blades (S/R/C)5 | 6 S | Focus throw | 245 ° |
| Minimum focusing distance | 55 cms | Maximum magnification | 1:9,1 |
| Has manual aperture ring | YES | Has Manual focus ring | YES |
| Aperture mechanism type: | Semi-automatic | Aperture click stops:6 | 2-2.8-4-5.6-8-11-16 |
Further notes:
• Between the short-lived Yashica Pentamatic mount (1959-61) and the relatively illustrious Contax-Yashica mount (1975->), Yashica used a standard M42 mount for its cameras and lenses.
• The Yashica Auto Yashinon 50 mm f/2 was introduced in 1961 and was offered as standard/kit lens with a wide range of early Yashica M42 camera bodies.
• The lens’ rearmost structures protrude a fair bit into the M42 mount, so there might be some M42 bodies where the mirror runs into conflict with the rear lens (especially when focused at infinity).
• This lens uses a semi-automatic aperture, meaning that while the body can stop down the lens in time for the shutter to fire, the aperture does not automatically open back up again. Instead, it needs to be cocked by the photographer swinging the lever near the lens’ base.
• In terms of adapted photography, semi-automatic lenses are unproblematic, as – so long the photographer does not cock the aperture – the diaphragm obediently follows the aperture ring’s commands.
• This lens was replaced – likely in the mid 60s – by the Yashica YASHINON-DX 50 mm f/2. See Yashica Company profile for details.
Versions
JAPB has no information of a significant redesign having happened during the life of this lens.
Adapting
If you want to natively mount this lens you need to find a functioning m42 mount film camera. Luckily that should be relatively easy as m42 bodies were produced in their millions and most of them lack features that are especially likely to have deteriorated to the point of making the entire camera inoperable.
Adapting this lens to a mirrorless, full-frame digital camera is a breeze thanks to the lens having full manual controls (aperture ring, focus ring). You simply need a dumb adapter from M42 to your mirrorless system, but be mindful of that your adapter should have an extra flange to actuate the aperture stop-down pin (otherwise you cannot stop down the lens).
Due to the medium flange focal distance used by the m42 mount (45,46 mm), whether you can adapt this lens to dSLR/SLR mounts depends on which dSLR mount: Canon EF, Four Thirds, Minolta/Sony A and Pentax K can mount m42 lenses using a simple adapter ring. Nikon F on the other hand is not as problem-free, and – to retain anything near infinity focus – the adapter will necessitate corrective optics. In all cases, your camera will work only in stop-down metering.
Footnotes
- Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
- Picture angle is given in degrees (based on manufacturers’ specs) and concerns the diagonal picture angle. Rule of thumb:
> 90 ° ==> Ultra-wide-angle
70–90 ° ==> Wide-angle
50–70 ° ==> Moderate wide-angle
40–50 ° ==> ‘Standard’ or ‘normal’ lens
20–40 ° ==> Short tele lens
10-20 ° ==> Tele lens
5-10 ° ==> Long tele lens
< 5 ° ==> Ultra-tele lens ↩︎ - Length is given from the mount flange to the front of lens at infinity. ↩︎
- Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
- S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
- Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎