- The focal length is 28 mm.
- The maximum aperture is 3.5.
- The minimum aperture is 22.
- The number of aperture blades is 6.
- The number of lenses / groups is 8/7.
- The minimum focusing distance is 0.2 m.
- Resolution center / edge - 42/20 lines per mm.
- Light transmission - 0.74.
- The working distance is 45.5 mm.
- Attachment attachments - threaded m67.
- Optics mount - A (standard adapter A / m42).
- Weight - 560 grams.
Ergonomics and design:
Mir-10A possesses excellent intuitive and classical ergonomics, the arrangement of the controls repeats the samples of the 50-60s 1, but unlike their ancestors, they are located at a greater distance from each other.
The focusing ring is wide enough to rest your fingers completely on it, the ribbing in the metal prevents slipping, although wet fingers do slip. Its incomplete rotation (from MDF to infinity) is 275°.
The diaphragm switching ring is placed on the front part, it switches smoothly without steps. The second ring, closer to the front lens, is a mechanical stop of the aperture travel, aperture presetting. If you put it in position 5.6 (or any other), the aperture ring travel will be limited to 5.6, to be precise, the aperture will work in the range from 3.5 to 5.6.
This arrangement of controls is found on all, without exception, Soviet lenses with the letter A at the end (Tair-11A, Telemar-22A, Jupiter-37A, etc.)
The main distinguishing feature of MIR-10A is the system of replaceable adapters "A" (where it is indicated in the name). It allows you to change the standard tail of the M42-A, for example, to the KP-A / N, it is simpler for the Nikon mount while maintaining the ability to focus to infinity. The tail is attached to the lens with three screws.
The Mir-10A aperture consists of six matte blades (the lowest value for A-series lenses). At all values except open 3.5 and closed 22, the petals form a swirling hexagonal star, which is unusual.
Like any other wide-angle lens Mir-10A is designed for shooting landscapes, architectural ensembles, etc. Accordingly, it is required to clamp the aperture, from 5.6 and higher. An open aperture of 3.5, although it gives an acceptable sharpness in the center, is solid soap along the field and the edge of the frame, moreover, there is no contrast. But the color rendition is as it is. Therefore, the emphasis is on 5.6 and up.
Low light transmittance makes its contribution, at equal diaphragms Mir-10A is darker than more modern counterparts by a third of a stop. Mir-1 has a similar problem.
In architectural photography, perspective distortion can be observed. The peculiarity of wide-angle lenses - in this case, Mir-10 from 4 meters at aperture 5.6 already gives infinity, in most cases there is practically no need to focus.
Although the lens gives acceptable sharpness in the center of the frame, the contrast appears at apertures of 5.6 and higher, as does the field sharpness. Mir-10A is excessively large and heavy, with the same dimensions the Japanese brands produced more aperture 28mm short focus 2.0-2.8. Mir-10A is often called the most unsuccessful optical wide-angle in the series of "A" lenses. I will add that Mir-10 is the most not expressive wide-angle in the USSR.
Of the noticeable advantages, the lens has a non-killable construct and a universal lens mount "A".