35KP-1.8 / 100 (MMZ named after Vavilov). Review of the projection lens adapted in a two-aperture version from the reader Radozhiva.

Material 35KP-1.8 / 100 specially for Radozhiva prepared Rodion Eshmakov (instagram).

In the 1980s, at the Minsk plant named after I. Vavilov, a diverse line of 35KP cinema projection optics was produced, including classic planars (6 lenses in 4 groups) with focal lengths of 85 and 100 mm with aperture F / 1.8 and split six-lens Planars with focal lengths of 120 (6/6) and 140 (6/5) mm at aperture of F / 1.8. In addition to them, four-lens aplanats of the KO type with focal lengths of 120 (aka - KO-120M) and 140 mm (KO-140M) and the same aperture, which introduces confusion in the notation to this day.

At the same time, completely different lenses with more diverse and progressive optical designs (glued six- and seven-lens variations of planars) were produced at the LOMO and IPZ factories (Izyum, Ukraine) under similar names 35KP / OKP.

In other words, the lenses produced by MMZ are the last of the classic six-lens planars of the 6/4 design produced in the USSR. We can say that these are "overclocked" versions of the predecessor PO50x-1 lenses, but in reality everything is not so simple.

All projection lenses of this series manufactured by MMZ were intended for 35 mm film (as the name suggests) and had a body diameter of 62,5 mm (some LOMO OKP lenses were as much as 82,5 mm in diameter even with a FR of 90 mm), due to which they have sane dimensions of the body and enjoy the attention of amateur photographers.

This article presents the 35KP-1,8 / 100 lens, upgraded for use with modern cameras. A feature of this specimen, in addition to the basic adaptation procedure, is the presence of a second aperture, which serves to control vignetting and the nature of the background blurring of the image.

Specifications:

Optical design - 6 lenses in 6 groups (Planar);
Focal length - 100 mm;
Geometric relative aperture - 1: 1,8 (increased to 1: 1,7 during modernization);
Light transmission coefficient - 0,82;
Landing diameter - 62,5 mm;
Lens block weight - 0,8 kg;
Features - a projection lens, does not have a diaphragm and a focusing mechanism.
Passport of this copy in PDF: passport reference

Design and adaptation

The lens is almost a kilogram aluminum lens unit. Unlike similar optics from other factories, the lenses of MMZ lenses are not rolled into aluminum pancakes. Such a nuance requires more care when assembling and disassembling these lenses: for example, it took a lot of work for me to install a huge front glue in its place. 35KP-1,8 / 120.

Representatives of this line of projection lenses have a much smaller internal diameter of the lens unit body than RO50x-1 and Zh-xx lenses, which is again dictated by the avoidance of bulk assembly. And this introduces huge difficulties associated with the installation of the diaphragm in these lenses: irises with a large aperture are required (in this case, my favorite fourteen-petal 36 mm were enough, but close to each other) and a small outer diameter. I had to grind the aperture barrel from the outside so that it could be installed inside the lens. Most likely, this approach will not work at all for adapting lenses with long focal lengths, since even larger apertures will be required, which cannot be placed inside.

To compensate for the lens distance during the installation of the diaphragm, it was necessary to order the manufacture of an additional aluminum gasket.

During adaptation, the front slotted nut was replaced by an easily removable ring with a thread for 72 mm filters - it would be nice to wear a polarik on such a lens. A feature of this part was its much larger inner diameter compared to the factory one: this made it possible to increase the working area of ​​the front lens and added another 12% aperture to the lens. In total, we have a 100 / 1.7 lens.

To focus the lens unit, a factory M65-M65 helicoid with a stroke of as much as 55 mm was used - the minimum focusing distance is only 0.4 meters! At a focal length of 100 mm, this provides a scale of ~ 1: 2.

The thread pitch is a little too small for such a focal length - from infinity to MDF, you need to make more than one revolution. But such a helicoid can provide high smoothness and focusing accuracy, which is important, for example, for users of SLR cameras.

This 35KP has an impressive back focal length. After removing the excess metal from the body behind the rear lens, the cut was more than enough to use a two-aperture layout (it was also enough for compatibility with Nikon cameras). Therefore, the lens was equipped with a second, lens aperture. This option greatly expands the capabilities of the lens: the second aperture is able to improve the contrast of the image (especially on the crop), add a "dramatic vignette" or make the bokeh more swirling.

However, it should be noted that Minsk 35KP lenses with FD> 100 mm have geometric vignetting noticeable in the full frame: the front group of lenses is noticeably larger than the back one, which is done to maintain the 62,5 mm bore diameter and reduce the weight and size parameters. On a full frame, the second aperture works especially effectively at ~ F / 2.5.

Of course, all of the above tuning affected the dimensions and weight of the lens: it is much larger than the adapted PO500-1 and even a similar two-aperture PO501-1. W-53 in comparison with him, quite a baby. However, this 35KP is larger in both aperture and FR.

Unlike LOMO lenses, the MMZ optics have pink-violet anti-reflection coating. Apparently, the optical scheme did not do without lead glasses: the lens is very yellow in transmission.

This lens turned out to be much more difficult to adapt than the usual PO50x-1. However, it is extremely interesting for its extreme optical parameters and the ability to work in a two-aperture version with SLR cameras.

Optical quality

The 35KP 100 / 1.7 with a third stop aperture higher than that of the PO500-1 100/2, turned out to be a better quality lens: the level of aberrations at F / 1.7 is not higher than that of PO501-1 at F / 2. With equal apertures, the Minsk lens looks even better. Although the overall picture at F / 1.7-F / 2.5 is soft due to spherical aberration, a coma is noticeable at the edge of the frame and rather strong longitudinal chromatic aberration - the optical scheme is working at its limit. Need better? Either more lenses, or stick the existing ones.

At F / 2.8, the lens becomes as good as the Zh-53 at F / 2 - and this is not surprising: under these conditions they have equal absolute apertures (35 mm). Strong aberrations of a simple 6/4 planar at ~ F / 2 caused the film industry to abandon the massive OKS1-100-1 100/2 lens in favor of the more compact OKS2-100-1 100 / 2.8. However, for artistic photography, the presence of aperture flavored with aberrations is very useful: with the help of an aperture diaphragm, you can greatly change the nature of the image (the so-called plasticity of the picture) by varying the aberrations. By connecting the second diaphragm to work, you can completely get a picture taken as if with a completely different lens.

35KP 100 / 1.7 often takes the color rendition into the yellow-green area. Its huge front lens also attracts various hares, rainbows and other artifacts. On the other hand, overall image contrast is generally good. Especially after matte blackening of lens and pre-lens parts according to the results of the first shooting.

Definitely, this lens occupies a worthy place among the classic 6/4 planars: with an absolute aperture larger than that of Helios-40, it provides good image quality even at open aperture with the recognizable good old planar pattern.

Below are sample images taken with a full-frame Sony A7s camera (shooting in RAW, processing in Imaging Edge).

All reviews of film projection and filming lenses:

1. RO3-3M 2/50
2. RO2-2M 75/2
3. LOMO RO501-1 F = 100 1: 2
4. PO 500-1 F9 CM. 1: 2 P
5. LOMO RO500-1 F = 90 1: 2
6. LENKINAP RO500-1 F = 9cm 1: 2 P
7. LOMO RO506-1 F = 80 1: 2
8. ЛЭТИ-60/60М F=92 1:2
9. 2/92
10. F = 92 1: 2
11. 16KP-1,4 / 65
12. 35KP-1,8 / 65
13. 35KP-1,8 / 70
14. 35KP-1,8 / 75
15. 35KP-1,8 / 85
16. 35KP-1.8 / 100
17. 35KP-1.8 / 120
18. 35KP-1,8 / 120 (with aperture)
19. LOMO P-5 F = 90 1: 2
20. LOMO P-5 F = 100 1: 2
21. LOMO P-6M F=12cm 1:1.6
22. LENKINAP OKS1A-75-1 F=75 1:2 P
23. LOMO OKS1-22-1 F = 22 1: 2.8
24. ЛОМО ОКС1-40-1 40/2.5
25. LOMO OKS1-300-1 F = 300 1: 3.5
26. LOMO OKS11-35-1 F = 35 1: 2
27. LOMO W-53 F = 75 1: 2
28. LOMO W-54 F = 85 1: 2
29. LOMO OKP4-80-1 F=80 1:1,8
30. LOMO OKP8-90-1 F=90 1:2
31. ОКП-6-70-1 F=70 1:1,8
32. Tair-41 50/2
33. KO-120 1: 2,1 120mm
34. KO-90 1: 1,9 F = 9cm
35. KO-120M 1: 1.8 F = 120mm
36. KO-120M 120 / 1.8 with a diaphragm and helicoid
37. KO-120 1: 2.1 F = 12cm
38. GOZ “KO-140” 1:2,2 F–14cm
39. Vega-9 2,1 / 50
40. MP RSFSR GLAVOCHTEKHPROM PLANT №6 ★ F=7.7cm ★
41. MSO USSR SSD UPP-1 ★ KHARKIV ★ F-7 CM ★
42. Schneider Super Cinelux 70/2
43. Meopta Meostigmat 90/2
44. Meopta Meostigmat 100/1.7
45. RO2-2M 75/2 VS LOMO Zh-53 75/2 VS LOMO RO506-1 80/2
46. Projection aplanates: "Petzvali" and "Richter"

The names of the lenses correspond to their exact spelling on the body.

Conclusions

The projection 35KP-1,8 / 100 turned out to be quite a 100 / 1.7. The lens demonstrates the limits of the classic 6/4 optical design. Adapted to a two-aperture version, it allows you to effectively juggle shooting parameters to fit any scene.

You will find more reviews from readers of Radozhiva here.