LOMO P-5 F=90 1:2. Overview of a projection lens adapted for mirrorless cameras by Rodion Eshmakov

Material on this lens especially for Radozhiva prepared Rodion Eshmakov.

Lens view after adaptation.

Lens view after adaptation. increase.

LOMO lenses of the P- series are relatively inexpensive film projection lenses for stationary 35 mm KPT film projectors. Three series of lenses are known:

P-4 - apparently the oldest. There are both coated and non-coated lenses with focal lengths from 90 to 150 mm (it is possible that there were longer options). They have a relative aperture of 1:2. Produced by LOMO and previous enterprises (GOMZ).

P-5 - coated lenses manufactured by LOMO with focal lengths from 90 to 180 mm with a relative aperture of 1:2.

P-6, P-6m - coated lenses manufactured by LOMO and its predecessors, with focal lengths from 90 to 140 mm (it is possible that there were longer options) with a relative aperture of 1: 1.6.

All listed lenses use the same lens optical design. Petzval, that is, they are aplanats (lenses with a curved image field), similar in characteristics to lenses KO (scheme "Kinolux"). P-series lenses can be considered more "advanced" in comparison with triplets for overhead projectors, but at the same time they are significantly inferior in optical quality to anastigmats of the type Ж, Ro and OKP and 35KP.

Specifications (Yakovlev A.F.: "Catalogue of lenses developed at GOI"):

Optical design - 4 lenses in 3 groups, "Petzval";

Schematic diagram of the P-5 90/2 lens.

Schematic diagram of the P-5 90/2 lens.

Focal length - 90 mm;
Relative aperture - 1: 2;
Field of view angle (frame 16×21 mm) – 19°;
Coated frame - 36×24 mm;
Rear focal length - 43 mm (not suitable for SLR cameras);
Frame diameter - 62.5 mm;
Weight - 0.7 kg;
Features - does not have an iris diaphragm and a focusing mechanism.

Lens construction and adaptation

LOMO P- lenses consist of two blocks with lenses screwed into a simple tube-shaped body. No frills. The front optical component is rolled into a frame, the rear one is partially disassembled with the last lens removed. The third lens is rolled into the frame. By the way, the front component of P- lenses can be used separately as a soft lens. The result of shooting with the front gluing lens P-5 90/2 (as it turned out) is shown here.

Optics P-5 90/2 has a very unstable antireflection coating of a bright purple color - wiping the lens of the objective can damage it. Through the lens, the lens turns yellow-green, like many other Soviet lenses with a similar finish.

Due to the fact that the light diameter of the front and rear lenses of the lens is 45 and 40.5 mm, and the outer diameter of the body is 62.5 mm, there is a lot of free space inside the lens to install a diaphragm with a sufficient light diameter (at least 43 mm). True, finding such a diaphragm is not very easy. The important thing is that this does not require a radical alteration of the body or the manufacture of a body from scratch, which is a traditional quest when adapting lenses. KO. The diaphragm control mechanism is made using the 3D printing method.

It is convenient to use factory-made M65-M65 macrohelicoids as a focusing mechanism. I used a 25-55 helicoid with a custom M65-M39 shank to connect to mirrorless cameras. Helicoids supplied from China have a very unfortunate lubricant: it needs to be replaced so that the lens can be used at low temperatures. It is also worth paying attention to the conical shape of the shank, which is due to the requirements of ergonomics: if the shank is made with a constant outer diameter, then there may simply not be enough room for fingers on the camera handle.

To work with 44×33 mm cameras, it is preferable to use P-5 100/2, and through an adapter shank with a larger hole diameter than the M39 thread.

It will not be possible to fully adapt to LOMO P-5 90/2 SLR cameras, and 100/2 can be put on Canon EF with certain tricks.
Photos of the adapted lens are shown below.

Optical properties

Compared to aplanat KO-90 90 / 1.9 projection LOMO P-5 90/2 has a much worse optical quality. At an open aperture, the lens has pronounced spherical and spherochromatic aberrations, and at a small distance from the center, strong coma and astigmatism are already observed. Aperture down to F / 2.8 reduces aberrations to a more or less acceptable level - the lens becomes quite sharp in the center and slightly better at the edge. At the same time, it is almost impossible to achieve excellent sharpness at the edges of the 36 × 24 mm frame due to astigmatism, even within the curved image field.

The contrast under normal lighting conditions in the image formed by P-5 90/2 is good. In backlight, the lens is highly prone to flare with color veiling and the appearance of various artifacts. This, as well as the spectral features of light transmission, distort the color reproduction of the lens. Backlit installation white balance and tones do not have a "correct" position and are rather a means to achieve a certain creative effect.

Like the fast aplanats KO, the P-5 90/2 lens has an expressive bokeh. But it differs greatly from Kinolux due to a completely different profile of residual aberrations. Thus, the lens tends to produce "bubbles" with colored edges (spherochromatic aberrations) on a blurred background, which "flatten" towards the edges of the image (geometric vignetting and astigmatism). Due to the curvature of the field, the area of ​​​​these background blur figures from the center to the edge almost does not decrease, and maybe even grows, which creates the very bright bokeh swirl effect, even more noticeable than that of Helios-40 and others anastigmata. The degree of background blur in the central composition of the LOMO P-5 90/2 is greater than that of other similar lenses precisely because of the curvature of the field. In general, LOMO P-5 90/2 is a very interesting and outstanding lens.

The following are sample photos taken with the Sony A7s full frame camera.

Other movie projection and movie shooting reviews:

  1. RO3-3M 2/50
  2. PO 500-1 F9 CM. 1: 2 P (review from the reader)
  3. 2/92
  4. F = 92 1: 2
  5. ОКП-6-70-1 F=70 1:1,8
  6. LOMO RO501-1 F = 100 1: 2 (+ materials from the reader)
  7. LOMO RO500-1 F = 90 1: 2
  8. 16KP-1,4 / 65 (review from the reader)
  9. 35KP-1,8 / 70
  10. 35KP-1,8 / 75 (review from the reader)
  11. 35KP-1,8 / 85
  12. 35KP-1.8 / 120 (review from the reader)
  13. 35KP-1.8 / 100 (review from the reader)
  14. LOMO P-5 F = 90 1: 2 (review from the reader)
  15. LOMO P-5 F = 100 1: 2 (review from the reader)
  16. ЛОМО ОКС1-40-1 40/2.5 (review from the reader)
  17. LOMO J-53 F = 75 1: 2 (review from the reader)
  18. LOMO J-54 F = 85 1: 2 (review from the reader)
  19. LOMO OKS1-300-1 F = 300 1: 3.5 (review from the reader)
  20. Tair-41 50/2 (review from the reader)
  21. KO-120 1: 2,1 120mm
  22. KO-90 1: 1,9 F = 9cm (review from the reader)
  23. KO-120M 1: 1.8 F = 120mm (review from the reader)
  24. KO-120M 120 / 1.8 with a diaphragm and helicoid (review from the reader)
  25. KO-120 1: 2.1 F = 12cm (review from the reader)
  26. LENKINAP RO500-1 F = 9cm 1: 2 P (review from the reader)
  27. Schneider Super Cinelux 70/2 (review from the reader)

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

Conclusions

Like other similar aplanat lenses, this Soviet petzval LOMO P-5 90/2 is primarily a “creative” portrait lens. Its optical flaws, which are completely unacceptable for "top" "professional" solutions, are desirable in tasks where you want to get a "fairy tale" and not a "reality".

You will find more reviews from readers of Radozhiva here... All Rodion reviews in one place here.

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Commentary on the topic: LOMO P-5 F=90 1:2. Overview of a projection lens adapted for mirrorless cameras by Rodion Eshmakov

  • Vlad

    Yes, the drawing is very similar to the G-40, so you can’t even tell it apart.
    Glass certainly deserves attention in artistic experiments.
    You can take it.
    Thanks for the review.

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