Lens 50 / 1.2 of the TVNE-4B tank night vision device (IPZ, Ukraine), adapted for mirrorless cameras. Review by Rodion Eshmakov

Material on this lens especially for Radozhiva prepared Rodion Eshmakov.

Type of adapted lens.

Type of adapted lens.

The protagonist of this article is another lens that was never intended to be used for photography. This unnamed super-aperture 50/1.2 lens was designed for use in binocular night vision devices with 1st generation image intensifier tubes, designed to operate in passive (that is, without IR illumination) mode: this is also indicated by the name of the device. TVNE-4 - Tank driver-gunner device for natural lighting, the fourth model of the device. They are equipped with Soviet and Ukrainian tanks and infantry fighting vehicles.

Appearance of TVNE-4B.

Appearance of TVNE-4B.

Letters Б or PA indicate the presence or absence of a built-in power supply in the instrument case. Each device has 2 lenses and 2 Image intensifier V-2 with eyepieces that create a stereoscopic image.

Device device TVNE-4B from the instruction manual. The numbers indicate: 1 - image intensifier tube V-2, 2 - middle body, 3 - shutter with a drive, 4 - body with an image intensifier tube, 5 - power supply, 6 - image intensifier cap, 7 - mirror prism, 8 - lens, 9 - mirror prism , 10 – eyepiece, 11 – image intensifier connector, 12 – image intensifier tube screen.

Device device TVNE-4B from the instruction manual. The numbers indicate: 1 - image intensifier tube V-2, 2 - middle body, 3 - shutter with a drive, 4 - body with an image intensifier tube, 5 - power supply, 6 - image intensifier cap, 7 - mirror prism, 8 - lens, 9 - mirror prism , 10 – eyepiece, 11 – image intensifier connector, 12 – image intensifier tube screen.

The manufacturer of this device, as well as TVNO-2B NVG, whose lens review was previously published, is the Izyum Instrument-Making Plant (Izyum, Ukraine). The same plant produced a number of film projection lenses in the USSR 16KP и 35KP.

Technical specifications

Optical design - 9 lenses in 4 groups, "Sonnar";

The proposed optical design of the TVNE-4B lens

The proposed optical design of the TVNE-4B lens

Focal length - 50 mm;
Relative hole - F / 1.2;
Estimated field of view angle - 36° (on image intensifier V-2/V-2K);
Covered format - 36×24 mm;
Rear focal line - ~ 4 mm;
Aperture - 15 petals, one of the petals with a protrusion that allows you to completely block the pupil of the lens;
Features - it does not have a focusing mechanism, due to the dimensions of the body and the size of the rear focal length, installation on most cameras is difficult or impossible at all.

Lens construction and adaptation

The lens is a lens block made in a heavy brass body. From the controls - a diaphragm ring with teeth for the drive gear (adjustment is carried out by turning the lever on the device body). The diaphragm itself has an interesting feature - one of its petals differs in shape by the presence of a protrusion that allows you to completely block the pupil of the lens. Disassembly of the lens block for maintenance is possible only from the nose, and the front lens protrudes strongly beyond the nose - you need to be very careful when handling the lens so as not to damage it. I had two lens blocks, below are photos of the lenses in their factory form.

I kept only one of them for experimentation, and the second one was purchased by an American enthusiast, who informed me about the successful installation of the lens on a Sony camera using an additional negative lens in front. But such an alteration is not our option, of course.

The main difficulty when installing the lens block on the camera is its very small back focal length, which is about 4 mm. This means that the back of the lens must be in close proximity to the camera's sensor, which is usually surrounded by the shutter mechanics, bayonet electronics, and light shaft. Fortunately, this distance is already enough to keep the possibility of using a mechanical shutter (which was unacceptable with a similar more short throw lens produced by LZOS). But the diameter of the back is still so large that the lens cannot be installed even on Sony full-frame cameras without modification.

Excess metal around the rear lens group was ground off so that the lens block in one position could move forward in the camera mount to achieve infinity focus. Thus, the strength of the body is preserved, but, moreover, a focusing mechanism with a strictly translational movement of the lens block is required. Another nuance is that the lens can be removed from the camera only when the rear group of lenses has left the sensor shaft (i.e., when focusing at ~1 m). Finally, the third feature - due to the presence of a rectangular matrix shaft, behind which the camera shutter is located, the working area of ​​\uXNUMXb\uXNUMXbthe rear lens is limited, which leads to pronounced irreparable geometric vignetting when focusing at infinity.

Another modification touched the diaphragm: the protrusion of the aperture blade was cut off to ensure the correct shape of the lens pupil. Below are photos of the lens block prepared for installation on the camera.

In the course of work, I accidentally damaged the rear lens, but, fortunately, this place is not actually involved in the formation of the image in a large range of distances in my version of adaptation (it is cut off by a frame around the matrix).

To install on a Sony A7s camera, it was necessary to grind the frame of the rear lens group in a special way.

To install on a Sony A7s camera, it was necessary to grind the frame of the rear lens group in a special way.

The Chinese macrohelicoid M42-M42 12-19 mm was chosen as the focusing mechanism. Options with M39 thread disappear due to a mismatch between the inner diameter of the mounting thread and the diameter of the back of the lens block. When connecting the helicoid to the camera through a thin M42-NEX ring, it was possible to achieve focusing at infinity.

Further, in order to protect the front lens from damage, a new nose piece was made with a protective edge, combined with a 49 mm thread for filters. After assembly, the lens looked like this:

It can be noted that the dimensions turned out to be comparable with the ultra-fast modern shooting analog 7artisans 50 / 1.1 - the creators of this lens were also inspired by the famous scheme L. Bertele.

The photographs also show that the lens slightly distorts color through the lens (even in comparison with some ordinary old photo optics): this, apparently, is the key feature of optics for passive night vision devices that use not only IR, but also the visible range. The light transmission profile confirms the observations: the spectrum appears to be perfectly flat up to the blue-violet region, where the light transmission is reduced. For this reason, a slight yellowness is still present. This time, the experimental conditions were simplified, so the light transmission coefficient of the system was not determined.

The light transmission profile of the TVNE-4B lens ranges from soft UV to near IR.

The light transmission profile of the TVNE-4B lens ranges from soft UV to near IR.

Of course, such an anti-reflective coating simplifies the use of a lens for photography, since you do not have to limit the choice of light sources, resort to complex color correction and other twists and turns that are necessary when working with a real lens. IR optics in the visible range.

Despite certain difficulties associated with the back focal length, this lens has been fully adapted for use with Sony full-frame cameras (compatibility on cameras of other systems needs to be clarified). The procedure is greatly facilitated by the presence of a factory iris diaphragm. It is also very good that it was possible to maintain the possibility of safe use of a mechanical shutter, which saves from pulsation artifacts world and beyond.

Optical properties

Unlike LZOS 37 / 1.0, this 50 / 1.2 lens is already capable of working with a full-frame matrix, having almost no problems with vignetting at close distances, but definitely requiring 4:3 cropping at infinity.

The level of aberrations, especially spherochromatic ones, was noticeably higher for the Izyum lens than for the Lytkar lens. Most likely, this is due to the fact that the 37 / 1.0 lens uses a more advanced nine-lens scheme - the addition of 3 more parameters contributes to better correction of spherical aberration, and along with it, longitudinal chromatism. At an open aperture, the lens forms a rather soft picture with pronounced chromatism in its most indecent form - blue-orange. With aperture up to F / 1.4, the situation improves noticeably, at F / 2 there are no problems with image quality in the central region of the frame. Field aberrations return to normal on a full frame only to F / 8-F / 11. In general, the image quality is close to 7artisans 50 / 1.1, however, it is noticeably sharper in the center and does not chromate so much.

Image contrast under normal lighting conditions is quite good and often does not even require correction. Color distortion is barely noticeable - automatic adjustment white balance in the chamber, as a rule, successfully copes.

The bokeh of the TVNE-4B lens is magical, there’s no other way to say it. It resembles bokeh 7artisans 50 / 1.1 and Jupiter 3, but due to the lower level of coma, sometimes it is noticeably softer and smoother - there is no “scale” effect. Due to chromatic aberrations, the disks have orange (out of focus) or blue (out of focus) fringing.

In general, the picture from the TVNE-4B lens is extremely interesting, but serious problems with chromatism and insufficient sharpness at an open aperture impose certain limitations. In my opinion, this optical scheme is very promising and, after some modifications, can be successfully used to create interesting portrait lenses.

The following are sample photos on the Sony A7s taken in full frame.

Conclusions

Already the third military "Sonnar" (previous two: 1, 2) got a peaceful life and once again demonstrated the value of a wonderful optical design, which is used by many fast lenses with an interesting pattern.

I was so impressed with the capabilities of these lenses that literally a week before the start of nightmare I talked with representatives of the Izyum Instrument-Making Plant, telling them about the prospects for using a number of their lenses known to me as photographic, for peaceful purposes. Perhaps someday we will be able to return to this dialogue, I believe in the best.

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Comments: 7, on the topic: Lens 50 / 1.2 of the TVNE-4B tank night vision device (IPZ, Ukraine), adapted for mirrorless cameras. Review by Rodion Eshmakov

  • B. R. P.

    Interesting work, the picture is good, thanks, Rodion.

  • German10

    Rodion, thanks for your work - wonderful work! I liked the picture.

  • Rodion

    Most likely, this lens in a simplified version without a diaphragm was also installed in the night vision devices (monoculars) PN-3A “Promin” manufactured by IPZ. But this is inaccurate - I did not find any documentation, the conclusion is purely from the geometric parameters of the lens and its appearance.
    PN-1 manufactured by IPZ use simpler optics, for the time being I’m clarifying.

  • VALERY

    Rodion. Thank you. I have already tested one of your lenses. Satisfied with the artistry. Here is the glass 50 mm F / 1.5, the lens of the tank night vision device TVNO-2B, adapted for mirrorless cameras

    • Rodion

      I would be very interested to see photos from the 77/2 periscope that I made for you. Unfortunately, I didn’t take a single normal shot of them, and I wouldn’t have done it in a month’s time. A semi-steb review of Glavuchtekhprom is already here, but no one has seen such a glavuchtechprom as yours)

      • GoodVALERY

        Good. Spring photos will be taken...

  • Rodion Eshmakov

    After removing and examining the rear lens of the lens (I did not touch it at all during the first disassembly), I found out that it is gluing. Thus, this lens is also nine-lens, like Lytkarinsky, but the rear component is more complicated.
    The geometry of the lenses in the last gluing is in question, the proposed version was given in the article.

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