The many-sided projection Triplet 78 / 2.8: methods of adaptation, comparison with analogs, application in "medium format". Article by Rodion Eshmakov.

Material on Triplet 78 / 2.8 specially for Radozhiva prepared Rodion Eshmakov (subscribe to Instagram!)

Two small cookies: Triplet 78 / 2.8 in a new type of performance and Industar-26m

Two small cookies: Triplet 78 / 2.8 in a new version and Industar-26m


Among projection lenses, Triplet 78 / 2.8 is like the Industar-50 among photographic lenses: it is the most widespread, affordable, cheap and simple lens that provides reasonable image quality. They used it not in cinemas, but for showing filmstrips. The lens was produced at different times in different factories in different buildings under different names (see. here).

There is no Triplet 78 / 2.8 in the GOI catalog of photographic and projection lenses, but the existing 80 / 2.8 is listed as a sighting lens for two-lens cameras. At the same time, no such serially produced camera was equipped with such a viewfinder. Probably, Triplet 80 / 2.8 Is the same lens as Triplet 78 / 2.8. You can check this fact by having both of these lenses and cross-changing the lenses with an image quality check after.

Lens card Triplet 80 / 2.8 in the GOI catalog and its technical characteristics.

Lens card Triplet 80 / 2.8 in the GOI catalog and its technical characteristics.

An experimental two-lens medium format camera “Optics”, But, apparently, this Triplet has found application only as an overhead projection.

Due to its prevalence and "convenient" parameters, Triplet 78 / 2.8 is a popular object of vivisection by amateur photographers who want to get a classic portrait lens at a modest cost. The large rear focal length and 6x6 cm frame coverage allow the lens to be adapted to almost any system - from mirror crop to medium format mirrorless cameras.

Because of the optical design, the Triplet 78 / 2.8 is often considered as a short analogue of the Meyer-Optik Trioplan 100 / 2.8, which, however, is not entirely correct (see below). In fact, as a photographic lens, the Triplet acts as an alternative to such more expensive short telephoto lenses and medium format cameras such as the Carl Zeiss Jena Tessar 80 / 2.8 (such, such, such), Biometar 80 / 2.8, MC Volna-3 80 / 2.8 and many others, including telezums.

Adaptation options for Triplet 78 / 2.8 lenses and some nuances

Triplet 78 / 2.8 lenses can be classified into 3 types according to the body design:

  1. Lenses for the Svityaz projector and the like are distinguished by a small-diameter lens unit, collapsible from the side of the lens nose. Such lenses can be adapted by installing instead of the front lens unit Helios-44M. An example of adaptation is given in one of my first articles on Radozhiv: here.
  2. Lenses in sleeves sharpened in a plastic body, disassembled from the side of the rear lens - have a larger body diameter in comparison with lenses from "Svityaz"; it is more difficult to install into the Helios body due to the rear location of the slotted nut of the lens unit. Adaptation example: here.
  3. Lenses of the LZOS DM-2 / DM-3 type have a front location of the slotted nut holding the lens; large in comparison with type 1 lens unit diameter and, moreover, an increased front part in comparison with type 2 (for DM lenses - with decorative design, for some "plastic" lenses not related to type 2 - without).

The lens presented in the review belongs to the "plastic" type 3: the lens unit in a dark metal case without decorative elements is structurally identical to the DM-3 lens manufactured by LZOS.

Before placing the lens unit in the focusing mechanism, it is important to pay attention to one fact: absolutely all Triplet 78 / 2.8 lenses suffer from the same drawback - neither lens chamfers nor inter-lens rings have matte blackening. High light scattering on the shiny inner surfaces of the lens unit is noticeable with the naked eye and without a test on the camera. If the need for chamfer blackening is controversial, then for lens spacers this is absolutely necessary. The ideal blackening material is carbon black, but it is very difficult to fix it on the surface of the part.

After blackening the ends of the lenses and the inner surfaces of the lens unit, nothing shiny is visible in the lens.

After blackening the ends of the lenses and the inner surfaces of the lens unit, nothing shiny is visible in the lens.

High-quality blackening allows a very (!) Significant improvement in the contrast of the formed image - this operation should not be neglected.

For alteration, you can use the Helios-44M body, but this option did not suit me because of the large mass of the helicoid, the large MDF and the ugly diaphragm. Therefore, I decided to adapt two such lenses (the second was just the usual LZOS DM-3) in a very "atypical" way: the lens units of Triplets were installed in the gutted lens units of expensive Jupiters-3 (naturally, these were substandard lens units with all sorts of irreparable defects), which have been slightly doped for a larger aperture opening. In this case, the thirteen-blade diaphragm of Jupiter-3 turned out to be in the lens position, which is quite acceptable for Triplets: it is close enough to the optical center of the system to work as an aperture, and not as vignetting.

In terms of diameter, the diaphragm from Jupiter-3 is suitable for Triplet 78 / 2.8 better than that of Helios-44.

In terms of diameter, the diaphragm from Jupiter-3 is suitable for Triplet 78 / 2.8 better than that of Helios-44.

Black 13 petals are much nicer than shiny 8 (Helios-44M or 44-2) or 6 (Helios-44M-x). The part of the body behind the diaphragm was also blackened - its contribution to the reduction of contrast was great.

Black 13 petals are much nicer than shiny 8 (Helios-44M or 44-2) or 6 (Helios-44M-x). The part of the body behind the diaphragm was also blackened - its contribution to the reduction of contrast was great.

It's funny to have a $ 3 lens unit in a $ 100 lens barrel, to say the least.

Front view of the adapted lens.

Front view of the adapted lens.

The resulting block was installed further into a Chinese macrohelicoid with an M42 thread, after which a threaded ring was added for filters and a diaphragm setting scale.

Aperture is controlled by rotating the nose of the lens. Polarizing filters are a little awkward to work with.

Aperture is controlled by rotating the nose of the lens. Polarizing filters are a little awkward to work with.

Macrohelicoid lives up to its name and provides MDF of the order of 0.35m.

Macrohelicoid lives up to its name and provides MDF of the order of 0.35m.

Naturally, the proposed alteration method is not even close to the simplest and, moreover, affordable. It is important to understand: the capabilities of the lens will greatly depend on the method of its adaptation, and it is difficult to find a truly high-quality version on the market - the costs of alteration usually want to be of the same order of magnitude as the cost of the lens unit, and the result is predictable: unsatisfactory image contrast due to poor or missing blackening of parts, underestimated aperture when using inappropriate apertures (see the adaptation of the DM-3 lens from the well-known Igor Skupnov - here... The aperture of Helios-44 is completely unsuitable for installation inside due to its small diameter), too "slow" focusing and too large MDF due to the use of a helicoid from "fifty dollars" and so on.

This option is distinguished by a very convenient focusing mechanism that allows you to climb the threshold of the macro range, a wonderful aperture and implemented measures to combat parasitic reflections. This adaptation easily realizes (and is realized) compatibility with the Nikon F mount.

Optical properties

By the brands of optical glass used (ordinary flints and heavy crowns), the 78 / 2.8 Triplet can be attributed to the optics of the technology level of the 30s, but, moreover, its lenses have a single-layer coating, therefore one should expect an optical quality intermediate between 80 Carl Zeiss Tessar 2.8 / 1938 и 1952.

I didn't have the opportunity to compare with the old Tessar 80 / 2.8, but paired photos with Tessar 80 / 2.8 (1952) clearly demonstrate the similarity of the overall contrast of the image of the lenses, the strong lag of the Triplet in sharpness and the difference in bokeh. Photos were taken with the aperture open, the second series was made using a shift adapter.

If we also recall the comparison of the Tessar 80 / 2.8 (1952) with Tessar 75 / 2.8 (1938), then we can assume that the Triplet has a better contrast in comparison with the Tessar 75 / 2.8 (the effect of optical enlightenment) and, possibly, visually better sharpness. Although, in my opinion, the Tessar 75 / 2.8 has a better reproduction of small details, while the Triplet seems to have a "high pass filter". In general, this is a collection of arguments about the subjectivity of the concept of "sharpness" and the importance of taking into account the differences in MTF of lenses.

One way or another, the sharpness at an open aperture in Triplet 78 / 2.8 is acceptable only for a half-length and close-up portrait, since the lens “eats up” small details due to pronounced spherical aberrations. On full frame and medium format, the influence of field aberrations (coma and astigmatism) at the edge of the frame is strong. With aperture down to f / 4-f / 5.6, aberrations in the center of the image field quickly disappear, at f / 5.6-f / 8 the lens does an excellent job in tasks where good sharpness is required - for example, in macro photography. The fact that "dark" triplets can in macro is not a secret: many inexpensive lenses for photographic enlargers were made according to this scheme. The field aberration situation improves enough by F / 8, but on a full frame, perfectly sharp corners can be obtained at F / 11. On a medium format, this is apparently an impossible task.

The contrast of the image is good, in the backlight the lens behaves quite tolerably. Color rendition - with a departure to the yellow-green area, nothing new (the effect of a typical single-layer enlightenment of violet shades), nothing to worry about. Of course, he cannot compete with modern fixes of this class with a multilayer coating of optics.

The lens works well with the shift adapter on a full-frame camera, since it is designed for a 6x6 cm frame.With the Fotodiox Shift EOS-NEX adapter on a camera with a 36x24 mm matrix, you can get frames with an aspect ratio of 4: 5 (36x45 mm) and 2,33: 1 (56x24 mm) by panning and subsequent stitching of images. When using the offset along the short side of the 36x24 mm matrix, the area of ​​the 36x45 mm frame turns out to be larger than that of medium format Fujifilm G cameras (frame 44x33 mm). On a mirrored medium format like Pentax 645 (60x45 mm frame) or Pentacon Six (60x60 mm frame), the lens may be difficult to adapt due to the lack of the length of the back focal segment. However, maybe someone will "shift" it on a medium format Fujifilm for $ 4k?

From an artistic point of view, the Triplet 78 / 2.8 should be considered as an excellent (I do have a few shots from these lenses that I still like) a soft-focus portrait lens at open aperture and a fairly tolerable short telephoto lens at F / 4 and beyond. Triplet 78 / 2.8 practically does not show "bubbling" bokeh in the full frame; On cameras with APS-C matrix, however, characteristic "bubbles" can be seen more often (this turns out to be in accordance with the observations of Arkady Shapoval described in this article). In general, for "bubbles" it is better to take it on the crop.

Below are sample photos on Triplet 78 / 2.8 and full-frame Sony A7s. Some of the photos were taken using a shift adapter (they do not have EXIF).

Conclusions

Triplet 78 / 2.8, although it seems simple, but with proper execution and skillful handling, it can give an excellent result at the level of the more expensive "eminent" optical vintage, for which they give completely different money. The lens is interesting both in crop and full frame, and now you can also try it in medium format ("cheating" or relatively "fair"). Lightness and compactness can also play a significant role in the fact that more and more good photos will be taken with this lens, and not with some heavy and large 85 / 1.4.

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

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Comments: 7, on the topic: Multi-faceted projection Triplet 78 / 2.8: ways of adaptation, comparison with analogs, application in "medium format". Article by Rodion Eshmakov.

  • Zheka

    👍

  • TSerg

    Thank you for your work in giving the old optics a second life!
    Rodion, how do you return it with soot? Share your experience if it's not your personal secret. I tried it and was not satisfied. It is scattered both on varnish and on paint (as bases). Moreover, the finer the soot, the faster it begins to crumble.
    I liked the Triplet drawing.

    • Rodion

      Sometimes it settles well on a water-based varnish, then fixes tolerably well. But, of course, there is no resistance to abrasion. But it does not crumble either. Sometimes you can just precipitate without a base - particles on the electrostatics of some kind are kept there at least.

      • Jea reth

        Rodion, have you ever used toner from laser printers? I somehow inked a frame window with it in shift-8m, it was a very good result. The main thing is not to breathe toner in the process)

        • Rodion

          I tried it, of course. But it is worse, much worse. It is not easier to apply - it is also hydrophobic.

      • TSerg

        Thank you for your answer, Rodion. I just used water-based varnish. Not really that. Two years ago, he blackened the inner surfaces of the projector from LETI (92/2) with soot. This year, this lineup began to fall off the metal. I had to disassemble again, peel off the varnish with soot and blacken with matte Revell paint for the models. She has a much better result. And then one modeler suggested to try on oil varnish, not to sprinkle, but directly stir the soot with it, and then paint. He says it dries for a long time. But the result that he showed me on the model is very good. I will look for an oil-based varnish and try. A good result is still obtained if you use the powder from the gas mask box. Only it needs to be crushed (on a coffee grinder, for example). And it seems to me from memory from a special course on civil defense that there is activated carbon. But shaped into tiny balls.

        • Rodion

          Thanks for the advice, I'll try. So far, I was lucky - it did not fall off.

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