A number of Era lens models were produced in the USSR for microfilm installations. Era lenses, including Era-6, are built according to the optical scheme of an asymmetric semi-glued anastigmat of 6 lenses in 5 groups. Depending on the width of the films on which the originals were reshomed (films of 16, 35, 70 mm), the focal length of the lenses varied from 105 mm (Era-7) to 150 mm (Era-13). The maximum aperture value is from 2.8 to 4.5. These lenses are characterized by high sharpness, contrast and near-zero vignetting.
To use this optical scheme in 35 mm DSLRs, the flange focal distance was lengthened at the base scheme. The high-aperture standard lens created at the Krasnogorsk plant was named "Era-6" 50 / 1.5 (the hole is almost 1.4! By the way, the real aperture of the Leutz Summilux-M 50 / 1.4 is also 1.5: according to the magazine "Popular Photography", p. 49, no. 8, 1994). It was produced as an interchangeable lens for cameras with a M 42 x 1 landing mount in two modifications: Era-6M and Era-6A (the latter also has a mount for a 42x1 camera, but the shank is easily removable for replacement with adapters: M 39x1, etc.
I learned about this lens in the late 80s, when, having acquired "Zenit-12hr“, I just started to consciously engage in photography. In one of the stores selling used photographic equipment, I met Vladimir Soshnikov (IMA-press publishing house). It was the first, though capped, acquaintance with a professional. After praising my desire to improve my skills and the acquired MC Zenitar 50 / 1.9, he said: “It would be better if you buy an Eru-6. Good lens! And leaving his business card, he left. After that, I repeatedly heard very flattering reviews about this “lens” and even saw a couple of black and white photographs taken by it (in polygraphic and natural form). The quality was very good.
I did not have imported equipment then, and it was still difficult to obtain. I wanted to buy a threaded high-aperture lens of excellent quality. I began to look for "Eru" in Moscow second-hands, at a flea market in Izmailovo, in other cities. Most of the sellers did not even know what Era was. Those in the know, shrugged their shoulders - we know what it is, but have never even seen it (or an option: “we had one such lens three years ago”). In general, this lens has become a legend: you can hear, but not touch.
Almost twenty years have passed (like Dumas). Once, having entered the editorial office of "Photocurier", I saw "Eru-6" on the shelf. In general, my complex feelings can be called surprise. I thought that I would never have to see this rare model of the domestic lens industry (Fig. 1). A legend revived! I think that readers will understand my desire to try out the lens in practical photography.
It turned out that I. Semikopov had already made a test shoot for them. He said: “The lens is very decent: sharp and satisfactory at drawing out of focus areas, its contrast is very moderate. Shadow detail is visible, but nothing special. " The control photographs 15 x 21 cm, leaving much to be desired in contrast, were taken indoors with the new version of Fuji 800. The film is good (better than the Kodak Extrapress 800), but with its own "gags". even with slight underexposure (and the real sensitivity is slightly lower than the nominal), the film gives a pastel color rendition and reduced contrast. I argued with the author of the controls about the reason for the low contrast in his pictures. As a result, I was asked to shoot on any film in order to be convinced of my own delusion.
So, I got into my hands a rather "well-deserved" copy with light abrasions on the body, a wedge mechanism of a jumping diaphragm, torn off screw slots (it was under repair), but with clean optics.
The first test shoot gave excellent color negatives and I decided to continue testing the possibilities. lens on a slide and on b / w.
The optical layout of the Era-6 is shown in Fig. 2.
It is a six-lens five-component asymmetrical semi-glued anastigmat, like its reproductive prototypes. The 3rd and 4th lenses located behind the diaphragm are glued into one component. Angle of the field of view 45 degrees. The optical characteristics indicated in the reference books are high. The external design of the lens is similar to the mass models Helios 44M-4,5,6,7. The large shiny metal aperture drive mode switch (manual / auto) to the right of the aperture scale gives it a similarity to the first Zenitar 50 / 1.7 model. Unlike Zenitars - "fifty kopecks", "Era-6M" does not have a constructive hood. The front edge of the frame protrudes above the edges of the front lens by about 5 mm. The front lens is strongly convex in comparison with Zenitar, Pankolar (manufactured by the GDR) and other staffs with a "hole" 1.7-2.0 However, the front lens of the "Era" does not go beyond the surface line of its mounting ring and is structurally well protected.
There are no inscriptions on the case about the presence of multilayer coating. The examined specimen of "Era" No. 800074, judging by its ability to generate glare and light scattering in difficult light conditions, is really not an MC. For the 80s of the twentieth century, the absence of a multilayer on optics of this class looks like nonsense.
Large diameter rear lens - 32.5 mm. Its surface is almost flat. Length lens (without covers) when aiming at infinity - 53.5 mm, when aiming at the minimum focusing distance, the length increases to 59.5 mm.
Largest diameter lens 65 mm. In the article by V. Feday "Lenses with the KMZ brand" (Photography magazine, Nos. 9-10, 1992) it is indicated that the largest diameter of the frame is 70 mm, and the length of the lens without caps is 66 mm. Perhaps several modifications were released, differing in the details of the design of the frame, the presence of a constructive hood, etc. (all batches of this lens were experimental). The minimum focusing distance indicated on the body is 0.5m. However, according to the information provided in the mentioned article by V. Feday, the nearest focusing limit is 45 cm. On our copy, the measured minimum focusing distance (to the film plane) is 49.2 cm. At the same time, the distance from the aiming plane to the front edge of the frame is 39.7 cm. In the same article, the mass of the lens is 370 g. The weight of our copy of the "Era" without covers is 365 g, with covers - 380 g.
Thread for filter 58 x 0.75 mm. The angle of rotation of the focusing ring from infinity to 0.5 m is about 150 degrees. This is not too much and not too little: it is convenient for precise focusing on close objects and not too wide an angle for quickly refocusing from near to infinity (no need to take your fingers off the focus ring). In general, it is done ergonomically. The distances of the focusing scale from 0.5 to 1 m are given in 10 cm. Further on, 1.2, 1.5, 2, 3, 5, 10 m and infinity are indicated on the lens barrel. The depth of field scale is given for aperture values of 16, 11, 8, 5.6, 4 (Fig. 1). There is a focus correction for shooting on infrared film.
6-blade diaphragm. Blackening of internal elements and aperture blades is somewhat better than that of Helios - 44M and MS Zenitar 50 / 1.9, but, as they say, leaves much to be desired ... The petals are still darker than the standard gray card and have a kind of graphite sheen.
They are lighter than other metallic internal parts visible through the lenses.
Before describing the optical properties lens I would like to devote a couple of paragraphs to the specifics of the national definition of photographic resolution (FRS). to test the FRS (hereinafter simply - the resolution) of lenses in the USSR, KN-1 and KN-2 films were used, intended for filming movies and containing spherical crystals of silver halides in the emulsion (when viewing 24 frames per second, the graininess of the image is not recorded by our visual system) ... The development of films with test shooting was carried out in the Standard No. 2 developer, which does not give fine grain on such photographic materials. Still - 5.75 g of Na2CO3 in menthol developer: D-23, just add soda and KBr (metol at pH = 7 works better and cleaner than in an alkaline medium).
Why so much baking soda to determine the photographic resolution? What kind of resolution is there, only light sensitivity. The developer Standard No. 5 was specially developed for KN and NK films, on which lenses are tested, (for 1.6 g of metol and 2 g of hydroquinone, only 2 g of borax and 0.5 g of KBr are needed to suppress the veil to create alkalinity and activate hydroquinone). Due to the adopted methodology, the resolution value indicated in the documentation was noticeably reduced (perhaps by 15 percent or more). Therefore, when comparing the resolution values of domestic lenses from reference books, with the resolution values of imported optics from foreign magazines, the score was “not in our favor”.
Flat crystals of silver halide, in contrast to spherical ones, aggregate less. As a result, the graininess of modern materials is less. The use of modern films with flat crystals for sensimetry of domestic optics (for example, Tmax-100, or FN-64, FN-100) will increase the resolution.
Domestic reference books indicate the resolution in the center of the frame (a circle with a radius of a little less than 4 mm), and after the slash, the smallest resolution “in the field”. As a rule, this is no longer a "field" at all. The field of the frame is the space between the circles with a radius of 4 and 18 mm. So, the resolution for the field is almost never given. Sometimes, the reference books indicate a more correct explanation for the value of the resolution after the slash - "margin of the field".
The edge of the field is understood as the part of the frame that is 19 mm diagonally away from its geometric center. Half of the diagonal of the 24 x 36 mm frame is 21.63 mm. And the world, located 19 mm from the center, is practically in the corner of the frame. This corresponds to the English term "cornes". In foreign sensitometry, there is no concept of "frame field", but there is a concept of the edge of the frame (edge), which is not an "angle". But more often the tests indicate the highest and lowest resolution for the frame: "center" / "corners" (center / corner).
In fact, as I understand it, both we and they measure in approximately the same areas of the frame. So, in this respect, the measurement results are almost representative. In the factory passport of domestic lenses, the second resolution value indicates the smallest permissible resolution outside the center and outside the extreme corner points - whether it is from the very edge (19 mm) or closer to the center - for example, at a distance of 10 mm diagonally from the center (this also happens) ...
Sharpness. According to the manufacturer's specifications, Era-6 has a photographic resolving power (FRS) with a fully open aperture (in pairs of lines, center / edge) not lower than 45/22 mm-1 (for Ai-S Nikkor 50 / 1.4 - 45 / 25 mm-1). This is a very good sharp indicator, given the existing specific methodology for its determination in our country.
R. Il'nsky and A. Sheklein, referring to the leading designer of photo optics D.S.Volosov, give a table in their article. It indicates that a satisfactory image quality is possessed by optics with a resolution of 30-45 lines / mm-1 in the center and 20 lines / mm-1 at the edge of the field, with a resolution of more than 50 lines / mm-1 in the center and more than 35 mm-1. along the edge of the frame, the image quality is assessed as "excellent" ("Photography", №№11-13, p. 38, 1993). According to the quoted table of DS Volosov, "Era-6" undoubtedly belongs to the category of lenses that provide very good image quality.
True, according to the encyclopedic reference book "Photography" (edited by: Boyarova P. I., Trachun A. I., Shekleina A. V .; p. 114, Minsk, 1992), "Era-6" has a resolution of 40/18 mm -1.
Close resolution from domestic high-aperture lenses, produced for retail trade, had two lens: MC Volna - 4N 50 / 1.4 (produced at the Arsenal plant - now produced under the brand name ARSAT 50 / 1.4) and extremely rare MC Volna-8N 50 / 1.2 (now not produced). The resolving force of the latter was determined according to TU as 40/25 mm-1.
The test still life included two dashed worlds cut from an old photography guide. One was located closer to the center, the other closer to the edge of the frame (Fig. 3). On Fuji Superia 100 film, the lens gave a resolution over the entire "field" of the frame at a full hole - the correct 35 line pairs per mm. The fine hairs of the polar fox cap are clearly visible, even at the very top edge of the frame, and other small details. The impression is that the resolution is more than 35 pairs, and the field of a target with a resolution of 40 pairs of lines / mm cannot be distinguished only because of the coarse grain (the grain, when the photograph is enlarged to 40 x 60 cm, reaches a size of almost 1 mm in diameter, which, apparently, associated with insufficient quality development, although performed in percentage at a price of more than 30 rubles).
For testing, I used a lightweight Velbon-2000 tripod, not a 100kg optical bench. In addition, I simply leaned the worlds against the spine of the book and their planes were not perpendicular to the optical axis of Era-6 1.5/50, but made an angle of about 80-85 degrees. That is, the real value of the resolution, carried out according to the standard method, would be even higher.
Practical shooting showed very good sharpness both when shooting at low apertures (f = 2.8) and at full aperture. Shooting in unfavorable light conditions (very cloudy weather, in a dark corner of the courtyard, from low black clouds it began to drizzle) on a color negative film 100 units. with a shutter speed of 1/60 and f = 2.8 gave beautifully detailed, sharp, contrasting images: when manually printing from negatives, photographs were printed with a size of 40 x 60 cm. x 50 cm. But the trick is that the lens, oddly enough, made it possible to reproduce an image that was far superior in quality to the visual perception of the objects being shot.
From the frame taken at aperture 2.8, with an increase of up to 15 x 22 cm, more details are discernible than in a photograph taken with the Pentacon Pancolar 50 / 1.8 at an aperture of 3.5. When you enlarge the frames taken with the aperture open to a size of 20 x 30 cm, the sharpness of objects in the focusing plane is high, and the image contrast is good.
But the quality of the image created by the lens is determined not only by its resolution.
Distortion. Distortion in lens barrel and very hefty for fifty dollars. When shooting from a distance of about 5 m, the distortion along the short side of the frame is about 1.1% (in the "angular" or "sine" value - 2.2%, see "PHOTO Courier", №№25-26, 2001, p. 1 11). The angle of distortion by which the direction of the straight line is deflected around the periphery of the frame is about 0 ° 17 '. The “barrel” along the long side of the frame is more noticeable and amounts to 2.8-2.9% (“angular magnitude” 5.6-5.8%). The deflection angle of the straight line is 1 ° 40 '. Such distortion already spoils architectural subjects. This lens is also of little use for reproduction photography.
For "Era-6» The amount of distortion when shooting from a minimum distance of 50 cm is 2.9% (in the "angular" value - 5.8%). The distortion is worse than some 28-70 zooms at the 28mm position. And this is critical when shooting, where the fidelity of the transfer of proportions and lines is important. But this feature limits the choice of scenes for shooting. For comparison: MS Zenitar 50 / 1.9 when aiming at 50 cm gives distortion not much less. But significant distortion is not yet a sentence. The distortion of Planars-"staff" is less. It is larger than that of the "staff" Minolta, Nikkor and Pentax (see the magazine "Popular Photography" vol. 98, No. 5, 1991 and vol. 98, No. 9, 1991). Large lens distortion does not mean that they are worse. Just reproductions from small originals, you need to shoot with macro lenses.
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