Ross London Wide Angle Xpress 5in F/4. Review of the aerial photography lens of the Second World War by Rodion Eshmakov

Material on this lens especially for Radozhiva prepared Rodion Eshmakov.

Front view of the lens.

Front view of the lens. increase.

For the lens provided for review, I thank Nadira Tulasheva (Instagram).

Aerial photography, which arose with the invention of aircraft, has always placed the highest demands on the lenses used. In the pre-digital era, aerial photography was carried out on wide film (medium format and larger) and large format photographic plates. In this case, the orthoscopicity of the image formed by the lens was important, high resolution, a wide angle of the field of view and a large aperture. It is difficult to create lenses with such qualities even today, and in the first half of the XNUMXth century, something from this list had to be completely abandoned. But the Second World War spurred the development of optics. For example, in different countries for the first time lenses with precise aspherical lenses, new super-heavy types of glass (including thorium) were obtained. For the needs of aerial photography, ultra-wide-angle lenses have been developed MM. Rusinova - the progenitors of modern wide-angle systems, as well as fast lenses D.S. Volosov "Uran».

This article features the Ross London 5in (127mm) F/4 British military wide-angle aerial lens, used by Royal Air Force (RAF) torpedo bombers with a motorized panoramic camera for documenting attacks - from dropping a torpedo to hitting.


Optical design - 6 lenses in 4 groups, "Plasmat";

Schematic diagram of the "Plasmat".
Focal length - 127 mm (5");
Relative aperture - 1: 4;
Aperture - 16 blades;
Covered format - 5×7” (13×18 cm);
Estimated format - 6 × 18 cm (panoramic image);
Field of view angle (diagonally on 13×18 cm format) – 82°;
Features - does not have a focusing mechanism and attachment to modern cameras.

Historical background

The symmetric anastigmat "Plasmat" was developed in 1918 by the famous German optical physicist Paul Rudolf, the creator of the first anastigmat lens "Protar" (1890), as well as such well-known lenses as "Planar" (1895) and "Tessar(1902).

Portrait of Paul Rudolf.

Portrait of Paul Rudolf.

The predecessor of the Plasmat is the equally famous Dagor (an anagram for Doppel Anastigmat GOeRz) F/6.8–F/8 by Karl Paul Hertz: a symmetrical six-lens anastigmat consisting of two glued triplets. This lens featured good aberration correction and high image contrast due to the small number of glass-air boundaries, which was very important in an era when optical coating technology did not exist.

Schematic diagram of the lens "Dagor".

Schematic diagram of the lens "Dagor".

Paul Rudolf enlarged aperture of the Hertz lens by approximately 2 times, introducing additional correction parameters by separating internal menisci from triplets. It is not entirely clear why the resulting lens became more widespread at the beginning of the XNUMXth century than the Planar, which has the same number of lenses and components - perhaps the initial calculation was more successful for the Plasmat. One way or another, up to the invention of Willy Merte semi-symmetrical aperture "Biotara”, the creation of Paul Rudolf was very popular and developed successfully. "Plasmat" firmly entrenched in the camp of format optics, reproduction lenses - symmetry made it possible to completely get rid of distortion, and the six-lens scheme allows a high degree of aberration correction. The Plasmat scheme is used by no means ancient photographic enlargement lenses Rodenstock Rodagon, Schneider Componon-S.

In 1922, Paul Rudolf designed a small-format fast aperture (up to F / 1.5) Kino-Plasmat for the needs of film production.

The principle scheme of Kino-Plasmat is distinguished by the location of internal menisci and the rejection of complete symmetry.

The principle scheme of Kino-Plasmat is distinguished by the location of internal menisci and the rejection of complete symmetry.

This lens was supplanted in the 30s - 40s of the XX century by Merte's "Biotars" and "Sonnarami» Bertele. The life of the "Macro-Plasmat", developed in 1926, turned out to be longer - its scheme turned out to be so successful that it is used even in modern lenses. For example, Canon EF 40 / 2.8 STM - This is an aspherical descendant of the "Macro-Plasmat".

Schematic diagram of "Macro-Plasmat".

Schematic diagram of "Macro-Plasmat".

Although the Plasmat was hardly intended as a wide-angle lens, there were variants from different manufacturers with a field of view of more than 45 °. For example, "Biogon" 35 / 2.8 Ludwig Bertele  competed with the previously developed semi-symmetrical "Orthometar" 35 / 4.5.

Schematic diagram of "Orthometar" 35/4.5.

Schematic diagram of "Orthometar" 35/4.5.

The old English firm of Andrew Ross, who had actively collaborated with Carl Zeiss before the First World War, used this scheme between the wars to develop aerial photography optics, including the Ross London Xpress 5in F / 4, achieving not only a significant expansion of the field of view, but and doubling the aperture ratio (typical format "Plasmats" had a relative aperture of ~ 1: 5.6). Today, these lenses are prized by both collectors and photographers using format cameras.

Lens construction and adaptation

The lens body is made of brass - quite heavy. The design is very simple: the front and back glues are separated by twisting the front and back of the case. Next, you can remove the meniscus and gain access to the diaphragm.

The copy that fell into my hands was very tired: I carried out its revision several years ago, it was very dusty and dirty. Unfortunately, the lenses have been eroded, and the adhesive has probably "aged" over the past 100 years, making the lenses appear somewhat "cloudy". They also failed to protect the front lens from damage.

At the request of the owner, I redesigned the lens for use with a small-format SLR camera, for which I built it into the helicoid of a substandard Komura 135 / 2.8 telephoto camera, which was then also given to me by one of Radozhiva's readers, Ivan Vasiliev from Tomsk. Photos of the adapted lens are shown below.

This adaptation option is not optimal, since the working field of the lens is severely cut by the focusing mechanism. A more correct option is to convert to a medium format like Pentax 67 or Pentacon Six. Nevertheless, the main goal was achieved - the lens saw the light.

Optical properties

If we evaluate the lens dryly, then by today's standards on a small-format camera it is very, very weak optically: at an open aperture it has pronounced spherical aberrations (“soft effect”), strong longitudinal chromatism (fringing) is manifested in some scenes. Good sharpness starts around f/5.6. The image contrast is very weak, this is largely due to damage to the optics, but the main reason is the lack of an anti-reflective coating on the lenses.

On the other hand, the Wide Angle Xpress 127/4 is not much worse in sharpness than the similar Soviet one. OF-457 137/3.5. In some ways, it is even better than the post-war Soviet "Tessar" Industar-24M 105 / 3.5. Given the covered format, the quality of the British lens is very good. Probably, in the absence of damage to the lenses, the Wide Angle Xpress 127/4 would have performed much better.

The old "plasmat" has a rather interesting pattern. Undercorrected spherical aberration, in addition to an interesting soft effect (and sometimes useful in artistic portraiture), leads to the appearance of characteristic “bubbles” in the bokeh - discs with a bright thin edging. As a result, the blurring of the background by the lens is quite outstanding.

As it turned out, even in this adaptation option, the lens is able to work with a shift adapter on a full-frame camera, allowing you to take pictures with crop factor ~0.7, which is comparable to 44×33 mm sensors of Fujifilm GFX medium format cameras. I believe that on large frame formats the lens would be even more interesting.

Below are sample photos taken with the Sony A7s full frame camera. Part of the photo was taken using the Fotodiox Shift EOS-NEX shift adapter. All photos required heavy contrast enhancement in Lightroom when processing RAW files.


I cannot say that I am very enthusiastic about the idea of ​​​​using old format optics on small format cameras - such lenses rarely have at least some attractive and convenient parameters. But this ancient Plasmat in 2018 still managed to surprise and hook so much that I decided to take it again specifically in order to test it on a full-frame camera with a shift adapter. The result I got gave me a positive impression of the lens. Who knows, maybe "Plasmat" will still be reincarnated in modern times as a fashionable high-aperture soft-portrait with this characteristic vintage pattern?

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

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Comments: 3, on the topic: Ross London Wide Angle Xpress 5in F/4. Review of the aerial photography lens of the Second World War by Rodion Eshmakov

  • Alexander Rifeev

    Eh, what good and even chic fashion models :-)))) So I remember: - Oh, what a woman, what a woman! I would like this ... :-))))

  • Tiger Bee

    Wonderfully draws, humanely, softly. And the bubbles are great.
    You know, even people who are very far from the frills of photography feel the charm of old photography, unconsciously these signs of old film life are perceived by everyone.
    And to shoot such antiquity is akin to ritual actions.
    Thanks for the review. I shoot with sonnars on a Nikon camera through an adapter. one of them was obviously altered from some device, I always thought from an airplane, but it is at 300. Then it was probably for geodesy. Nobody wanted to fix it for me. Therefore, I simply took the diaphragm out of it, it became lighter! by feeling from 4 to 2. And quite, well, I'm not a pro. I just like it.

  • Nicholas

    architecture is bombarded

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