Nameless brass aplanat 150 mm F/8, second half of the XNUMXth century. Review from Rodion Eshmakov

Material on the lens especially for Radozhiva prepared Rodion Eshmakov.

Thank you for the lens provided for preparing the review Nadir Tulasheva.

Aplanats - simple four-lens lenses that provide good correction of all distortions except field curvature - were common "standard" lenses from the moment they were invented in 1866 until the advent of anastigmata - Paul Rudolf's Protar and Harold Taylor's Triplet. Unlike fast aperture (~F/3-F/4) Petzval "portrait" lenses, aplanats were usually quite "dark" (~F/8) to provide acceptable image quality across the field. Aplanats were made by many different companies, and there were different versions of lenses - both long-focus (~ 200 mm and more) for large-format cameras, and relatively short-focus (100-150 mm) for "compact" (close to film medium format cameras of the XNUMXth century). The simplest late short-focus lenses, which were supplied with inexpensive cameras at the beginning of the XNUMXth century, sometimes did not even have a diaphragm. In the XNUMXth century, lenses were equipped with Waterhouse plug-in diaphragms, and some later lenses even had an iris diaphragm.

This article features an unmarked aplanat lens from an unknown manufacturer. The presence of a hole for plug-in diaphragms and the design of the body suggest that this lens was made around 1870-1880, that is, today its age is almost a century and a half. Read also other review articles about using very old lenses on modern cameras:

• Petzval lens from the "magic lantern" 180 / 4.5 A. Darlot 1862
• Ross London Wide Angle Xpress 5in f/4 - 1930s aerial photography lens
• Carl Zeiss Jena Tessar 1:2,8 F=7,5cm - 1938 medium format lens

Specifications:

Optical design - 4 lenses in 2 groups, aplanat;

Focal length - 150 mm;
Relative hole - F / 8;
The angle of the field of view is approximately 60°;
Diaphragm - Waterhouse plug-in diaphragms;
Aperture limits - determined by the available set of plug-in diaphragms;
Fastening to the camera - inch thread, close to M39 × 1;
Features - does not have a focusing mechanism, optics without enlightenment, brass body.

The history of the creation of "Aplanat"

In the middle of the XNUMXth century, photography began to develop rapidly, growing requirements for the quality and characteristics of optics prompted researchers to develop a theoretical apparatus - Chevalier's intuitively created achromats used as standard and wide-angle lenses had poor field distortion correction, uncorrected distortion and low aperture. In 1840 Josef Petzval invented first lens, calculated with the help of a new physical and mathematical apparatus created by him. The Petzval lens had a narrow field of view and was not suitable as a universal lens, so the search for new solutions continued by other inventors.

In 1865, the German optician Hugo Steinchel created the first calculated mathematically symmetrical lens, called the "Periscope". This simple two-lens lens was symmetrical - this property corrected distortion and coma, but spherical aberration, astigmatism and chromatism remained uncorrected.

"Periscopes" were widely used because of their cheapness - they were "staff" of many budget cameras of the early XNUMXth century, they were used in overhead projectors and filmoscopes. There were also ultra-wide-angle versions of the "periscopes", such as the "Hypergon" by K. Hertz. A typical representative of the class of projection "periscopes" is a lens with a romantic name MP RSFSR GLAVUCHTEHPROM Plant No. 6 F = 7,7cm. By the way, today they are very relevant as soft lenses - the same Glavuchtekhprom 77 mm can be adapted for modern cameras as a healthy alternative "monocle» with interesting parameters 77/2. Unlike monocle (especially a lousy one like monocle from the lens of the long-suffering Helios-44) "periscopes" give a really high-quality soft effect without a catastrophic drop in sharpness at the edges of the frame.

After only 2 years, Hugo Steinchel, by replacing single lenses in the "periscope" with glued two-lens achromats, was able to correct spherical aberration, chromatism, coma, distortion and astigmatism (within a small field). Only the curvature of the field remained uncorrected, which was reflected in the name of the new lens - "Aplanat", that is, "non-flat".

It's funny that just a few weeks later, exactly the same lens was presented by the famous English optician John Dallmeyer. He created his "Rapid Rectilinear" (that is, "fast orthoscopic") independently of Steinchel.

Based on the optical design of Aplanat, many other lenses have been developed, including wide-angle and high-aperture projection. By replacing two-lens Chevalier achromats with three-lens Gauss lenses, Paul Rudolf received his famous six-lens Planar lens, the design of which, in various variations, was subsequently used in countless lenses from different manufacturers and different years of production.

150/8 aplanat construction. Use on modern cameras

Like many other old lenses of the 20th century, this aplanat has a brass body that has darkened with time. Only in the 30-30s of the XNUMXth century did brass begin to be chrome-plated to protect against corrosion, and from the end of the XNUMXs it began to be actively replaced by light aluminum.

There are no familiar controls on the lens, there is no marking, which makes it difficult to identify it. A slot on the body for plug-in diaphragms indicates that this aplanat was used as a filming one - projection optics were not equipped with diaphragms in those years, even such ones. Since the lens is designed for older gimbal cameras, it does not have its own focusing mechanism. The shutter in those years as a separate unit was not needed, because excerpts counted in tens of seconds.

The lens is very easy to disassemble for maintenance - the front and rear lens units can simply be unscrewed from the body. Usually, old symmetrical lenses allow shooting with one of the lens blocks, which leads to an increase in focal length with a decrease in aperture ratio and image quality.

It is worth noting the high quality of the blackening of the internal space of the lens, which many more modern lenses could envy.

Aplanat lenses are rolled into brass frames. Glasses do not carry enlightenment - anti-reflective coatings on the lenses of photographic lenses began to appear only in the early 40s.

Over the years, the lens glass has been eroded and looks somewhat cloudy - optical glass is rarely highly chemical resistant, it is not Pyrex. For some brands of optical glass, it is even possible to apply antireflection by chemical etching with aqueous solutions of acids or bases (historically the first method).

Adapting an old “dark” lens for use with modern cameras only involves selecting the right helicoid with the right mount to the camera, which is not difficult at all due to the huge (about 10 cm) back focal length of the aplanat. In the case of this lens, everything turned out to be very simple, since the thread of the lens mount to the camera turned out to be close to the M39X1, which made it possible to wind the M39-M42 ring and use the M42-M42 25-55 mm macrohelicoid as a focuser. I used as many as 2 such helicoids and another large Soviet macro ring M42-M42 to fit the working length.

Since the lens certainly has a collection value, the most important thing when adapting is not to affect the original design of the lens, not to irreversibly change its appearance.

When adapting, it is important that the space behind the lens has a good matte black: the lens covers a large frame and the “extra” light, scattering with multiple reflections from the focuser details, gives a pronounced veiling.

In terms of dimensions, the adapted lens is similar to the old manual 135 / 2.8 lenses, which once again reminds of the progress made in the development of optics over the years. Nevertheless, handling an aplanat is not at all burdensome - its parameters, dimensions and weight are not as extreme as those of ancient large-format dark and uninteresting anastigmata, which usually require very, very long "adapters", for which Nadira (the owner of this aplanat) aptly called them "mops".

Optical properties

Let's be honest - on small-format cameras at f / 8, even the notorious monocle out of the lens Helios-44. Indeed, 150/8 aplanat forms an image that is not bad in sharpness, somewhat softened by residual spherical aberration. Other distortions (chromatism, field aberrations, field curvature) are hardly noticeable on a small format frame. The image contrast is low, but much better than the one I had Ross London Wide Angle Xpress or maybe even better than a well-preserved Tessar 75 / 2.8. The lens has neither coating nor heavy lead flints in the optical scheme - its light transmission is almost neutral and the color reproduction is quite natural.

In my version of adaptation, the lens works confidently with a frame up to 44 × 33 mm, which also allows you to use it with shift adapter on full-frame mirrorless cameras. To achieve greater coverage, it is necessary to increase the light diameter of the mount to the camera.

From the point of view of artistic properties, the lens is quite interesting. To some extent, it can be considered as a "large-format 50/2.8" - the pupil size, which is associated with the value of the depth of field, is the same for a 150/8 lens as for a 50/2.8 lens. And this aplanat in the picture really reminded me of the Soviet 50 / 2.8 lens - “the best fifty dollars” Industar-26M - because it has a rather soft image and similar bokeh (discs with edging and a bright area in the center). It would be especially interesting to use the lens, of course, on medium format cameras.

Below are sample photos taken with the Sony A7s full frame camera. Some of the pictures were taken with Fotodiox EOS-NEX shift adapter.

Conclusions

Although this unnamed 150/8 aplanat is more of a collector's item, it must be said that there are absolutely no problems shooting with this lens today. And it's amazing. After all, even many modern zooms have a focal length of 135-150 mm aperture not much more - F / 5.6, and even at all F / 6.3. It would be very comical if this aplanat were not inferior to them in terms of sharpness - and this also makes us think about the progress made in the development of photo optics.

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