Monday, September 21, 2026

THE FIRST SUPER WIDE ANGLE LENS FOR LEICA - ZEISS HOLOGON


 
Zeiss Hologon 15mm f/8 on Leica M4-P


By Heinz Richter

Modern lens design techniques have presented us with a relatively large number of super wide angle lenses of 15, 13 and even shorter focal length.  All of them are very complicated, multi element designs in order to avoid visible distortion and lack of sharpness due to under corrected optical aberrations.  These lenses have become actually quite common, and few photographers even remember the super wide lens which started it all.

For many years, 21 and 20mm lenses were the maximum 35mm photography had to offer.  Anything with a wider angle of coverage had to be of a fish eye design with all the draw backs of pronounced barrel distortion.  All of this was changed with the introduction of the Zeiss Hologon 15mm f/8 in the early 1970s.  This was unusual in many respects.  Not only was the Hologon the first lens to achieve the unheard of angle of coverage of 110° without the usual fish eye effect, it was also the first post-war marriage between Leica cameras and Zeiss lenses.

 
Cross section of the three lens elements and the lens position inside the Zeiss Hologon camera body
Note the extreme proximity of the rear lens element to the film plane

The Hologon was initially developed for the Zeiss Hologon camera, which was part of the Zeiss Contarex system.  At the time it was thought impractical to offer the Hologon as an interchangeable lens, even with mirror lock up in the reflex Contarex.  Instead, Zeiss opted for a separate camera body, based on the Contarex with the mirror box removed and with the lens permanently installed.  It was their claim that extremely precise registration and centering was necessary for the lens to perform satisfactorily.

The Leica M cameras also met these criteria and the lens was made available in the Leica M mount also.  It was sold with a special 15mm viewfinder included.  The 15mm Hologon with its undistorted 110° diagonal angle of view is probably one of the most interesting lens designs ever.  Conventional lens design theories would indicate that a lens with such specifications would have to be of a multi-element design.  Computer aided research of wide angle lenses for aerial photography was conducted.  The normal concept of using many thin elements in wide angle lenses was actually revealed as unnecessary.  In fact, only three thick elements proved necessary to assure good performance of the lens.  Subsequently, the Hologon is of a triplet design, although bizarrely shaped.  Thus we have an example of an optical design which would not have been created by using conventional methods.  Furthermore, it is safe to say that manual computations for this design would have literally taken years to complete.

Construction of the lens made the installation of a diaphragm virtually impossible without compromising overall performance.  It was also impossible to offer a speed faster than f/8 for the same reasons, even though some of the modern optical glasses available today might offer the possibility to increase the speed of the Hologon.

It was felt that the restriction of a fixed aperture of f/8 would not pose any great disadvantage.  Besides, a graduated neutral density filter, offering perfectly even illumination across the entire image area, would effectively render a speed equivalent of f/16.  This could also be used in situations where the standard f/8 aperture would lead to overexposure.

Since the Hologon lens renders virtually distortion free images, the camera should be used perfectly level, to avoid excessively converging lines on verticals.  For that reason the 15mm viewfinder had a built-in spirit level, which helped the photographer keep the camera level, especially when shooting hand held.

The ability of an extremely wide angle lens to render virtually distortion free images allow the photographer to shoot many photographs where it is impossible to tell that an extremely wide angle lens was used.  But this is only one of the advantages of such a lens.  The other is that it produces photographs with a rather different perspective.  It is important to pay special attention to the foreground since the extreme angle of coverage will show a considerable amount of foreground when the camera is held level, even when used horizontally.  It is also important to hold a camera with such a lens very carefully.  It is quite easy for the lens to pick up ones knuckles.

The Hologon was designed to render optimum performance at f/8 across the entire image area.  Due to the optical glasses available at the time of its design, the lens did not quite show the high contrast level typically associated with the high quality optics from Zeiss.  In practical terms, this will result in perfectly sharp enlargement up to 8x10 inches.  Bigger enlargements might show a certain lack of crispness when inspected very closely.  Projection of transparencies, on the other hand, will show no adverse effects, because the projected images usually are not inspected very close up.  The same is true with big enlargements when viewed from a more “normal” viewing distance.

The Hologon allowed focusing from 8 inches to infinity.  Considering the great depth of field rendered by such a short focal length, one might initially think focusing to be superfluous.   But it was proven that the overall performance of the Hologon could be improved if the lens was focused properly.

 
Minneapolis IDS Center
15mm Hologon

Newer, more sophisticated lens designs have improved the speed of super wide angle lenses and even allow for reflex viewing.  Subsequently, the Hologon has long been discontinued.  But it deserves credit for having been the first of the super wides, and its unusual design will always give it a special place in the history of lenses for 35mm cameras.  Those who own a Hologon can consider themselves lucky indeed.

 
Minneapolis Lumber Exchange Building
15mm Hologon

 
50mm field of view
Please note: The 50mm field of view images in this article are not separately taken photographs, they were cropped form the original Hologon negatives to present the view of a 50mm lens in conjunction with a full frame camera

 
Minneapolis IDS Center Crystal Court
15mm Hologon

 
50mm field of view

 
Minneapolis Lumber Exchange Building
15mm Hologon

 
 50mm field of view



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Friday, September 18, 2026

ELCAN (Ernst Leitz CANada) HIGH RESOLUTION 35mm CAMERA SYSTEM FOR THE US NAVY


By Heinz Richter


In 1952 the Ernst Leitz company (the former name of Leica Camera)  established an overseas factory in Midland, Ontario, Canada.  The company was called Ernst Leitz Canada and produced a variery of items under the ELCAN (Ernst Leitz Canada) label.  Leitz had always manufactured specialty items for the military and ELCAN was no exception.  In the 1960s they were asked by the US Navy to develop a high resolution 35mm camera system.  This was based on the Leicaflex SL.

Leicaflex SL with 75mm f/2 ELCAN Lens
Photo: James L. Lager (ed.), Leica Illustrated History, Vol. II, 1994, p. 307, 309 and Vol. III, 1998, p. 319

Resolution, the ability of a lens to project fine detail has always been a measure of great importance in the evaluation of photographic lenses.  The following are excerpts from an article by Joseph A. Schantz, Assistant Head of Research and Development Department at the Navel Photographic Center in Washington, DC.

Research by optical glass manufacturers has resulted in optical glasses having improved properties with respect to secondary color aberration.  Since this glass became available lenses having complete color correction over an extended spectral range have been developed for a Navy 35mm camera system.

Since 1963 the Navel Photographic Center and the Navel Air Systems Command as a matter of continuous policy have expanded efforts to upgrade 35mmphotography on a systematic basis.  The aim of this work was not only to improve the quality of documentary and reported photography but also to improve intelligence collection capabilities of the Navy’s cameras.

While most of this type of photography by the Navy is classified, one application, according to a former Navy officer, was in the Mediterranean.  For instance, US Navy ships often came into close contact with Russian Navy vessels.  It was common practice to shoot a series of photographs of these ships during such encounters.  The relative ease of operation of a 35mm camera, compared to medium format and even more so large format cameras, proved to render better photographs with 35mm equipment.  It should be noted that the article by Mr. Schantz was written prior to the advent of digital photography.  However, the principles of lens design are essentially the same in digital photography also.  To get the necessary detail compared to medium and large format photography it was necessary to develop a special, high resolution 35mm camera system.  Mr. Schantz further writes:

It was recognized that the resolution of a lens is limited in part due to a lack of correction of secondary colors.  Based on the light refracting properties of available optical glasses, most lenses can only bring two wavelengths to a common focus.  The optical designer must choose these wavelengths to best suit the intended use of the lens.  All other wavelengths are then focused in planes predetermined by the properties of the glasses over which the designer has no control.

Until the advent of extra low dispersion glasses the only exceptions were apochromatic microscope lenses and some telephoto lenses for 35mm camera systems which incorporated lens elements made of calcium fluoride crystals or alum and some process lenses that used large opposite powers in their element configuration.  But these were limited to apertures of f/9 or smaller.

Lenses utilizing elements made of calcium fluoride have proven to be of very good performance.  But they are not without drawbacks.  Calcium fluoride unfortunately is very soft and scratches easily.  Therefore front elements made of calcium fluoride usually are protected by a clear front glass plate or a thin lens element made of conventional optical glass.  Furthermore calcium fluoride has a rather high temperature coefficient which means that it expands and contracts very much during temperature changes.  In some instances this had led to calcium fluoride lens elements literally shattering when objected to great temperature differences.  It is also the case that these elements do change their optical properties during temperature changes which makes it necessary to allow lenses incorporating such elements to be focused past the infinity mark.  With other words, while the performance of such lenses is quite high, this must be paid for with a number of drawbacks.

However, research has produced optical glasses that do display the same or similar properties as calcium fluoride, but without the above mentioned drawbacks.  The first such glass was developed in the late 60s and early 70s by the glass research laboratory at Ernst Leitz Wetzlar, the maker of Leica cameras.  Not until approximately ten years later were similar glasses made available by other glass manufacturers like Schott and Nikon.  These glasses are commonly referred to as extra low dispersion or fluor crown glasses.  They allow the easier design and manufacture of apochromatic lenses.  Only true apochromats have the ability to focus all colors of the visible spectrum at one common point.  Mr. Schantz further states:

A series of such apochromates has been designed and manufactured under contract by Ernst Leitz Canada Ltd (Elcan).  The lenses were designed by Professor Dr. Walter Mandler.  The lenses consist of: Elcan-R 75mm f/2, Elcan-R 180mm f/3.4, Elcan-R 450mm f/5.6.

File:R-75f2.jpg
ELCAN 75mm f/2
Photo: L Camera Forum

 
180mm f/3.4 Apo Telyt

 
Schematic of the 180mm f/3.4

Elcan-R 450mm f/5.6

These lenses were designed for the Leica R cameras and are color corrected from 400 to 900 nanometers.  These lenses permit photography in black and white, color and infrared with the same focal setting.  When subjected to a series of filtered responses,(measurements with colored light) of blue, yellow, red and infrared, the yellow, red and infrared responses were grouped over a focal plane spread of only 0.02mm.  (These are data for the 180mm f/3.4 which was tested at maximum aperture.  Initially a classified piece of equipment, the lens later became available on the civilian market as the 180mm f/3.4 Apo Telyt-R) The curve of the blue filter is shifted 0.07mm closer to the lens.  The maximum focal plane shift from blue to infrared is 0.09mm or ±0.045mm.  If this lens is used only for daylight operations (no infrared), the maximum focal plane shift is reduced to 0.08mm or ±0.04mm which is less than 1/2000 of an inch.  Considering the accuracies to which photographic cameras (from Leica) are built, this tolerance falls within those specifications.

Most camera manufacturers apply less stringent tolerances.  The industry average standard is 1/1000 of an inch, with a few manufacturers like Canon, Nikon and Contax going to 1/1250 or 1/1500 of an inch.  Leica cameras on the other hand continue to be made to tolerances of 1/2500 of an inch or more precisely 1/100 of a millimeter.  Tolerances applied for the manufacture of lenses often needs to be much smaller.  Starting with the optical glass, Leica applies a standard of ±0.0002% for the accuracy of the refractive index.  This compares to the international standard of ±0.001%.  The accuracy of the Abbe number, the measure for dispersion is ±0.2% for Leica compared to ±0.8% internationally.  For the manufacture of individual lens elements Leica allows production tolerance of no more than ¼ lambda or ¼ of the average wavelength of light which corresponds to approximately 500 nanometers or 0.0005mm for the accuracy of the lens surface.  In comparison, the tolerances applied by other lens manufacturers are ½ lambda or 0.001mm.  For the production of aspherical lens elements Leica applies even tighter tolerances which cannot exceed 0.03 micrometer or 0.00003mm.

For comparison purposes the same procedure was repeated with a representative sample of a high quality photographic achromatic objective (only corrected for the primary spectrum).  The Leica Elmarit-R 180mm f/2.8 lens was stopped down to f/3.4 for the test.  It is strikingly evident that the different colors focus at quite different locations on the lens axis.  The maximum focal plane shift from blue to infrared is 0.5mm compared to 0.09mm for the 180mm f/3.4 lens.  This amounts to an increase by a factor of 5.6.  The maximum focal plane shift under daylight conditions is 0.2mm as compared to 0.08mm for the 180mm f/3.4 lens.  This amounts to a factor of 2.5 over the 180mm f/3.4 lens.

The most obvious advantage of the 180mm and the 450mm lenses occur when high resolution films are used.  The 180mm lens would outperform any other lens with any type of photographic emulsion (or digital sensor)

The performance of the 180mm Apo Telyt-R is well known and Mr. Schantz’s article only confirms the fact that the 180mm f.3.4 Apo Telyt-R is one of the best lenses ever made.

Mr. Schantz writes the following about films:

When the improved lenses were tested with regular fine grain films, little improvement could be noticed over the performance of regular good lenses.

Through the cooperation of film manufacturers a number of film samples were tested for performance with the new lenses.  Two classes of film emulsions gave promising results.  These classes were (a) high definition aerial films and (b) high resolution document copy films.

These aerial films are fine grained, slow, high contrast and have extended red sensitivity.  However, when processed as normally recommended by the manufacturer for aerial use, they have too high contrast for general ground photography.  The same holds true for the high contrast copy films since they were designed for high contrast microfilming.

Kodak High Contrast Copy Film when processed in the POTA developer of Marilyn Levy (Levy, M., “Wide Latitude Photography,” Science and Eng. Vol. II Number I, January, February 1967) yield excellent high resolution negatives with adequate film speed.  The Agfa High Contrast Copy film gives a practical combination of good resolution and emulsion speed.

According to the research done by Mr. Schantz, the best resolution obtainable with conventional film is 250 – 300 l/mm compared to 550 l/mm with the Agfa High Contrast Copy Film and 600 l/mm with Kodak 5069 and 3414 film.

Those are very impressive figures.  It was soon determined that in order to make enlargements that would show this amount of detail, a special enlarger was necessary.  For that reason Leitz made a modified version of their Focomat II enlarger where the standard light source was replaced with a point light source.  Only such illumination systems are capable to reproducing extremely small detail from a negative.

The 35mm high resolution camera system was classified material for several years.

Of the three lenses, the 180mm f.3.4 ELCAN lens proved to be the most practical one which resulted in a declassification, allowing Leitz to make the 180mm part of their lens line for the Leica reflex cameras.  It entered the market in 1975 as the 180mm f/3.4 Apo Telyt R.  Even today it ranks as one of the best lenses ever made for general photography.


For other articles on this blog please click on Blog Archive in the column to the right

To comment or to read comments please scroll past the ads below.

All ads present items of interest to Leica owners.

_______________________________________________________________________

EDDYCAM - the first and only ergonomic elk-skin camera strap     
 www.eddycam.com        

      



Buy vintage Leica cameras from 
America's premier Leica specialist 
www.tamarkin.com

 http://www.tamarkin.com/leicagallery/upcoming-show


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