Aerial Camera designed by Albrecht Brugger

• an image field in the range of large-format photography
• a relatively high maximum aperture permitting exposure times of 1/1000s and less with film speeds of about 100 ISO
• high imaging performance even at the full aperture
• high resolving power for fine details, limited only by the performance of the film used
• uniform high performance across the entire image field, not only in the center.

Brugger first fitted his cameras with serially produced Zeiss lenses for large-size photography in the 9 x 12 cm format. These lenses were - and still are - very popular among aerial photographers, as they offer very good imaging performance even with f-numbers around 8, whereas common large-format lenses have been optimized for working apertures of 22 to 32.

Brugger mainly used a 75mm Biogon® f/4.5 lens and a 135mm Planar® f/3.5 lens, both with a central shutter. After testing the prototype of a 150 mm Planar® f/2.8 lens, a heavy lens of the central shutter type, he orderd a lightweight 150 mm Planar® f/4 lens where no central shutter had to be taken into account in the beam path, which only had to cover a relatively small image format of 7 x 10 cm, and which did not need to provide any reserves in the image field for setting possibilities. In addition, it was designed for subject distances in the infinity range. At full aperture, it was supposed to offer a similar performance as the 150 mm Planar® f/2.8 lens at an f-number of 8. Brugger received three lenses of this type in 1972 and used them as his preferred optics for many years.

Brugger's working conditions changed over the years, involving increasingly high altitudes for photography. Due to the good experiences gained with his 150 mm Planar® f/4 lens, he ordered a lens with comparable imaging performance, but with a larger focal length. Carl Zeiss developed the 300mm Planar® f/4 lens for the relatively small 7 x 10 cm format, designed for subjects at infinity and without any reserves for setting possibilities. Within the scope of these specifications, the correction was pushed to a remarkably high level. The cromatic longitudinal aberration was corrected by the use of special types of glass. With a Petzval radius of 20 f, field flattening attained a markedly higher level than in normal camera lenses (approx. 5 to 10 f). An outstanding value was also achieved for spectral transmission which totals approx. 0.95.

In the mechanical design of the 300 mm Planar® f/4 lens, all measures were taken from the outset to ensure extremely effective absorption of straylight and thus to achieve maximum image contrast. Recent comparisons with current camera lenses have shown that Brugger's 300 mm Planar® f/4 lens of 1982 still sets an extremly high standard for excellent straylight absorption.

Two lenses of this type were manufactured for Albrecht Brugger. They finally made his dream of 1951 come true, permitting him both to take photos with his hand-held aerial camera which displayed the same fascinating reproduction of details as photos made with aerial survey cameras and to produce sharply defined pictures with a width of up to 10 meters.

Why did Brugger build his own camera?

I built this camera according to the motto "as small as possible and as big as necessary". The goal I had in mind for image quality was that provided by aerial survey cameras. The dimensions and weight of these instruments, however, make them unsuitable for hand-held use. The only way to come closer to achieving my goal was to build a small camera of superior precision which was versatile in use and easy to handle.

In view of the rare occasions when weather conditions permit high-quality aerial photography, I had to ensure that there was no shortage of film supply if the weather was good for several days on end - a risk I always try to minimize by following the principle "think before shooting" which explains my relatively economical film consumption. This aspect was the reason why flat film was not an option to be considered, especially since it is only "flat" by name anyway. Optimum flatness of the film, however, is of decisive importance for perfect aerial photography, as the photographed object represents a fine-meshed test grid which is uniform across the entire image area (I am assuming here that we are not talking about the mass production of common-or-garden aerial photos). We only have to think of the wealth of detail contained in a normal-angle photo taken from an altitude of a few thousand meters! Roll film with its paper base, on the other hand, has never been able to offer the flatness required - this is a lesson I had to learn before with the Hasselblad camera.

Central shutters did not provide the short exposure times required, and they also compelled the lens designer to force the bundle of rays through a small pinhole, which inevitably involves compromises in optical quality.

With these considerations in mind, I designed and built a camera for unperforated 70mm film which is pneumatically flattened by suction against the pressure plate during exposure. The net film format is 68.5 x 100mm. The pressure plate is lifted for film advance.

A focal-plane shutter permits a realistic minimum exposure time of 1/1500sec, or even less if certain concessions are made. The film magazine, lens, viewfinder and handle of the camera are exchangeable. The lens bayonet has a clear aperture of 88mm, approx. 95mm in front of the image plane. All film advance processes are electrically powered (12 V); the same applies to the generation and control of the vacuum for film flattening. Only the shutter is tensioned manually, which also controls everything else. The film magazine accommodates 45m of film and up to 60m of certain types of special-purpose film with a thin film base. A smaller magazine for about 5m of film with manual operation of the film advance is also provided. This magazine also uses vacuum for film flattening, the vacuum being generated outside the camera and fed via an "umbilical cord" - again at 12 V. Due to the exceptionally good film flattening these magazines may also be used in common photography.

The viewfinder is a large-format frame finder with 3-point sighting, the only type permitting the exact assessment of detailed photographic objects and full utilization of the photo format, and allowing you to keep an eye on the surroundings (horizon, observation of the airspace). Since I consider the 7x10cm format to be the "miniature format in aerial photography", its full utilization was of paramount importance for me. I have never been one for subsequent correction of the image section after exposure, since this inevitably impairs the achievable image quality. The shots should directly "hit the mark" while utilizing the full format. The individual components of the viewfinder are spring-mounted and tiltable, allowing them to give way under shock.

Needless to say, I did not build all camera components myself, but had some of them made by specialized manufacturers including Carl Zeiss. For some components, I was able to use off-the-shelf products (e.g. Linhof handle) and modify them, if necessary.

The fact that I designed this camera for my own exclusive use permitted me to "slim down" many components to just acceptable limits in a way that, for reasons of stability, would not have been feasible in a "foolproof" version intended for the general market. The result was an extremely favorable weight/performance ratio. However, this necessitates a great deal of skill and sensitivity in the use and operation of the instrument. The goal of easy handling has been achieved - this is convincingly borne out by the fact that I have flown the camera single-handed for decades with great success, i.e. I was the pilot and photographer at the same time. The camera was operated with both hands during these flights which not infrequently took me to altitudes of up to 6000m at temperatures of less than -20° C.

Large-format focal-plane shutters are difficult to obtain on the market because they are prone to problems. Linhof tried its hand at them decades ago and abandoned the attempt. The shutter contains various textile parts which are subject to wear, and therefore needs an occasional checkup. A counter indicates the number of shutter operations and is also used as frame counter. The focal-plane shutter is inserted in the side of the camera housing and can be removed for checking and for any maintenance work required.

The use of a focal-plane shutter (which, as previously mentioned, does not require any narrowing of the optical ray bundle) made it possible for CARL ZEISS to compute and design customized lenses exclusively for this camera. Needless to say, this was a special honor and can only be explained by the enthusiasm with which the camera's precision and other features were met in Oberkochen. The computations permitted additional reserves to be activated, because various limitations did not exist. There was no need, for example, to cover a large image area. The performance of the optics was allowed to drop sharply outside the 7x10 format. Suitability for use in the close range was not required, nor was the camera's behavior in extensive stopping down of any relevance. Full attention could therefore be given to image field flattening, resolution and high contrast with minimum stopping down.

The result of this design work: customized 150mm and 300mm ZEISS Planar® f/4 lenses of outstanding performance peaking at f-stop 5.6. Occasionally, I also use a 75 mm Biogon® f/4.5 lens. Its focal-plane shutter and large bayonet make the camera mechanically suitable for the installation of virtually any type of lens. The 10cm long negatives have quite often been used for the production of enlargements of 100 times and higher for use as permanent decorations.

It certainly becomes clear from the above description that this is not a camera for everyone. Technical know-how and a certain amount of manual skill are required for its control and for maintenance work. This camera of which I built 3 samples is a unique rarity and as good as irreplaceable.

The camera surely does not have any general commercial value commensurate to the investment made in it. For everyone who knows how to handle it, however, it is virtually unbeatable as a tool of maximum practical benefit.

Furthermore I have designed and built a film developing machine that allows development of 70mm-film in length of 60m or more without the films imageside being touched.

There are reports on the camera in the following publications:

"Innovation" The Magazin from Carl Zeiss 6/99 (6 pages)
"Photographica Cabinett" 4/99 (6 pages)
"Von Daguerre bis heute" Abring IV

Albrecht Brugger's e-mail: al-ba@gmx.net