Accessory rangefinders & viewfinders

The classic rangefinder is basically a device that uses a simple optical system to measure the distance from your eye to some object. SLR cameras generally provide an image in the viewfinder that indicates whether or not an image is in focus, and not much more. However, classic rangefinders are based upon basic triangulation and thus are fairly accurate at distances up to 50 feet or so. However, for larger distances and for use with telephoto lenses, their accuracy is very limited due to the limited precision of the mechanical couplings necessary to rotate a mirror or prism. However, "focus indicators" such as that described by Daudin and first used in early SLR cameras such as the Rectaflex make use of the fact that an image is being focused on a plane (usually some kind of ground glass plate). One then finds that the accuracy of focusing actually increases with increased focal length of the lens. Here I limit the discussion to the simple rangefinder designs used in cameras and accessory RF's through to the mid-1950's.

The very need for accessory rangefinders and viewfinders was not felt until the advent of the miniature camera, most importantly the small 35mm cameras first introduced by Leitz in the late 1920's. These cameras were intended to be used by amateur and professional alike and few cameras up to that time incorporated a rangefinder. Larger format cameras could be focused directly using the ground glass surface of plate cameras, or zone focusing could be used which took advantage of the significant depth of field of larger format cameras and lenses with significant depth of field, depending on the experience and skill of the photographer. However, the miniature 35mm camera capable of capturing images with fast shutter speeds and fast lenses also brought the need to more precisely focus the image with a limited depth of field that was often encountered. Leitz offered the first widely used and popular accessory rangefinder in 1928 but many other companies followed their lead bringing to market a broad variety over the next 35 years or so.

Soon after the appearance of the Leica, there appeared easily interchangeable lenses of different focal lengths. This became a great advantage to cameras such as the Leica and Zeiss Ikon Contax lines. However, it also created the need for properly adjusted framing with different lenses over a range of focal lengths. The need for the accessory viewfinder and rangefinder was thus born and many were brought to the marketplace with a wide variety of creative designs, creative designs not only in the mechanical sense but also optical designs. Some fine viewfinders were offered by Leitz and Zeiss Ikon which were surprisingly basic in their design using nothing more than variable framing of a fixed field of view. Other companies such as Kodak and Argus, not normally considered to be comparable to Leitz or Zeiss, produced viewfinders as well as rangefinders of high quality applying optical designs significantly more sophisticated than either of their German competitors. These designs are discussed below in conjunction with a few items from the collection.

There are two basic approaches to focusing: One approach presents two superimposed images of the field of view, one direct and a second from an oblique angle. The distance is then determined when the two images merge into one. A second approach is the split-image rangefinder which presents two images each from different angles, and when they are aligned vertically, the distance and focus can be set. Each has its own advantages and disadvantages, regardless of the optical design that has been used to create them. Neither is particularly superior when it comes to long distances such as when telephoto lenses are employed. The modern use of Fresnel lenses, or Daudin types of optics, create an image that has several components including sharpness of lines (as with simple ground glass plates), as well as dislocation and fragmentation of lines (similar to having multiple split-images), the latter being incorporated primarily in SLR cameras. These are significantly better when telephoto lenses are used.

None the less, the alignment of two or more dislocated but individually clear images is superior to the use of two superimposed images for many reasons. The most simple explanation for this preference would be to consider that how the brain processes images presented to the eye. Without any conscious effort, the eye and brain together will attempt to focus images that are slightly blurred or not completely coincident as in the case of some rangefinders. It has long been known in photomicrography that if one does not quickly focus an image in the microscope (which has a very thin depth of field), then the brain will soon make sharpening the image progressively inaccurate which is the reason why we use large, always sharply defined black frames and lines in the optics. Without such clear references in the visual field, it is very difficult to focus the image of the specimen. Alignment of individual images, small ones such as in split-image rangefinders or SLR viewfinders, is a task that the brain can perform quickly and reproducibly and it is not subject to the unwanted accommodations of the eye and brain. Consequently, one or more dislocated images, each being clearly in focus, is a far more reliable and reproducible way to assess focus rather than asking the brain to determine whether two superimposed images are in alignment.

Kodak produced among the highest quality optical rangefinders and viewfinders that incorporated designs far superior to those employed by other manufacturers including those of Lietz and Zeiss Ikon.

Two Kodak rangefinders are shown here, one produced through the 1930's and into the early 1940's (left), the other produced from the early 1940's through about 1960. Both incorporated not only an excellent split image design, but they provided a third optical image of a distance scale in the same field of view (see above). This unusually sophisticated patented optical design by Mihalyi was based upon an earlier design by John E. Woodbury who patented several coupled range finders between 1914 and 1941.

The Mihaly design adapted Woodbury's three image segments to effectively provide not only a split image of the field, but also the distance scale in the third viewing field segment (see Early Kodak coupled rangefinders). This sophisticated split image design was widely considered to be superior to that of the coincident image design of Leitz which required alignment of two superimposed images. Anyone who has experience using a Leica camera is well aware of how helpful it is to provide some contrast to the second coincident image. Leitz even offered an accessory colored filter to place over one of the rangefinder windows in order to provide such contrast and make focusing easier. Today, most rangefinder focusing designs utilize the split image pioneered by Kodak.

The optical multiple finder shown on the left was introduced c1954 as an accessory for the Retina IIc, IIIc, and IIIC models, all of which had interchangeable front lens elements that provided 35mm, 50mm, and 80mm focal lengths. This accessory finder had two adjustments and a very simple optical design. A rolling knob on top selected either 35mm or 80mm focal lengths even though it only selected one of two alternative blackout frames in a field of fixed magnification. A second dial located on the back could be used to correct for parallax once the cameras rangefinder was focused and indicated the proper distance. It is a wholly unimpressive accessory given its bare simplicity of design.

An additional use for rangefinders was to provide critical focusing for close objects in conjunction with use of auxiliary lenses. These rangefinders not only provided for critical distance measurement, but also the required parallax correction for close focus. The Kodak product introduced for the Retina IIc, IIIc and IIIC models is shown here (left and above). This close range finder and auxiliary lenses were made by Kodak AG between about 1954 and 1963.

The top scale (above) is divided into three ranges that correspond with the particular auxiliary lens. After focusing with the coincident images in the viewing field, the scale then indicates which of three auxiliary lenses should be mounted on the 50mm f/2.8 lens as well as where the camera's rangefinder should be set.

The first Argus viewfinder was a solid and precise instrument that provided three optical magnifications matching the three focal length lenses available of 35, 50, and 100mm, rather than simply providing variable framing at a fixed magnification. The desired magnification was selected by rotating a knob on the right of the finder. A second knob on the left provided parallax correction as determined by the camera's built-in coupled rangefinder. The viewing field was reasonably large and bright though the use of multiple internal lenses led to excessive fogging. Due to the assembly design, the internal optics were not easily accessible for cleaning.

Parallax correction for the Argus variable viewfinder was made separately with a second knurled ring. This design was much better than that of the Nikon viewfinder which used the Leica-type lever at the base mount.

As seen on the right, the Nikon variable viewfinder was similar to that of the later Argus one in design and of comparable quality to that of the Argus. A single rotating ring was used to set the focal length from 35 through 135mm. Since Nikon had quite a few more lenses from which to select, detentes were located at 35, 50, 73, 85, 90, 105, and 135mm. As the Argus, the zoom optics had limited range so the field framing was slightly decreased as one stepped through increasing focal lengths. However, unlike the more ergonomic knurled ring used by Argus, parallax correction was made with a small lever located on the viewfinder's mount. The field of view for both the Nikon and Argus units was virtually identical, however.

Here are two viewfinders produced by ZI in the early 1930's. Each has five turret mounted lenses corresponding to the 2.8, 5, 8.5, 13.5, and 18cm lenses. No parallax correction was provided. Note that one is nickel plated (serial number 3673), whereas the other earlier example was chrome plated (serial number 802). Also, the chrome version incorporated detentes at each position, while the nickel version had no detentes suggesting that it was an earlier design even though the serial number indicates otherwise.

VIDOM

Here are two VIDOM type VF's that were originally designed by Ernst Leitz II and produced from 1933 through about 1940.

These VF's did not incorporate optics to vary the magnification that corresponded to the various lens focal lengths, but rather simply used two L-shaped masks that changed the framing size. They accommodated lenses of 3.5, 5, 7.3, 9, 10.5, and 13.5 cm and the selector ring was continuous variable and did not have click-stops for each focal length. The images were upright but reversed so that as one moved the camera in one direction, the image in the VF moved in the opposite direction, a problem that was corrected in 1940 with the advent of the VIOOH type that used two prisms.

Paralax correction was performed using the lever in the back and the eye piece could be rotated 180 degrees to accommodate different camera orientation. The VIDOM was produced in black and nickel as seen above, black and chrome, all nickel, or all chrome as seen here to the right. There were a number of other variations as well too numerous to mention here.

The all chrome VIDOM was certainly not inexpensive at £4 8.0, equivalent to over $410.00 today. However, the enamel and nickel version was less at £4 5.6 but not by much.

VIOOH

In 1939-40, Leitz introduced the VIOOH type VF which was a significant improvement over the VIDOM. It was not only more compact, but also provided an image that was not reversed and not as challenging to those of us who have eye-hand coordination problems. Again, there were at least 10 variations in the VIOOH including the shape of the body.

Above are two straight bodied versions having different lens options. The earlier example (serial no. 4329) was produced without the threaded nose piece which was used for the TUVOO 28mm adapter. This curiously awkward accessory was the alternative to the Albada-type folding SUOOQ VF that had been introduced earlier in 1934. Although suggesting that it was an after-thought, it did provide a weather-proof 28mm viewfinder which was of particular value during WWII.

Right: The Tower clone of the Lyre shaped VIOOH was produced in Japan in the late 1940's and early 1950's.

Enclosed Albada Types

In 1951, Leitz began to sell dedicated Albada type viewfinders that were entirely enclosed and relatively weatherproof. These were particularly useful on the newly introduced Leica Ic and If (seen on the right) technical models which did not have built-in viewfinders. As shown in two views on the left, the SBOOI model for the 5cm lenses had a modest means of parallax compensation in the form of the little dotted line. However, models for longer focal lengths had parallax adjustments as seen on the SHOOC below.

There were many variations in these viewfinders in terms of engraving styles, presence of a second metric scale, presence of incised finger grips on the barrel and the chromium finish.

Kodak

The first accessory range finder produced by Kodak in the 1930's represents the creative design of two talents. The optical design of both Kodak rangefinders shown here was the product of the work of Joseph Mihalyi. Mr. Mihalyi had a special interest in the design of rangefinders, but he is perhaps best known for the fact that he was the chief designer of the legendary Kodak Ektra camera.

The art deco design of the black rangefinder was contributed by Walter Dorwin Teague. In 1927 Teague began his long career as one of the most influential industrial designers. Soon thereafter Teague was engaged by Kodak to design cameras and accessories. Many if not most so-called art deco cameras produced between 1928 and 1940 by Kodak were the creation of Teague and the rangefinder shown above is one of these designs.

Argus

In 1954 Argus introduced their C-forty-four-R which was a modified C-44 having interchangeable lenses and rapid advance lever. Two accessory viewfinders were provided through 1962, both being very high quality and of a sophisticated optical design (right).

For both the C33 and C44 models, Argus introduced their second version of a viewfinder (right) with continuously variable magnification while simultaneously changing framing to accomplish the field of view for the 35, 50, and 100mm lenses, similar to the Nikon accessory viewfinder seen below.

Nippon Kogaku

Zeiss Ikon

Zeiss Ikon had opted to continue the use of individual lenses on their viewfinder corresponding to the actual field of view for a variety of camera lenses. This design was widely copied by others, in particular Kiev Arsenal who continued to produce Contax II and III model clones through the mid 1980's.

Leitz

There were many types of viewfinders produced by Leitz for the Leica cameras each with different designs as well as variations within any particular design. Here are some of the VF's that have been collected along with the Leica cameras.

An all chrome version of the VIDOM is shown to the right. Serial numbers were not used on the VIDOM types. A short second index line was provided to compensate for the reduced field size when taking close-up photos.

Below: The Lyre shaped body, one of three variations in body shape produced by Leitz. this shape was also produced by Leitz in New York and marketed as the Imarect model during and immediately following WWII. This body was also produced by Nicca in Japan.