When introduced a small wheel was fitted, in 1930 the dial was larger.

This is an upright model with a shoe fitting. The fitting has the early shape of a disc with two segments cut off. The price was 36/-.

Early versions used a slide bar to change the distance, later c. 1928, a wheel was used, the finish also changed from plain metal to black crackle paint.

This model is screwed on to the camera or used in the hand, there is no accessory shoe fitting. The price was 32/6.

A curious rangefinder designed for use on a finger for which there is an elastic strip. The meter is very large compared to those that fit in an accessory shoe. Two rubber plugs can be removed allowing adjustment to the fixed mirror. Also produced in metres and with an un-painted metal body. This example comes in a box having a yellow label.

Similar to the previous example but the box has a white label with black and red printing rather than a yellow label.

This comprises a small telescope, the inner tube pulls out on an Archimedean thread to focus. Two distinct versions were produced, the first of around 1900 used a ground glass on which the subject was focused, from around 1902 the ground glass was removed leaving a conventional telescope.

This is an unusual device that combines a rangefinder with a variable focus 'close-up' lens. The device clamps to the front of the camera lens which is set to infinity, focusing is by altering the separation of the lenses in the focorect, the movement is coupled to the rangefinder. Produced in two sizes - standard to fit lenses of 27 - 37 mm diameter and M to fit lenses of 23 - 32 mm diameter. In Britain the focorect was distributed by Johnsons, the M model cost £18.1.5.

This simple device attaches to a camera via the accessory shoe to provide a large waist-level screen and focusing lens, interchangeable masks allow for different film formats.

This is a conventional direct-vision finder with a single negative lens and alignment post, at the rear of the finder a frame is hinged so that it remains vertical when the finder is tilted, to this frame a second frame is attached that will remain horizontal. The finder is levelled by aligning the edge of the horizontal frame with a centre line engraved on the lens. To use as a telemeter the finder is tilted downwards so that the pointer aligns with the centre line on the lens and the base of the subject, the horizontal frame will then point to a value on the distance scale engraved on the lens above the centre line.

The finder was supplied with three masks to fit behind the lens for different angles of view, a mirror for use at waist-level could be attached behind the pointer.

There were two slightly different versions, the first (the example shown here) is depicted in the British Journal Almanac of 1908, in the 1912 issue it is described as 'improved' and that a patent has been applied for.

The drawing of the second version shows the pointer to be suspended from the top of the rear section rather than the bottom. Its use as a telemeter is slightly different: the finder is levelled by ensuring the horizontal frame aligns with the centre line of the lens, the base of the subject is then observed against the distance scale engraved on the lens. Two scales were engraved, one for eye-level use the other for use at waist-level.

As a finder and a level this instrument works well, it is less successful as a telemeter as the strong negative lens makes the numbers on the glass difficult to read.

With the increasing use of hand cameras where focusing on a ground glass screen was impossible or inconvenient, separate distance meters came to be used. Originally these were called distance meters or telemeters, the term rangefinder applied to the 'two position' optical devices was used a few years later. Some common arrangements are listed below.

Subject Angle (Declination)

Standard Subject Size

Focusing Tube

Optical, 'Two Positions'

• Woodbury 1914

  Two fixed mirrors are used. The image from one is deflected by a small amount by a lens combination, in the neutral position the deflection produced by the lenses is zero. The positive part of the lens combination remains fixed to the baseboard, the negative lens (and mirrors, camera lens, front standard etc.) move forward and back along the baseboard so altering the deflection produced by the lens combination.⁵

• Swing Mirror

  The subject is viewed by two separated mirrors. One mirror swivels changing the angle of the reflected image. A very popular construction as it is easy to manufacture. Used on the Contax 1.

• Swing Prism

  A prism is used in place of the mirror. Used in the Leica camera.

• Rotating Wedge

  Two fixed mirrors are used. In front of one mirror two shallow prisms are arranged, these rotate in opposite directions and so change their deflection and the line of sight. This form requires greater movement to cover the focusing range than the swing prism type, allowing finer movement and greater accuracy. Another advantage is that the prisms need not be located next to the mirror. Used on the Super Ikonta, 1934, where the prisms were mounted on the front standard, a common wheel moved the lens and the prisms.⁶

• Swing Wedge

  Two fixed prisms (or similar) are used. In front of one there are two cylindrical lenses, in the neutral position there is no deflection. By swinging one of the lenses a prism of varying angle is formed. Used on the Contax 11 camera, 1936. Rather than two air-separated mirrors or prisms, Zeiss favoured a solid glass rhomboid.⁷

• Bantam Special

  Two fixed prisms are used. In front of one, and attached to the front standard, is a lens that moves laterally. As the camera lens is rotated for focusing a cam moves the rangefinder lens parallel to the rangefinder base. A further development of this was to incorporate the lens behind the prism inside the camera housing. The images are considerably magnified by the rangefinder lens, a similar lens in the path of the secondary image and the eyepiece lenses. The Porro prism close to the eyepiece erects the two images. Developed by Joseph Mihalyi.⁸

• Leica M2

  The M series used a swivelling lens with the movement coupled to rear of the camera lens. The rangefinder and view-finder were combined in a single window, suspended frames were illuminated from a dedicated window.

• Split Field

  The two images are displayed one above the other, as the rangefinder is altered one of the images will move. Typically the mirror or prism in front of the eyepiece has part of its surface clear, the rest is silvered to reflect the 'second image'. The field may be split horizontally or just a middle section may be silvered.

• Double Image

  Part or all of the mirror is semi-silvered giving a double image. Usually the two images are coloured to increase their contrast, this was either by introducing filters or using a different reflective coating to the mirrors.

Rangefinders Built into Cameras

On miniature or solid bodied cameras where the lens is directly attached to the camera body the rangefinder could be coupled to the lens movement by resting a lever, which controlled the rangefinder movement, on the rear of the lens.