Stereoscope

History

Stereoscope of Wheatstone

The first stereoscope is due to the famous English physicist at the same time Charles Wheatstone, which deposited in 1838 a report with the Royal Academy, as the first known stereoscope, and accepted for that Royal Medal in 1840. This stereoscope comprised two mirrors with 90° which laterally returned the glance towards two especially prepared stereoscopic drawings. Then the principle was applied to photography.

There exists an alternative in the shape of “W”, with three angles with 60°.

Stereoscope of Brewster

The second type of stereoscope is indebted to the scientist and inventive David Brewster, which had the idea to substitute for the mirrors of the lenses, prismatic or not, according to the format of the sights to be observed. The stereoscope takes the aspect then that we know to him still today: a case in cabinet work, two eyepieces, a system of development, frosted glass.

Stereoscope of Holmes

This stereoscope, which dates from the years 1850, was intended for the observation of the stereoscopic charts, then in full rise. It included/understood two prismatic lenses inserted in a characteristic visor, as well as a wooden support to hold the stereo chart. A handle, at the lower part, facilitates the gripping of the unit. This type of stereoscope will remain in manufacture during one century. It is an American object above all, although it is often affublé of the name of “Mexican stereoscope”! …

The stereoscopes with prism S of the French grocer Julien Damoy are among the very good ones.

Stereoscopes of the Beautiful Time

Stereoscopes with hand

The development of the apparatuses with plates of the years 1900 asked for the creation of stereoscopes renovated compared to the precedents, and answering the new requirements of the many amateurs followers of the stereoscopy. One thus built Visionneuse S less elaborate than the preceding ones from the point of view of the cabinet work (good-bye, contours and the Marqueterie!), but well more with regard to mechanics (beautiful slopes of development with Toothed rack S in Brass, variable spacing of the Ocular S) and optics (eyepieces of large diameter, sometimes achromatic with two lenses). There existed also english bonds and cheap, however sufficient for a satisfactory observation.

One meets commonly stereoscopes of the years 1900-1940 for the two standard sizes at the time: 6 X 13 cm and 45 X 107 Misters.

Stereoscopes of table

Optically, they are similar to the precedents, but they are this time true pieces of furniture containing a mechanics with chain or mobile drawers, making it possible to charge a considerable number of plates (between 25 and 50 according to the models) and to change sight without leaving the eyepieces of the eyes.

Stereoscopes of today

Eyepiece stereoscopes

They are usually intended for the examination of the couples of Diapositive S:

those of the Fifties, often American, with case out of most recent moulded matter and built-in lighting (small standard bulb flashlight),
and, built with the small file by craftsmen or skilful amateurs, made for customers of raftered stereoscopists, having moreover the taste of the experiment. One pushes there the improvements until the last limits: optics with four treated lenses, lens of field, lighting with fluorescent Tube, lamps Halogenous S or with very powerful white electroluminescent diodes…
beside that, of the stereoscopes more modest, and even good market, often very out of plastic, including the lenses, and deprived of lighting…

Prism or mirror stereoscopes

They were created as from the years 1990 for the examination of sights on paper, either placed side by side, or one above the other. Their current success comes from the explosion from numerical, the traditional one and excel eyepiece stereoscope not being, currently in any case, compatible with this novel method.

Stereoscopes for the air sight test

They are instruments of professional use, including/understanding eyepieces and systems of mirrors or prisms, well-known of the geographers and all those which have to study the relief of the Earth. The couples of air sights are placed on a table, and the stereoscope, posed just above the common parts of the images, allows examination the vertical, not always easy for the beginners.

The era of numerical and the stereoscope of tomorrow

The digital image in stereophony can be observed on the screen of the computer or in pulling paper by means of the systems with mirrors or prisms seen previously. What currently misses, it is an eyepiece stereoscope for direct examination of the numerical sights on bill-poster. One could imagine some 6 cm broad screens (adapted to the spacing of the eyes human) and equipped with million luminescent elements individually unperceivable. What is science fiction today could become reality in the next years.

External bonds

French Stereophony-Club
The Stereoscope and Stereophony-photography

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