The stereoscopic manual / by W.I. Chadwick.

  • Chadwick, William Isaac.
Date:
[between 1890 and 1899?]
Catalogue details

Licence: Public Domain Mark

Credit: The stereoscopic manual / by W.I. Chadwick. Source: Wellcome Collection.

    18/72 (page 14)
    APPARATUS -C AMERAS. Having devoted the first two chapters to the subject of binocular visions and the theory of the stereoscope, we must now proceed to the consideration of some practical points in connection with the production of stereoscopic photographs. The early stereoscopic photographs were taken by single camera, fitted with only one lens. They were generally pro- vided with an extra baseboard and an arrangement of parallel levers, or something of the kind, by means of which the camera was moved a few inches (or as much as was considered necessary) between the first and the second exposure, it being necessary, as has already been explained, that for stereoscopic effect two dissimilar pictures, taken from different standpoints, are required. There are many objections to the single camera, and it is claimed that the late J. B. Dancer, of Manchester, was the first to construct a twin camera provided with twin lenses. However that may be, it is quite certain that he did construct some of the earliest of these improved instruments, and although they were heavy and clumsy affairs compared with others of a more recent date, the principle involved was the same. The earlier twin cameras were constructed without bellows bodies, being simply plain wooden boxes with a central wooden division, and when two lenses were not obtainable, one was made to answer the purpose by a sliding front board, shifting the lens from one side to the other between the exposures, as in the old single camera. Sometimes this method is resorted to nowadays, and it answers well enough when the conditions are favourable, but for animated nature or objects in motion, instantaneous effects, &c., two lenses must be used.