Optics of photography : on a new process for equalizing the definition of all the planes of a solid figure represented in a photographic picture / by A. Claudet.

  • Claudet, A. (Antoine), 1797-1867.
Date:
[1866?]
Catalogue details

Licence: Public Domain Mark

Credit: Optics of photography : on a new process for equalizing the definition of all the planes of a solid figure represented in a photographic picture / by A. Claudet. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    <oh’^o^k foy -fAHO-LLA From the Philosophical Magazine for September 18GC, OPTICS OF PHOTOGRAPHY. ON A NEW PROCESS FOR EQUALIZING THE DEFINITION OF ALL THE PLANES OF A SOLID FIGURE REPRESENTED IN A PHOTOGRAPHIC PICTURE. ONE of the greatest deficiencies of photography in the repre- sentation of solid figures is the impossibility of obtaining a well-defined image of all the various parts situated on different planes; for it is well known that the best object-glasses can give a sharp image only for the plane in focus; the images of the objects situated before and behind are more and more con- fused as they are more and more distant from that plane. To obviate this, or rather to equalize the effect to a certain degree, it is customary to reduce as much as possible, by means of diaphragms, the aperture of the lens. The object of such diaphragms is to cut off all the oblique rays, and to employ only the rays which emerge from the lens at the least angle possible. It is evident that when the rays are emerging from the centre of the lens, they follow a course so nearly parallel that any equal points of the object on various planes are included between spaces not varying much in size; so that although these points are distant from the plane which is represented at the mathematical focus with the greatest definition, they form their image within a circle of confusion so near the circle of definition that the eye * Read at the British Association, Nottingham Meeting, 186(5. BY A. CLAUDET, F.R.S.*