Photographic Optics: Including the Description of Lenses and Enlarging Apparatus. Translated from the French |
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Common terms and phrases
achromatic achromatised adjustible mirror angle aperture aplanatic astigmation bi-convex blurs of diffraction centimètres chemical focus chromatic aberration circle colour combination concave face condenser considerable convergent lens convergent meniscus crown-glass curved cut the axis Dallmeyer depth of focus diameter diaphragm direction disc divergent lens employed enlarged image enlarging apparatus enlarging lens equal field fixed flint-glass focal distance focal length focal plane formula frame give glass globe-lens ground-glass heliostat horizontal inches incident ray index of refraction landscapes lenses less light margins mètres millimètres mounting necessary negative lens non-aplanatic objectives obtained optical apparatus optical centre opticians orthoscopic parallel perpendicular placed plano-convex plano-convex lens plate position principal axis principal focus prism proof radiating point radii of curvature radius rays emergent reflected refracted ray reproduced ROSS'S screw sharp image single objective small diaphragm solar camera solar rays spherical aberration thickness triplet vertical violet
Popular passages
Page 8 - When a ray of light passes from one medium to another, it is refracted so that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities in the two media.
Page 8 - ... the ratio between the sine of the angle of incidence and the sine of the angle of refraction is a constant, depending only upon the nature of the two media.
Page 223 - ... they should have been previously cut in the house, from the pattern given by one of the cards that had been mounted and cut in the instrument. In mounting the instrument in place, the points to attend to are, (1) that it shall be level as regards east and west, (2) that the axis of the ring shall be inclined to the horizon at an angle equal to the latitude of the place...
Page 163 - I/; to properly adjust the negative, J, so that its enlarged image is sharply formed on a screen, placed at a distance and perpendicular to the optical axis of the apparatus, and, lastly, to substitute for the screen a sheet of sensitive paper or other Photographic surface. Considerable improvements have been made in the Solar camera of Woodward, notably those by Dr. Monckhoven, who, to cure the evils arising from the aberrations of sphericity, whereby the various transmitted rays do not arrive at...
Page 57 - Hence the magnification, as thus defined, is measured as before by the ratio of the size of the image to that of the object, when the image is at the least distance of distinct vision.
Page 163 - An adjustible mirror, AB, is so placed and regulated as to throw the sun's rays through the condenser, I, and the enlarging lens, L. The management of the apparatus is very simple. It is sufficient to place the part EHBA of the solar camera in an opening in a darkened window, to communicate by means of the adjusting screws, B and D, the movements necessary for keeping the solar rays always reflected in the same direction...
Page 34 - Principal Axis is the straight line which joins the centres of curvature of the spherical surfaces of a lens, or if one surface is plane, the principal axis passes through the centre of curvature of the spherical surface, and is perpendicular to the plane surface.
Page 161 - I (fig. 75), called the condenser, at the principal focus of whic.h an achromatic objective, L, is fixed. A mirror, AB, throws the solar rays, rr, on the condenser, I ; and the negative, J, moveable by means of a rack, K, is placed between the two lenses at a distance which varies with that of the screen on which the image is to be formed.
Page iii - Photographic Optics: Including the Description of Lenses and Enlarging Apparatus. By D. VAN MONCKHOVEN, Ph.D. Crown 8vo. cloth, with more than 200 illustrations, price 7s. 6d.
Page 65 - The chromatic aberrations. The focal length of a lens is a function of the index of refraction of the material of which the lens is composed. Since the index of refraction of all optical substances varies with wave length, the focal length of a lens is different for different colors. As a consequence, a single lens forms not merely one image of an object, but a series of images at varying distances from the lens, one for each color...