A First Book of the Lens: An Elementary Treatise on the Action and Use of the Photographic LensHazell, Watson, and Viney, 1901 - 170 pages |
Other editions - View all
A First Book of the Lens: An Elementary Treatise on the Action and Use of ... C. Welborne Piper No preview available - 2008 |
Common terms and phrases
achromatic adjusted anastigmatic angle of definition angle of incidence approximately astigmatism axial rays blur camera chromatic aberration circle of confusion colour coma component lenses concave conjugate foci convergent convex corrected covering angle crossing-point curvature definition volume depth of definition depth of field deviation diaphragm direct pencils distortion divergent doublet effective aperture emergent pencil equal error extra-focal distance flare focal distance focal length focal power focussing focussing-screen formulæ fractional diameter front glass greater hence hyperfocal distance illumination image points incident pencil infinite distance infinity mark intensity landscape lens measured meniscus meniscus lens method negative lens nodal contact nodal space node of admission object oblique pencils parallel pinhole plate positive lens primary plane principal axis principal focus produce ratio aperture rectilinear refractive index refractive surfaces relative exposure scale screen secondary plane separation shown in fig single lens stop supplementary lens telephoto lens true image varies wavefront wide angle
Popular passages
Page 16 - 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 17 - If the surfaces are parallel the angle of incidence at the second surface is equal to the angle of refraction at the first...
Page 11 - ... are magnificently exposed, except for thin deposits of talus. Attention was first directed to the contact by its unusual shape; instead of being flat, jaggedly rough, or gradational, it is a sharp line, but wavy, in smooth flowing curves, the "waves" having a depth of 6 inches to 1 foot, roughly, from the top of the crest to the bottom of the trough. The appearance is precisely similar to a cross-section of a glacially gouged rock surface covered with soil.
Page 16 - ... the index of refraction is equal to the sine of the angle of incidence divided by the sine of the angle of refraction.
Page 100 - Exposure is thus determined by the ratio of the diameter of the aperture to the focal length of the...
Page 92 - ... the ratio of the linear dimensions of the image to those of the object.
Page 120 - The effective /-number is equal to the focal length of the lens divided by the...
Page 29 - EKCN the magnifying power also to be equal to the ratio of the distance of the image from the lens to the distance of the object from the lens — l. Since A' for best vision is equal THE COMPOUND MICROSCOPE to 25 centimeters, an object placed 2.5 cm.
Page 11 - Going back to our simile of the ripples on the pond, it is evident that the size of the ripples depends on the size of the stone, and the force with which it strikes the water, for a small pebble will raise only small ripples while a large rock will produce big waves.
Page 165 - APPROXIMATE INFINITY FOR LENSES OF VARIOUS FOCAL LENGTHS. By C. WELBORNE PIPER, from " The First Book of the Lens." By focussing accurately on distances not less than those given, we ensure that the focussing-screen is within ^5, 5J5, ^Jj, or, rj^jo in.