to alter the distance between the lenses, letting the stop keep the ratio of its distances from them. This alteration prevents the doubly reflected rays from being brought to a focus on the sensi- tive plate. Focal Length. — The focal length of a simple lens is the distance at which it brings… … through the centre of the screen, and turn the camera on its screw so that first one and then the other lateral limit falls on the vertical line, and in each position draw a line on the board along the edge of the camera. These lines give the angle of view. Let OA, OB be these lines ; take OA = OB,…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
