1. Field of the Invention
This invention is related to a camera for close-up photography using a photo-ranging system to insure that the subject to be photographed is properly focused. The ranging system is used in combination with a selected one of a plurality of fixed focus lenses mounted at the front of the camera.
2. Description of the Prior Art
Cameras having the capacity to take close-up photographs are not new. An example of a camera used for close-up photography is the Acmel Macro Auto V6 camera manufactured by Acmel Corporation of Tokyo, Japan which involves a highly complicated system involving focal beams and a plurality of detachable lenses for different focal lengths. Each detachable lens is designed for a single subject distance. The resulting camera serves its purpose but is altogether too complicated for easy use by a camera operator. It is both bulky and heavy, weighing about 41/2 pounds.
The use of converging light beams from a camera to determine a proper subject to camera distance is old art as disclosed in U.S. Pat. No. 3,416,426 which is specifically incorporated herein by reference. The theory disclosed therein and in other literature provides a light source reflected from spaced apart mirrors through a lens board to converge at the subject of the photograph. This technique is useful where several parameters remain constant, in particular, one of the constants is flash photography. With flash photography the duration of exposure is set and the only other variables are the exposure aperture and the focus of the lens.
U.S. Pat. No. 4,777,501 discloses a single pair of laser ranging lights of different wavelengths mounted to project converging light beams at the focal point of a single fixed focus exposure lens of the associated camera.
U.S. Pat. No. 4,914,460 discloses a single pair of light sources each of which projects a plurality of light beams in a particular pattern. The pattern is displayed on a surface which allows an observer to determine the topography of the surface and its distance from an associated camera. The camera is mounted equidistant between the two light sources.
U.S. Pat. No. 5,142,299 discloses an underwater camera mounted between a pair of light sources. The light sources project light beams to converge at the focal point of a single fixed focus lens system of the associated camera.
What is missing from the prior art is a camera for close-up photography having more that one focal length available to a user combined with a plurality of ranging systems to insure proper focus of the subject.