Camera viewfinding system
AssigneeOptigon Research & Development Corporation
InventorsJacob Moskovich, Gary E. Wiese, Richard M. Altman, Thomas D. McLaughlin
Life of this patent
Estimating the term…
Abstract
A viewfinder system for a through-the-lens viewing camera which includes a focusing screen, a field lens, a prism, and an eyepiece is disclosed where the field lens is positionable in accordance with the position of the exit pupil of the objective lens and the eyepiece is positioned in accordance with the position of the field lens. Negative optical power is introduced between the field lens and the prism, and the prism design substantially reduces the size of the prism without sacrificing viewfinder brightness.
Claims12
A viewfinder system for a single lens reflex camera having a defined image frame comprising a substantially rectangular focusing screen of dimensions essentially equal to the image frame of the camera, a field lens, a pentaprism having substantially rectangular entrance and exit surfaces of essentially the same width, and reflecting surfaces therebetween, and an eyepiece disposed behind said exit surface, all on an optical axis which is changed from normally vertical to normally horizontal in said prism, a lens of negative power disposed between said field lens and said entrance surface, said entrance surface having an area substantially less than the area of said screen, said exit surface having a height of at least 0.70 of the height of said entrance surface.
A viewing system for a through-the-lens viewing reflex camera having the ability to accept a plurality of objective lenses, said viewing system comprising a focusing screen, a field lens, a prism having entrance and exit surfaces with two reflecting surfaces therebetween to change the optical axis of said system from vertical to horizontal, and an eyepiece all on an optical axis coincident with the axis of the objective lens, a lens of negative power disposed between said field lens and said entrance aperture, said entrance surface being dimensioned substantially smaller than the focusing screen, and the length of the optical axis in said prism being greater in the vertical than in the horizontal.
Dependencies are inferred from the claim text.