View finder system for a single lens reflex camera

A view finder system for a single lens reflex camera associated with a lens barrel having an objective lens and a plurality of photographing information indicators mounted thereon in different locations, comprising:

• a focusing screen on which an image of an object to be photographed is formed by said objective lens;
• an eye-piece;
• a pentagonal roof prism having a bottom face optically facing said focusing screen, two roof faces, a front reflecting face, an exit face optically facing said eye-piece and a front non-reflecting face, and directing light from said focusing screen to said eye-piece to provide the image of the object in a field of the finder;
• a sub-prism having an entrance face, a reflecting face and an exit face cemented to the front non-reflecting face of said pentagonal roof prism, wherein said entrance face faces upward;
• a mirror positioned above said indicators and said sub-prism, and optically facing the entrance face of said sub-prism;
• and
• means for moving said mirror which supports said mirror in a tilted manner so that the angle of the mirror is varied stepwise to face a desired one of said indicators, so that a light beam from the desired indicator incident upon the mirror is thereby directed through the entrance face to the reflecting face of said sub-prism and thereby directed through the exit face of said sub-prism cemented to the front non-reflecting face of said pentagonal roof prism directly in a direction of the exit face of said pentagonal roof prism to provide an image of the desired indicator in the field of the finder.

A view finder system for a single lens reflex camera associated with a lens barrel having an objective lens and a plurality of photographic information indicators mounted thereon in different locations, comprising:

• a focusing screen on which an image of an object to be photographed is formed by said objective lens;
• an eye-piece
• a pentagonal roof prism having a bottom face optically facing said focusing screen, two roof faces, a front reflecting face, an exit face optically facing said eye-piece and a front non-reflecting face, and directing light from said focusing screen to said eye-piece to provide the image of the object in a field of the finder;
• a sub-prism having an entrance face, a reflecting face and an exit face cemented to the front non-reflecting face of said pentagonal roof prism, wherein said entrance face faces upward;
• a mirror positioned above said indicators and said sub-prism, and optically facing the entrance face of said sub-prism;
• a deflector prism;
• and
• means for moving said deflector prism across an optical path between said sub-prism and the indicators so as to selectively direct a light beam from a desired indicator to said mirror, so that the light beam from the desired indicator incident upon the mirror is directed through the entrance face to the reflecting face of said sub-prism and also directed through the exit face of said sub-prism cemented to the front non-reflecting face directly in the direction of the exit face of said pentagonal roof prism to provide an image of the desired indicator in the field of the finder.

A view finder system for a single lens reflex camera associated with a lens barrel having an objective lens and photographic information indicating means mounted thereon, comprising:

• a focusing screen on which an image of an object to be photographed is formed by said objective lens;
• an eye-piece;
• a penta-prism-type reflection prism having a bottom face optically facing said focusing screen, two roof faces, a front reflecting face, an exit face optically facing said eye-piece and a front non-reflecting face, and directing light from said focusing screen to said eye-piece to provide the image of the object in the field of the finder, said penta-prism-type reflection prism further having a rear reflecting face being located at a rear portion of the penta-prism-type reflection prism and facing both the front non-reflecting face and the front reflecting face;
• auxiliary optical means optically coupled to the front non-reflecting face of said penta-prism-type reflection prism, said auxiliary optical means facing said indicating means and directing a light beam from said indicating means through the front non-reflecting face directly to the rear reflecting face of said penta-prism-type reflection prism so that the light incident upon the rear reflecting face is therefrom reflected to the front reflecting face and therefrom reflected to the exit face of said penta-prism-type reflection prism to provide an image of said indicating means in the field of the finder.