Movable reflecting mirror for single lens reflex camera

A camera comprising:

• (A) picture-taking optics including a lens for transmitting picture-taking light along and around a first optical axis which is the lens axis and onto a film plane of said camera;
• (B) viewfinder optics;
• and
• (C) a mirror movable between a first position wherein said mirror is at an angle with respect to said first optical axis, intercepts picture-taking light transmitted by said picture-taking optics before it reaches said film plane and reflects said picture-taking light toward said viewfinder optics and a second position wherein said mirror is removed from said first optical axis and permits said picture-taking light to reach said film plane, said mirror including:
• (1) an optically transmissive member having a front surface and a rear surface which are partially reflective;
• (2) reflecting means disposed on said front surface of said member for reflecting substantially all of the picture-taking light incident thereon;
• and
• (3) light transmitting openings formed in said reflecting means, the size and spacing of said light transmitting openings being selected such that picture-taking light, which is generally concentrated around the first optical axis by the picture-taking optics, but which also is dispersed around the first optical axis, is transmitted through said openings and some of the transmitted light is reflected by said rear surface of said member while none of that reflected light refracts through said front surface of said member toward said viewfinder optics and the size of the openings is also selected so that diffracting phenomena are avoided.