Viewfinder device

A zoom viewfinder comprising:

• an objective lens;
• an optical unit for converting a viewfinder image formed by said objective lens into a non-inverted erect image;
• and
• an eyepiece lens unit;
• said objective lens including;
• a first lens unit of negative refractive power;
• a movable stop for blocking a peripheral portion of an on-axial bundle of light rays forming the image;
• and
• a second lens unit of positive refractive power
• said first lens unit, said movable stop and said second lens unit being arranged in that order from an object side;
• said first lens unit, said movable stop and said second lens unit being movable toward the object side while reducing their respective separations, thereby effecting zooming from a wide-angle end toward a telephoto end.

A viewfinder device arranged to relay an optical path of an objective lens, comprising:

• a first prism unit;
• and
• a second prism unit;
• said first prism unit including:
• a surface 1-1 having a positive power for entrance of light from the objective lens into said first prism unit;
• a surface 1-2 for totally reflecting the light entering from said surface 1-1;
• and
• a surface 1-3 for reflecting the light reflected by said surface 1-2;
• said second prism unit including:
• a surface 2-1 for entrance of the light reflected by said surface 1-3;
• a surface 2-2 for reflecting the light entering from said surface 2-1;
• and
• a surface 2-3 for reflecting the light reflected by said surface 2-2;
• said surface 2-1 reflecting the light reflected by said surface 2-3;
• and
• the objective lens forming an image between said first prism unit and said second prism unit,
• whereby the following condition is satisfied:
• 0.2<f.sub.w /f.sub.e <2
• where f.sub.w is the focal length of the objective lens in a wide-angle end, and f.sub.e is the focal length of an eyepiece lens.

A viewfinder device arranged to relay an optical path of an objective lens, comprising:

• a first prism unit;
• and
• a second prism unit;
• said first prism unit including:
• a surface 1-1 for entrance of light from the objective lens into said first prism unit;
• a surface 1-2 for totally reflecting the light entering from said surface 1-1;
• and
• a surface 1-3 for reflecting the light reflected by said surface 1-2;
• said second prism unit including:
• a surface 2-1 for entrance of the light reflected by said surface 1-3;
• a surface 2-2 for reflecting the light entering from said surface 2-1;
• and
• a roof type surface 2-3 for reflecting the light reflected by said surface 2-2;
• said surface 2-1 reflecting the light reflected by said surface 2-3;
• and
• the objective lens forming an image between said first prism unit and said second prism unit, and said roof type surface 2-3 reflecting the light in the direction of a short side of the view field,
• whereby the following condition is satisfied:
• 0.2<f.sub.w /f.sub.e <2
• where f.sub.w is the focal length of the objective lens in a wide-angle end, and f.sub.e is the focal length of an eyepiece lens.

A viewfinder device arranged to relay an optical path of an objective lens, comprising:

• a first prism unit;
• and
• a second prism unit;
• said first prism unit including:
• a surface 1-1 for entrance of light from the objective lens into said first prism unit;
• a reflecting surface 1-2 for reflecting the light entering from said surface 1-1;
• and
• a reflecting surface 1-3 for totally reflecting the light reflected by said surface 1-2;
• said second prism until including:
• a surface 2-1 for entrance of the light reflected by said surface 1-3 into said second prism unit;
• a reflecting surface 2-2 for reflecting the light entering from said surface 2-1;
• and
• a reflecting surface 2-3 for reflecting the light reflected by said surface 2-2;
• said surface 2-1 reflecting the light reflected by said surface 2-3;
• and
• the objective lens forming an image between said first prism unit and said second prism unit, and the objective lens having a substantially telecentric characteristic,
• whereby the following condition is satisfied:
• 0.2<f.sub.w /f.sub.e <2
• where f.sub.w is the focal length of the objective lens in a wide-angle end, and f.sub.e is the focal length of an eyepiece lens.