Wide-angle slip-on viewfinder on rangefinder cameras for photographic recordings with different focal lengths

US7706682B2 · kind B2 · utility

Assignee

• Leica Camera AG · DE

Inventors

• Kathrin Keller · Waldgirmes, DE
• Uwe Reinstädtler · Reiskirchen, DE

Key dates

• Filing date: Aug 2, 2007
• Grant date: Apr 27, 2010
• Expiry date: Oct 30, 2028

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B23/14
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Described is a wide-angle slip-on viewfinder (1) on rangefinder cameras for analog and digital wide-angle recordings of different image recording formats with lenses of different focal lengths, comprising three lens groups (LG1, LG2, LG3), a frame/mask unit (10) and a partially transmissive prism cube (8) which is designed as a combination element, wherein, on the light entrance side (4) in the viewfinder beam path (9), a first lens group (LG1) has a negative refractive power and the second and third lens groups (LG2, LG3) have a positive refractive power, wherein the second lens group (LG2) is composed of a first lens (L3) arranged downstream of the first lens group (LG1) and a second lens (L4) arranged on the light exit side (7) and the partially transmissive prism cube (8) is arranged between the lenses (L3, L4) and the third lens group (LG3) is arranged in a mask imaging beam path (11) which is at right angles to the viewfinder beam path (9) between the frame/mask unit (10) and the partially transmissive prism cube (8).