A zoom finder with an Albada System comprising, beginning on the object side, a first lens component having positive refractive power, a second lens component having negative refractive power, a third lens component having negative refractive power and provided with a half mirror on a surface of an image side thereof, and a fourth lens component have positive refractive power and provided with a frame on a surface of an object side thereof, wherein said Albada System is constructed by said third lens component and said fourth lens component; said zoom finder with an Albada System is arranged to be zoomed by moving said second lens component; high magnification, a high magnification ratio, a large angle of view and compact size are provided; and various aberrations are properly corrected. The frame may be provided on the optical member arranged in the vicinity of the fourth lens component on the object side thereof. Further, a field frame may alternatively be provided on the optical member and a focusing frame may also be provided on the surface of the object side of the fourth lens component.
A zoom finder can be provided which ensures high magnification and satisfactory view-finding without the need to increase the size. A positive lens which is movable along the optical axis is provided closest to the object side. A negative lens which is movable along the optical axis is provided on the eye-side of the positive lens. Zooming may be accomplished by the zoom finder by moving these lenses along the optical axis. A third lens is provided on the eye-side of the negative lens. The third lens is a negative lens which is fixed and has an eye-side surface which serves as a half-mirror. On the other side of this third lens is a parallel planar plate having an optical frame on one surface which indicates the imaging range. The parallel planar plate may be moved in a direction perpendicular to the optical axis in order to compensate for parallax. A fourth lens which is a fixed positive lens is closest to the eye-side.
An improved zooming viewfinder includes, in order from the object side, a positive first lens group, a negative second lens group that has a zooming capability and which is capable of moving along the optical axis, a negative third lens group that has a half mirror surface on the pupil side, and a fourth lens group that is a positive eyepiece and which has a field-limiting frame on the side the closest to the object. The eyepiece includes, in order from the object side, a positive lens element 4a and a negative lens element 4b.
An Albada zoom finder includes a first lens assembly of positive power, a second lens assembly of negative power, a third lens assembly of negative power and a fourth lens assembly of positive power, arranged in this order from the object side of a camera. An Albada frame is provided on the lens surface of the fourth positive lens assembly on the object side thereof. A reflecting surface is provided on the lens surface of the third negative lens assembly on the viewing side thereof, wherein each of the four lens assemblies is comprised of a single lens. Only the second negative lens is movable as a variable power lens assembly.
A high-zoom-ratio real-image finder is provided with an objective lens system including a first lens unit having a positive power, a second lens unit having a negative power, a third lens unit having a negative power and a fourth lens unit having a positive power. Zooming is performed by moving the second and third lens units always in the same direction. A luminous flux restricting member is integrated with a holder for the second lens unit. A zoom strobe unit moves integrally with a holder for the third lens unit.
A finder optical system provided separately from a photographic lens having a variable magnification portion comprises, from front to rear, an objective lens unit having a first variable magnification portion, a Porro prism and an eyepiece lens unit having a second variable magnification portion. And, a first magnification change of the first variable magnification portion is achieved in association with the variable magnification portion of the photographic lens, and a second magnification change of the second variable magnification portion is achieved in association with trimming shot information.
