Leica Camera Ag

Stefan Roth

Sigrun Kammans

Dietmar Stuible

Peter Karbe

Kathrin Keller

A lens system with a fixed focal length includes five lens groups. The five lens groups include a first lens group, a second lens group configured as a focusing front group, a third lens group having a negative refractive power, a fourth lens group configured as a focusing back group, and a fifth lens group. The fifth lens group has a positive refractive power that is arranged in a stationary manner relative to an imaging plane in a lens barrel and both the focusing front group and the focusing back group are movable jointly relative to one another and to the lens groups arranged in a stationary manner in order to focus the fixed focus length lens system on objects at different object distances.

Lens having a fixed focal length and constant overall length for auto focus applications including five lens groups of ++--+, -++-+, -+++-, -++--, +-+--, +-++- or ++++- refractive powers

A wide-angle objective in accordance with the invention comprises, in an order from an object-side end to an image-side end, a front group of total positive refractive power having at least four lenses; a middle group of total positive refractive power having at least three lenses; and a rear group of total positive refractive power having at least three lenses, wherein the quotient of the focal length of the front group and the total focal length of the objective amounts to between 2.28 and 2.79, the quotient of the focal length of the middle group and the total focal length of the objective amounts to between 3.02 and 3.69, and the quotient of the focal length of the rear group and the total focal length of the objective amounts to between 3.50 and 4.29.

Wide-angle photographic objective

A lens with a fixed focal length includes five lens-element groups, a first front lens-element group, a second lens-element group, a third lens-element group, a fourth lens-element group, and a fifth back lens-element group is arranged in a stationary manner. Relative to an imaging plane in a lens barrel and both the focusing front group and the focusing back group are movable jointly relative to one another and to the lens-element groups arranged in a stationary manner in order to focus the lens on objects at different object distances.

Lens having a fixed focal length and constant overall length for auto focus applications

What is described is a modified retrofocus-type wide-angle lens, with, as seen from the object, a front group (G) with negative refractive power, a first rear group (Gh) with positive refractive power displaceable along the optical axis for focusing purposes and a second rear group (Gh) with positive refractive power facing an image plane.

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Lahnau, Germany

Stefan Roth