Patent ID: 8564880

Claim:
An afocal zoom system for a microscope comprising: a plurality of lens groups including a first lens group disposed in the direction of a beam path passing through the zoom system from an object; and a first shutter having a variable diameter opening for controlling a depth of focus of a microscopic image of the object, wherein the first shutter is fixedly disposed in front of the first lens group or is disposed on a lens group in the plurality of lens groups; wherein the plurality of lens groups includes a last lens group disposed in the direction of the beam path passing through the zoom system from the object, and the afocal zoom system further comprises a second shutter arranged after the last lens group; wherein the second shutter is configured to be varied to control a depth of focus of the image of the object at low to medium magnifications of the afocal zoom system; and wherein the first shutter is configured to be varied to control the depth of focus of the image of the object at medium to high magnifications of the afocal zoom system.