A stereomicroscope of the Greenough type includes a first monocular microscope and a second monocular microscope, which define a first beam path and a second beam path, respectively, wherein the first and second microscopes are arranged at a convergence angle to one another and comprise magnification systems for producing equal magnifications which can be varied synchronously with one another. At least one optical element in the first microscope has a different optically effective diameter compared to at least one corresponding optical element in the second microscope.