The Stereo Microscope

This is a binocular microscope in which the specimen under examination is viewed independently by each eye from two different angles. It is analogous to a pair of binoculars, or two independent compound microscopes set side by side at a converging angle of 15 degrees. The first such instruments, the Greenough design, had two sets of optics -- two objective lenses and two eyepieces. The paired objectives, mounted on dovetail slides, were interchangeable. Modern instruments use a single objective lens and the converging angle, needed to give a stereo view, is achieved by dividing the light path further back in the system. In practice the effect is almost indistinguishable from that obtained with two completely independent optical pathways. All stereo microscopes are fitted with erecting prisms similar to those in binoculars. This makes manipulation of the specimen easy. Stereo microscopes are often used for the dissection of small biological specimens and special long distance working stereo microscopes, on movable boom stands, are used in operating theatres for delicate surgery. Stereo microscopes are used in practically every modern industry. Many are fitted with an extra viewing tube to which a camera (film, digital or video) can be fitted. Some instruments do not even have eyepieces and a video monitor is used to view the specimen.

There are a large number of different companies making these instruments now and Leitz, Zeiss, Olympus and Nikon lead the field. Wild, famous for their Stereo Microscopes, and Bausch and Lomb who built the excellent Stereozoom, amalgamated with Leitz and some of their features were incorporated into the present line of Leitz instruments. Leica Wild stereo microscopes such as the MZ8 and the MZ16 are the best in the world. The range of Leica Stereo Microscopes available is huge and there are at least a dozen special digital cameras available to fit the M series Microscopes.

A simple Leica Wild routine Stereo Microscope.

A Stereo Microscope in the workshop.