These are low-power devices with two eyepieces that are used primarily for inspection purposes. They tend to stay in the 10-40x range to observe details in larger solid specimens like fossils, stamps, coins, or circuit boards. Unlike a Compound Microscope, the Stereo Microscope most commonly uses light from a top-mounted source to illuminate the sample or subject—as opposed to being lit from below and through the sample as with a compound microscope. Two independent, or stereo, light paths produce a true three-dimensional image when you look through the binocular head. This provides a depth to images and gives the user better resolution and perspective over a compound microscope that produces two-dimensional images due to its single-light path system.
The anatomy of the Stereo is virtually identical to the Compound, except for some key differences.
The stereo microscope will have a pair of objectives of the same power. This is in order to obtain the two independent light paths.
Because of the typical usage of this type of microscope, the images will be corrected—so moving the specimen left will move the image left, and moving it forward will move the image forward.
Most will have a built-in or attached light source on the top, since specimens will normally be solid; although some models have a lower light source. Lower-end models might not have a light source and users will have to rely on external lights for illumination.
Often the entire Nosepiece/Head optical system can be adjusted up and down for proper placement relative to the specimen, with travels up to several inches. Many models will have the stage built into the base for better specimen stability. The part that the optical system is mounted on is called the Pillar and there will be a locking mechanism to hold the optical system at the desired height.