How Does a Stereo Microscope Differ From a Compound?

Optical Components

• Both types possess identical structural elements: the head/body, which contains the optical units; the arm, which conjoins the head and the base, providing a means to transport the device; the base, which holds the illuminator and the whole apparatus.

  Stereo, dissecting or binocular microscopes always have two identical magnification eyepieces, or ocular components, through which specimens are examined. Their set-up is similar to two compound microscopes working independently, while alongside each other.

  The interchangeable primary lenses or objectives allow requirement-dependent magnification level adjustments and can come as fixed separate single objectives; a zoom; or in rotating turrets fitted with multiple lenses. This enables independent optical paths to the subject, which can be viewed at two different angles.

  Compound microscopes can come either in single or double eyepieces; working with three to five lenses. The objective lenses may be rear or forward facing. A third lens, the oil immersion objective, allows closer examination of specimens while immersed in oil.

  Compound microscopes follow a single optical path system for magnification and provide a single vertical view from atop the specimen. Some models have a third tube for mounting a camera.

Focus Knobs

• Stereo microscopes are normally built with a single focus knob. Using rack-and pinion principles, this part moves the head up or down, to bring the specimen into view.

  Compound microscopes have two coaxial focus knobs for either coarse or fine focus adjustment. The coaxial configuration permits adjustments without needing another knob.

Magnification

• Greenough stereo microscopes provide low magnification power, despite the fact that they provide 3D viewing capabilities. They are relatively more inexpensive than the parallel types, which provide broader amplification and allow accessory interlock between the eyepiece and the objective. Image projection is laterally upright.

  Compound microscopes, using several objective lenses mounted on a turret compounded by ocular eyepieces, allow high-grade magnifications from 4x to 100x. The image provided is backward and upside down -- and it is two-dimensional.

Applications

• Stereo microscopes are commonly used in biology, document examination, gemology, hair grafting, metallurgy, dentistry, engraving and collection, geology, embryological studies and electronics.

  Compound microscopes are primarily used in biology, ferrography (particle wear analysis), clinical laboratories and educational institutions and specialized medical fields such as oncology and veterinary medicine.