To further understand the features and usage of a stereo boom microscope, we will try to look at and understand the concept behind stereo microscopy—the science that explains how images are formed within the instrument and how it is projected and magnified. Human functions are basically controlled by the brain; our senses are produced by the translations of the information that our organs sends to the brain. Thus, the human eyes and the brain functioning together is responsible for the colors, form, dimensions and other physical features of the objects that we see—leading us to the so-called “stereoscopic vision”. We have two eyes, each having its own projection of an image that we are looking at. Being separated by an average distance of 64-65 millimeters away from each other, it is a given that each eye should be looking at an object at slightly different view points, explaining why we see objects in three dimensions (3D). This phenomenon is due to the brains interpretation of the images that are received from each of our retinas; the images are slightly different considering the factors such as angle and distance. These two images, when transmitted to the brain, fuse together and forms a single image with a remarkable amount of depth—three-dimensional perception.

A stereo-type microscope takes advantage of this ability of the brain to perceive depth by transmitting two separate images of a specimen that are slightly inclined at varying angles, commonly between 10-12 degrees is the widespread setting for most manufacturers. Two separate oculars or eyepieces (binocular-type) are commonly present to produce that imaging effect. There are two types of systems used in producing a true stereoscopic projection, both having positive and negative characteristics. The older stereomicroscopic system utilizes two separate but identical and symetrical optical systems inclined together with the objectives zeroed in on a single point at different angles. Each optical system has its own objective and ocular lenses accurately arranged and aligned inside a single body housing. The major advantage of this design type is the degree of numerical apertures that can be attained. This is mainly because the objectives are very similar to the designs utilized by classical compound microscopes. The newer system utilizes the use of a single large objective that is shared by two separate optical systems. This system has the practical advantage over the older system by allowing the ease of introduction of accessories. Having a single main objective, it produces a parallel bundle of light rays between the lens systems; thus, introduction of added accessories do not introduce significant amount of aberrations of shifts in the position of the images.

It is difficult though to determine whether which of the two systems are more superior than the other. This is mainly because there is no universally accepted criteria for the comparison of performance between stereomicroscope systems. The main decision is then based on the appropriateness of the instrument with regards to the task that is at hand.