Compound optical microscopes are also known as compound microscopes, light microscopes or optical microscopes and come in several varieties. These include digital, inverted, stereo, monocular and binocular. All work on the same principles and deliver an enlarged image to the viewer. They have some differences though, which will be detailed here.
These are probably the ones you think of when microscopes come to mind. Using a single light as a sample illuminator and compound lenses for magnification, these have a single eyepiece. This is a bit uncomfortable, as you need to close one eye to get a clear image of what you are looking at on the slide. The eyepiece has a power of about 10X and the objectives or lenses on the nosepiece range from 2X to 50X depending on your particular microscope. The big one here is the single eyepiece.
Binocular microscopes are becoming more common. You can tell a binocular style microscope by the dual eyepiece. Simply put, you use both eyes to view the sample image. This makes them more comfortable to use and thereby more popular. Dual eyepiece scopes are used widely in high school and college classrooms. Binocular microscopes have all the same characteristics as the monocular ones above.
Stereo microscopes bring a whole new dimension to the image, literally. Whereas the typical light microscope produces a two-dimensional image, the stereo microscope uses two light sources working independently to produce a three-dimensional image to the viewer. The sample on the slide will have height, depth and width. Using all of the same features and characteristics of the other optical microscopes, stereo microscopes stand out among their counterparts.
This is where things go differently in the realms of microscopy. Standard optical microscopes use light to illuminate and lenses to magnify something that you could not see with the unaided eye.
Digital microscopes are a breed apart. This type of microscope inverts the light source, placing it above the sample. Standard optical microscopes place the light below the sample. You also get the 3D image like in stereo scopes. The difference is that the image is digitized and transmitted to a monitor or screen for viewing. Imagine watching cells divide on a 19″ monitor. The user can take still photos or moving video of the sample in real time. I think you can see the advantages here.
Inverted microscopes are used to study samples that are gravity sensitive, like gases suspended in a liquid. The inversion refers to the light source, which is typically below the sample slide. With the inverted microscope, the light source is above the sample slide. This paved the way for new innovations in digital imaging that came along.
All these different types will work for you. It’s just a matter of what you want to accomplish or study. I can tell you this, though; using any microscope will open your eyes to a whole new perspective of where we came from and what we are made of.