Stereomicroscopes, dissection microscopes are optical microscopes that use light illumination and low magnification, allowing inspection or dissection of small microorganism or other small objects. Light is reflected off the surface of the object being viewed, rather than passing through it. There are two objectives and two eyepieces, which provide slightly different viewing angles each eye. This gives three-dimensional visualisation of the object. Stereomicroscopes are often used for microsurgery. Some stereomicroscopes have video dual CCD camera pickups attached that display the images onto a high-resolution LCD monitor. Special software can convert the two images into an integrated three-dimensional image that viewers can see, if they wear special glasses.
Light microscopes are also called optical microscopes. Compound microscopes have an objective lens close to the object being viewed, which focuses a real image of the object inside the microscope. That image is then magnified by a second lens, which produces an inverted virtual image of the object. Some compound microscopes have a special objective lens, called an oil immersion lens. To use this, a drop of Canada balsam oil, which has a refractive index very close to that of glass, is placed on the stained specimen and the objective lens is positioned so that it is in the oil. This gives a greater resolution and higher magnification. You may be able to use oil immersion objectives to view stained specimens of bacteria that you prepare. The wavelength of visible light is 400-700nm. This is too large to pass between some of the smallest organelles within cells, so they cannot be seen. However, optical microscopes do have several benefits, including that they are inexpensive, easy to use, portable and can be used in the field and able to be used to examine living specimens as well as stained sections. A photograph of a specimen seen under a light microscope is called a photomicrograph.