Optical microscope, or light, is the most common type of microscope.
It can be SIMPLE, meaning that it’s consisted of a single lens, and it can be COMPOUND, consisting of several optical components in line.
The most important differentiating factors are the number of lenses on each of these two microscopes and the level of magnification.
A simple microscope has one biconvex lens, often with a short focal length.
A simple microscope is used to produce an enlarged image of an object placed within its focal length. In simple microscope there is single lens, whereas in compound light microscope there are 3 to 5 objective lenses, which means compound light microscope has better magnifying power.
That’s why compound light microscope has wide range of use in studying and observing, and it’s used by professionals for research purposes.
Single-lensed simple microscope has the magnification power up to 300×, and can resolve below 1 micrometre, whereas compound light microscopes can magnify up to 2,000×, and can resolve down to about 0.2 μm.
A simple microscope has one level of magnification and its magnification is not adjustable and the compound microscope has a much higher level of magnification and is adjustable.
The magnification power of compound light microscope comes from his structure of two systems of lenses. One is the ocular, or eyepiece lens that one looks into and the objective lens, or the lens that are closest to the object.
The objective lens creates a resolved image that is then magnified by the eyepiece lens for viewing. It also has different zoom levels of magnification.
Another distinction is the use of the light. Simple microscope use natural light source, and compound microscope use illuminator.
Illuminator is another advantage of the compound light microscope because with that light very small pieces can be seen. The intensity of lights for object magnification is adjusting with the help of condenser lens, known as one of the main components of the optical system of many transmitted light compound microscopes. Because simple microscope use only natural light does not contain condenser lens.
Simple microscope use mirror that is concave-reflecting type, and compound light microscope use mirror that is plane at one side and concave at other side. At compound microscope this mirror is located beneath the stage and with its concave and plane surfaces gather and direct light in order to illuminate the object.
Difference between simple and compound microscope
|Simple Microscope||Compound Microscope|
|Number of Lenses||Single||3 to 5 objective lenses|
|Magnification Power||up to 300×||magnify up to 2,000×|
|Can Resolve Below||1 micrometre||0.2 μm|
|Level of Magnification||One||Higher Level|
|Adjustable Magnification||Not Adjustable||Is Adjustable|
|Light Source||Natural Light Sourc||Illuminator|
|Mirror||Concave-Reflecting Type||Plane at one side and Concave at other side|
|Usage||Not used often||Everywhere from research labs to high school biology classrooms.|
Other adjusting differences
Use of knobs on compound light microscope is very common, because it helps on focusing that gives clear image to be seen. Simple microscope does not use hooks and knobs that much. Also, simple microscope stand is small with hollow cylindrical attached to the base and is used to hold the microscope. Compound light microscope arm is curved and is used to hold the microscope. Simple microscope has one adjustment screw that is used to move the limb up and down for focusing, and compound light microscope has coarse adjustment screw for rapid focusing an object and fine adjustment screw for fine and sharp focusing.
Anthony Leeuwenhoek, known as the father of microscopy, with the simple microscope discovered:
- microorganisms – bacteria,
- blood cells
- and many tiny animals swimming in a drop of water
so, in that way founding the science of microbiology.
Nowadays, simple microscopes are not used often because the introduction of a second lens led to the more powerful compound microscope.
Today, compound light microscope is used everywhere from research labs to high school biology classrooms.