Microbiology And Microsocopy: The History Of Microscopes

Introduction.
Microsocopy has been of prime importance in various fields in biology studies like microbiology, zoology, botany, biotechnology and various other feilds, owes it's existence to Antony Van Leeuwenhoek. In 1673 early microscope consisted of a bio cancave lens and in two metal plates. Over the years, microscopes have evolved from the simple, single-lens instrument of Leeuwenhoek, with a magnification of 300, to the present-day electron microscopes capable of magnifications greater than 250,000. The two important types of microscopes are light microscope and electron microscope.The former use visible light or ultraviolet rays to illuminate specimens. The different types of microscopy includes bright feild microscopy, dark feild, phase contrast and fluorescent microscopy. Fluorescent microscope use UV radiation whose wave length are shorter than those of visible light. Electron beams are used in electron microscope and also magnets.
Features of various microscope.
Bright feild microscope.
Brightfeild microscopes have two lens system for magnification of specimen. The two lenses are ocular lens at

It provides a shelter for the lens system and the ocluar and the eye piece are located at the other end.

Basic theoretical principles of microscopy.
To make the best out of a microscope it is important to know the basic principles of microscopy. They are : Magnification, resolution, numerical aperture, illumination and focusing.

Magnification
This function is performed by the two lens system; the ocluar lens at the eye piece and the objective lens at the nose piece. The body tube separates the two lenses. The specimen is magnified by the objective lens. A real image is produced and can be seen at the focal plane. Ocluar lens magnifies that images and projects it as final image. Many microscopes have revolving nose piece with different degrees of magnification.