What is Microscope and how it works ?

High magnification and resolution won’t guarantee that you will actually see the image of the specimen. If all of the light passes through a cell no details will be visible. Some light frequencies must be absorbed to different degrees by structures inside the cell and this allows you to see the specimen.

Using a microscope’s condenser or diaphragm, the size and intensity of the light beam can be modified. A narrow beam provides higher contrast.

overall magnification m is the product of the individual magnifications: m = mome, where mo is the magnification of the objective and me is the magnification of the eyepiece. This equation can be generalized for any combination of thin lenses and mirrors that obey the thin lens equations.

A compound microscope uses a very short focal length objective lens to form a greatly enlarged image. This image is then viewed with a short focal length eyepiece used as a simple magnifier. The image should be formed at infinity to minimize eyestrain.

In a working microscope, the length L in the sketch above is much longer than either of the lens focal lengths fo and fe.

Light from a mirror is reflected up through the specimen, or object to be viewed, into the powerful objective lens, which produces the first magnification. The image produced by the objective lens is then magnified again by the eyepiece lens, which acts as a simple magnifying glass.

It is important to know the functions of each part. Microscope Parts. Eyepiece Lens: the lens at the top of the microscope that you look through. They eyepiece is usually 10x or 15x power. Tube: Connects the eyepiece to the objective lenses.

The idea behind how an optical microscope works is to put your tiny object close to the focal point of the objective lens, but further out than the focal point. This will create an "image" of the object some distance out from the lens. This is, by the way, how a magnifying glass works.

a second lens is placed such that the image is closer to the lens than the focal point, which moves the image back but makes it appear much larger.

Start at your object and the first lens. Just use the height of the object for reference. Draw a line straight perpendicular into the lens and stop it at the lens plane. Draw a second line either to the exact center of the lens or through the left focal point of the lens, just depending on your artistic skills.

A microscope is composed of four important parts -  the light producing unit, which uses tungsten-halogen, or arc discharge. This light is collected by the condenser lens, which focuses the light onto the specimen. Presence of condensers makes the image much sharper

Sometime about the year 1590, two Dutch spectacle makers, Zaccharias Janssen and his father Hans started experimenting with these lenses. They put several lenses in a tube and made a very important discovery. ...

The objective is the first lens that light from the spcimen passes through. It is the most complex to construct, and is made to have a short focal length. The final lens is the eye piece, which further magnifies the image, and creates an image perceivable by the human eye.

The aperture of a microscope determines its resolving power. Resolution is the ability of a microscope to keep all specific details of the object intact in the image.

Microscope lenses were not used much until the end of the 13th century when spectacle makers were producing lenses to be worn as glasses.

all microscopes, based on the technique being used, have a magnification limit at which there is no longer more resolution. Simple ways to get around this is through techniques like oil immersion, which create a refractive index difference to bend the light inwards, and increase the magnification limit.

A telescope must gather large amounts of light from a dim, distant object; therefore, it needs a large objective lens to gather as much light as possible and bring it to a bright focus. Because the objective lens is large, it brings the image of the object to a focus at some distance away, which is why telescopes are much longer than microscopes.

Microscope must gather light from a tiny area of a thin, well-illuminated specimen that is close-by. So the microscope does not need a large objective lens. Instead, the objective lens of a microscope is small and spherical, which means that it has a much shorter focal length on either side.

Microscope has a light source and a condenser. The condenser is a lens system that focuses the light from the source onto a tiny, bright spot of the specimen, which is the same area that the objective lens examines.

For the purposes of understanding how microscopes function, we will "dissect" a compound light microscope into its component parts.

In a light microscope, the lowest power objective (frequently 4x or 10x) is referred to as the "scanning" objective, as it allows the observer to find an area of interest before increasing magnification