What is the difference between ocular and objective magnification

JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website. Read more here This entry was posted on March 16, by Accu-Scope. Most compound microscopes come with interchangeable lenses known as objective lenses. Objective lenses come in various magnification powers, with the most common being 4x, 10x, 40x, and x, also known as scanning, low power, high power, and typically oil immersion objectives, respectively.

A scanning objective lens provides the lowest magnification power of all objective lenses. Some objectives with even lower power are discussed in Specialty Objectives below. The low power objective lens has more magnification power than the scanning objective lens, and it is one of the most helpful lenses when it comes to observing and analyzing glass slide samples. While we want light to refract differently between the specimen and the medium, we do not want to lose any light rays, as this would decrease the resolution of the image.

By placing immersion oil between the glass slide and the oil immersion lens X , the light rays at the highest magnification can be retained. Immersion oil has the same refractive index as glass so the oil becomes part of the optics of the microscope.

Without the oil the light rays are refracted as they enter the air between the slide and the lens and the objective lens would have to be increased in diameter in order to capture them. Using oil has the same effect as increasing the objective diameter therefore improving the resolving power of the lens.

This may be sufficient to view your chosen organism. Try to note how it moves and do your best to draw it as you see it, unless you need more magnification. Once you have centered and focused the image, switch to high power 40x and refocus. Note movements and draw the organism as you see it.

If you bump your microscope and lose focus, what do you do to refocus your specimen? Introduction: A microscope is an instrument that magnifies an object so that it may be seen by the observer. Parts of the Microscope:. General Procedures: 1. Make sure all backpacks, purses, etc. Carry the microscope by the base and arm with both hands. Focusing Specimens: 1.

If the specimen is too light or too dark, try adjusting the diaphragm. Cleanup: 1. Wrap cords around the microscope. Replace slides to original slide tray. Troubleshooting: Occasionally you may have trouble with working your microscope. Image is too dark!

Adjust the diaphragm, make sure your light is on. Your lens are dirty. Use lens paper, and only lens paper to carefully clean the objective and ocular lens. Phase contrast microscopy - takes advantage of phase differences in the light beam that are caused by different refractive indexes of components within a tissue.

Light travels fastest through air and slowest through glass. Thus, if a light beam encounters at the same time three different spaces of equal thickness that are filled with air, water and glass, the beam will emerge first from the air filled space and last from the glass filled space.

The emerging light beams are said to be out of phase with each other. In the phase contrast microscope, the condenser and objectives are specially made to detect the phase differences of light passing through different components within a tissue specimen. The construction of the condenser and objective lenses is such that these phase differences are made visible by increasing the contrast between light waves of different phase.

As a result, components of cells that are normally of low contrast clear or nearly clear , are given higher contrast and, thus, made visible. Polarizing microscopy - A polarizing filter called the polarizer is placed below the condenser and allows only light vibrating in one plane to reach the condenser.

A second polarizing filter called the analyzer is placed between the objective and ocular. If these two filters are oriented such that their axes of light transmission are perpendicular, no light will pass through the analyser to the ocular. So nothing will be seen. One use of polarizing light microscopy is related to the fact that certain crystals found in or associated with some cells can bend light waves because of their refractive index.

If some of the light waves that have passed through the polarizer are bent into different planes as they pass through crystalline parts of the specimen, then some of these light waves will be able to pass through the analyser even if it is oriented at 90 degrees to the polarizer.

This property of crystals to bend polarized light waves is called birefringency. It is important in identifying certain crystalline structures in or associated with cells. Interference or Nemarski interference microscopy. It is not the same as phase contrast microscopy. Nemarski interference microscopy requires 2 different light beams that are recombined after passing through the specimen. Differences in phase between the two beams are visualized as depth. The result is an image with depth sort of 3-D.