Answer to Question #291923 in Microbiology for Sam

Question

You need to identify structures within a cell using a microscope. However, the image appears very blurry even

though you have a high magnification. What are some things that you could try to improve the resolution of the

image? Describe the most basic factors that affect resolution when you first put the slide onto the stage; then considermore specific factors that could affect resolution for 40⨯ and 100⨯ lenses.

Answer 1

Resolution is the ability of a microscope to distinguish different features of an image. Incase of a blurred image, the following things can be done to try and improve the resolution of the image;

1.Adjust the objective lenses by rotating the nose piece so that the objective lens is rightly positioned over the slide.

2.Align the microscope optical system correctly; match the condenser to the objective with respect to numerical aperture.

3.Use shorter wavelengths of light to view the specimen. Shorter wavelengths have high resolving capability than the longer ones

4.Clean the objective lenses with cotton sparkled with 70% ethanol or use lens paper to wipe.

5.Use of correct cover glass with the given objective can help improve resolution. Adjusting the objective to the actual cover glass thickness in use is useful in improving the resolution.

        Basic factors that affect resolution

A). Objective Numerical Aperture

Resolution is directly linked to numerical aperture,that is ,the higher the numerical aperture, the better the resolution.

B).Wavelength of light used to image a specimen.

Shorter wavelength lights are capable of resolving greater detail as compared to longer wavelengths. Example, Near-ultraviolet light is known to have the shortest usable wavelength thus making it excellent in offering greatest resolution.

C).Refractive Index between objective lens and the specimen.

This simply refers to a ratio expression of relative speed of light passing through a substance as a proportion of speed of light in a vacuum. With increased refractive index, the speed of light passing through is reduced and consequently the wavelength gets shorter and better resolution is yielded.

Factors that could affect resolution for 40 and 100 lenses

1 .Poor quality lenses. These lenses are associated with blurred or else not clear images 

2 .Chromatic aberration-it is as a result of spherical lens which tend to bring different wavelengths of light into focus at different levels. This in turn causes multiple images which overlay on top of each other thereby decreasing resolution.

3 .Spherical aberration-in this case, the center of the lens has slightly different qualities than the edges thereby leading to lessened quality of the image.