Best Answer: A low power objective is essential on any microscope, It allows you to quickly scan a large area of the specimen, and to locate those areas which need closer study with a high power objective. For example, a histologic section of liver might measure 20 by 40 mm. With a 4x objective you can scan the entire piece of tissue in a minute or less. If there is a 1 mm tumor somewhere in the section, you will find it during this scan, and can them zoom in on it with the high power objectives. Trying to scan the entire slide with a 40x objective would take a long time because in any given field you can see only 1/100 the surface area included in a 4x scan), and you could easily miss a 1 mm tumor entirely. The usual lab microscope contains,ocular lens which magnify 10 times,and low power objective add another 10 magnification so the magnification becomes 10 x 10=100. Also, there is the scanning objective, which is smaller than the low-power objective.You can look at a large area and find a small item in it that you might want to take a closer look at. You then switch to higher power objectives to “zoom” in on the details of that section making them 10 or 100 times bigger in your eye’s view.
If you start out at a high power objective, then you will only see a physically small space and would never find the point of interest.Remember: low power, large area of view. High power, small area of view! The lowest magnification power is x4 (Eyepiece Lens) times x10 (Objective Lens) = x40 Magnification. The low power objective is useful for allowing you to focus your lens on the object that you wish to study without too much difficulty. Then it should be possible to simply switch to a higher power objective lens without having to do more than make a small adjustment to the fine focus knob. Another advantage of the lower power lenses is to allow scanning for something that may be of interest, without needing to examine each field in minute detail when the organism/organelle of interest is not present. When you see something of potential interest, you can then switch to a higher power lens.
The standard laboratory microscope is outfitted with an ocular lens that provides a magnification power of 10x. The total magnification power can be found by multiplying the ocular magnification by the magnification of the selected objective. This means that the total magnification of the ocular lens and the low-power objective would be 10 x 10 = 100x. A smaller objective than the low-power objective is known as a scanning objective.Assuming nothing a 45x objective will magnify the image 45 times multiplied by the magnification of the eyepiece multiplied by the actual tube length of the microscope being used divided by the tube length the objective was designed for. In the case of an infinity objective it is multiplied by the distance the eyepiece is from the tube lens divided by the diastase the microscope was designed to have instead of the difference in tube lengths. In almost but not all cases this value will be
1. However if you need accurate results you must calibrate the eyepiece end objective on the microscope you use. Gordon,The low-power objective on a microscope is the shortest or second shortest objective lens found on standard laboratory microscopes. Low-power objective lenses typically add 10x to the magnifying power of the microscope.
