- Always start on low power with a clean slide. The stage of the microscopes should be down as low as possible.
- Centre the slide so the specimen is underneath the objective lens.
- Use the Coarse adjustment knob to obtain a general focus. You will be slowly raising the stage until a focus is achieved.
- Use the fine adjustment knob to obtain a clear focus.
- Centre the specimen in the low power field of view before you move to medium power.
- Without any further adjustments, switch the objective lens to medium then focus using the fine adjustment. If you cannot see the specimen at this point, go back to low power and re-centre and refocus it.
- Once you have it focused and centred on medium power, you can progress to high power.
Microscope Calculation Summary
Total Magnification
-how much the image is magnified in the microscope
-calculated for each objective power
Total magnification = ocular magnification x objective magnification
Field Diameter or Field of View
-the width of the bright circle you see
-for low power use a measurement slide and count the number of spaces you see
-for medium and high power, use the following formula:
Med. = (low power FV x low power magnification)/ medium power magnification
High = (low power FV x low power magnification)/ high power magnification
-the actual size of the specimen
Specimen Size = field of view/# of specimens that
would fit across the FV
Drawing Magnification
-how much larger than the actual object is your drawing?
Drawing magnification = drawing size / specimen size
