©David B. Fankhauser, Ph.D.,
Professor of Biology and Chemistry
University of Cincinnati Clermont College,
Batavia OH 45103
 Left side view of a 
binocular microscope

This page has been accessed Counter times since 11 October 2001. 
24 June 1987, latest rvsn 2Jan96, 23Sept96, 16Dec96, 7July97, 17Sept97, 30June98, 7July00, 25June01, 8July04
Right side view of a 
binocular microscope


  1. To carry a microscope: first clear your desk to recieve the microscope, then grasp its arm firmly, lift and support under the base with other hand, set on a cleared desk. Remove and store its dust cover in cabinet under desk. Unwrap power cord, loop once around gas outlet at rear of desk, plug into electrical outlet in front of desk.
  2. Clean the lenses: use ONLY lens paper. Polish the objectives and oculars: breathe on them lightly for moisture.  If the view is still foggy, ask for help.  (Slides may be polished with Kimwipes.)
  3. Always begin slide set-up with the stage lowered and the lowest power objective (4x) in place.
  4. Focus initially only by LOWERING the stage to the focal point using the coarse focus. NEVER raise the stage using the coarse focus during focusing.  (The objective may ram the slide which can damage both.)
  5. Use only the fine focus with higher power objectives. Make only minor changes in focus when necessary with the fine focus knob. If you totally lose focus, return to a lower power objective to find the focal point. Do not use the 100x objective unless you have received specific instructions on its use. (See a separate handout for oil immersion procedure.)
  6. Carefully follow microscope use instructions. (See Using and Evaluating the Microscope .)
  1. Get out the microscope, using proper carrying technique (see rule 1 above), place on a cleared desk.
  2. Note how the cord is neatly wrapped around the base (we hope): not twisted or bent back, snugly wrapped around the lamp housing and arm, with the plug is securely tucked in under the cord. Always rewind the cord in this configuration.
  3. Draw a right side view of the microscope (oculars point to L), label or explain all of the following. Briefly note various functions. (You may be tested on any of these...):
Here are labeled views of the features of the microscope you should be familiar with:
labeled RIGHT side view of a microscope
labeled LEFT side of a microscope

light path 
power switch
lamp and housing
lamp rheostat
iris diaphragm & lever (Here is how it works.)
condenser positioning knob
mechanical stage, retaining screws
mech stage positioning knobs
slide retainer and thumb knob
coarse focus (show dir to lower) 
fine focus
parfocal objective lenses (when one objective is in 
                        focus, all should be close to in focus) 
achromatic coating (prevents "rainbow edges.")
nosepiece or turret
optical head 
optical head retaining screw 
binocular focus ( L adjustable ocular
interpupillary distance

Here is a view of the left side view of the microscope .


lamp rheostat Use the rheostat setting at as low a setting which produces adequate lighting (around 5-7). Too high a setting generates excessive heat and reduces the life of the $50 bulb.
 iris diaphragm lever Move side to side while viewing through the ocular. What happens? Here is an excellent animation of the action of the iris diaphragm in adjusting the aperature and the rheostat.

Here are the stages of adjusting the iris diaphragm. 
Note the position of the lever and the resulting aperature: 

Coarse and Fine focus Which direction do you rotate the coarse focus knob to lower the stage? Memorize this direction. Use coarse focus only with the 4x objective.

Note: the fine focus moves the stage almost imperceptibly

Nosepiece (turret) With the stage lowered, rotate the nose piece so that each of the objectives is successively pointing down, clicking when the objective is in proper position
Ocular What is the magnifying power of the ocular? What would the power of magnification be if you were using the 4x objective with this ocular?

Note that the left ocular is adjustable.  Begin with it set on zero, and adjust if necessary so that the image is focused for both eyes.

Here is an excellent site which covers the history of the microscope.