Microscope FAQ

Compound Microscopes

  • An instrument fitted with objectives and an eyepiece lens and used for viewing small objects at high magnifications.
  • Light is passed through the specimen and it transmits the image through the objectives and into the eyepiece.
  • The image will appear upside down and reversed from left to right.

  • Place a prepared slide onto the stage using the stage clips to secure it. If the microscope has a mechanical stage, allow it to come into contact with the slide.
  • Always start with the nosepiece in the lowest powered objective.
  • Turn the focus knobs so that the stage and objective are as close together as they will go.
  • Turn the illuminator to the "on" position. Light should come from the sub-stage illuminator.
  • Look through the eyepiece and slowly turn the coarse focus knob so that the stage and objective are moving away from each other.
  • Continue until the image appears.
  • Once the image is in focus, use the fine focus (if available) to focus the image clearly.
  • After the image is in focus, switch to a higher power objective.
  • Adjust the diaphragm to either Disc or Iris to manipulate the amount of light that passes through the image. This will increase the clarity of your image.
  • 100X il Immersion Objective
    • Follow above steps until ready to switch to the 100X objective (Oil Immersion Objective)
    • Rotate the nosepiece so that the 100X objective is pointing toward the stage
    • Focus the image
    • Switch the objective out of the light path and place one drop of immersion oil unto the slide.
    • Swing the 100X objective back over the slide. The oil should form a little column from the objective to the slide with no space in between
    • When finished using the 100X objective, wipe off the oil from the objective. Do not let the oil dry. This will decrease visibility and eventually ruin your objective
    • Once the oil is placed on the slide, do not switch objectives.

Microscope Heads

  • Monocular – One ocular tube that can be a straight tube at a 90° angle or 45° inclination. Most are rotatable 360°.
  • Dual 45° head– Two ocular tubes that are both set at 45° inclinations. Allows two people to view the microscope simultaneously.
  • 90° dual head – Two ocular tubes, one at 45° and the other at 90°. Generally used for video microscopy.
  • Binocular head – Two eyepieces used for prolonged viewing.

Microscope Stages

  • Plain – A standard stage with two stage clips. Use fingers to move the slide around.
  • Mechanical Stage – Able to move slide by turning two knobs in the y-axis and x-axis.
  • Built-in Mechanical Stage – Entire stage moves when the controls are turned.

Microscope Illuminators

  • Tungsten – “Incandescent light.” Most common and cheapest. Gives off a yellowish color and gives off extra heat.
  • Fluorescent – Heat given off is very minimal and has a cool bright, white light.
  • Halogen – Found in most advanced microscopes. It's the brightest light but gives off excess heat.
  • LED – Newest lighting option. Rechargeable batteries power the LED light. Produces a very bright, white light and less heat than a fluorescent bulb.

Stereo Microscopes

  • A stereo microscope is more advanced and is frequently used for dissection and has two separate optical systems for each eye.
  • A three-dimensional image is viewed and the image is oriented the same way it actually is (not rotated or flipped).
  • The specimen is placed on the stage and it is easier to manipulate during a dissection.

  • Place the specimen on the stage plate.
  • Turn the power on if there is an illuminator. Select either incident (light shines from the top) or transmitted (light shines from below) or both simultaneously depending on the options available.
  • Focus the specimen and then take both eye tubes and gently move them towards or away from each other until a single three-dimensional image with both eyes is seen.
  • One of the eye tubes has a knurled ring. This is the diopter adjustment and is used to adjust the focus to match the eyesight.
  • Close the eye using the eye tube with the diopter adjustment and focus on one area of the specimen using the focus knobs.
  • Close the second eye and focus the specimen using the eye tube with the diopter adjustment by turning the diopter.
  • The image should be in sharp focus for both eyes.

  • Eyepieces – most come with 10X eyepieces as standard. 5X, 15X and 20X eyepieces are available.
  • Objectives – Auxiliary lenses are available for some microscopes to increase or decrease the magnification.
  • Lenses are normally 0.5X, 1.5X, and a 2X.
  • Illuminations – Dual illumination, incident (top) and transmitted (bottom).
    • Tungsten – "Incandescent light". Most common and cheapest. Gives off a yellowish color and gives off extra heat.
    • Fluorescent – Heat given off is very minimal and has a cool bright, white light.
    • Halogen – Found in most advanced microscopes. It's the brightest light but gives off excess heat.
    • LED – Newest lighting option. Rechargeable batteries power the LED light. Produces a very bright, white light and less heat than a fluorescent bulb.
  • Base styles – Standard stereo microscope comes on a post style base. Fixed body or boom stands are available.

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