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Fine focusing knob

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The fine focusing knob is a part of the microscope used to make small adjustments to the focus, enhancing the clarity and detail of the specimen being viewed. It is typically employed after the coarse focusing knob has brought the specimen into general focus.

5 Must Know Facts For Your Next Test

  1. The fine focusing knob is essential for achieving sharp, high-resolution images under higher magnification.
  2. It only moves the stage or objective lenses by a very small amount, allowing for precise control.
  3. Fine focusing knobs are particularly important when using high-power objective lenses (40x and above).
  4. Using the fine focus knob can help avoid damaging slides or objectives, which can occur if only the coarse focus is used.
  5. In compound microscopes, both coarse and fine focusing knobs are usually found on the same side of the microscope.

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