October 2026 - Microscopy Study Guide

Core ideas to know

Learn the relationships, not a string of isolated definitions. These are the facts that let you reason through unfamiliar wording.

• Total magnification equals eyepiece magnification multiplied by objective magnification.
• Resolution is the ability to distinguish two nearby points as separate; enlargement without resolution adds no real detail.
• Begin with the lowest-power objective because it gives the widest field of view and greatest working distance.
• Use coarse focus at low power and fine focus at higher power to reduce the chance of striking the slide.
• As objective magnification increases, field of view and depth of field decrease, while the specimen appears larger.

A reliable way to answer

Use the same short process every time so the wording of the question does not decide your method for you.

1. Secure and centre the slide with the lowest-power objective selected.
2. Use coarse focus to locate the specimen, then sharpen with fine focus and adjust illumination.
3. Re-centre the feature before rotating to a higher-power objective.
4. At higher power use fine focus only, and calculate magnification from both lens values.

Distinctions that earn marks

Terms to know

Field of view

The circular area visible through the microscope at one setting.

Working distance

Space between the objective lens and specimen when focused.

Resolution

Ability to distinguish close points as separate details.

Key points

• Multiply ocular and objective powers for total magnification.
• Always find and centre the specimen on low power first.
• Higher magnification narrows field of view and working distance.