Field Notes Journal a personal natural history of place

0.3 Comparison of Magnifying Powers

Aim

To compare field size and visible detail at different magnifications.

Specimen & Apparatus

• Stage micrometer slide
• Prepared slide (any specimen)
• Compound microscope with multiple objectives

Method

1. Focus the stage micrometer under low power.
2. Observe the number of divisions visible across the field.
3. Change to a higher power objective and refocus.
4. Compare the visible field size and clarity of the scale.
5. Repeat the process using a prepared specimen.

Observations to Make

• Change in field diameter with increasing magnification.
• Increase in visible detail at higher powers.
• Reduction in depth of field.
• Any change in brightness or ease of focusing.