Magnification
how much larger the image appears
Resolution
ability to distinguish two close objects
Resolving power
microscope’s ability to produce detail
Limit of resolution
smallest distance between two objects still seen separately
Parfocal
image stays focused when switching objectives
Aperture
opening that lets light through
Magnification
Ocular lens = 10x
total magnification formula
Total magnification =
ocular × objective
Example
10x ocular × 100x objective = 1000x
4 Types of Microscopy
Brightfield
Darkfield
Phase contrast
Fluorescence
Brightfield
dark cells on light background
Darkfield
bright cells on dark background
Phase contrast
internal structures visible
Fluorescence
glowing cells with fluorescent dyes
Focusing a Microscope
Start 4x objective
Use coarse knob
Center specimen
Switch to 10x
Use fine knob
Switch to 40x
Adjust light/diaphragm
Add immersion oil
Switch to 100x
Use fine focus only
Cleaning lenses
Use lens paper only (never tissue).
