Brightfield Microscopy continued
TERM EXPLANATION
Magnification, total
Numerical aperture (NA)
Objectives
Ocular
Parcentric
Parfocal
Planachromatic objective
Resolution
Rheostat
Tungsten-halogen bulb
Virtual image
Working distance
Magnification of ocular × magnification of objective. 1,000× is highest magnification achievable with
brightfield microscope.
Mathematical expression of light admitted by lens. The higher the NA, the greater the resolution.
Lenses attached to revolving nosepiece. Most commonly used are low power (10×), high power (40×), &
oil immersion (50× or 100×).
Eye piece. Usually 10×.
Object in center of field at 1 magnification will be in center of field at other magnifications
Object remains in focus from 1 magnification to another
More expensive objective that corrects for curvature of field. Results in flat field with uniform focus.
Ability to reveal fine detail & distinguish between 2 close points.
Light control knob. Light intensity shouldn’t be regulated by condenser or diaphragms.
Type of bulb used for brightfield microscopy.
Image seen through microscope. Upside down & reversed.
Distance between slide & objective. Decreases with higher magnification objectives.
Laboratory Operations Review 38
