Light Microscopy Basics

Light Microscope

• Microscopes are used to magnify objects too small to be seen by the naked eye.
• Microscopy is a technical field that uses microscopes and objectives to view samples in detail.
• A microscope is a precision instrument with lenses that magnify images of small objects.
• It uses a light source to make the object easier to see.

Microscopy

• Microscopes are used to get a magnified image to see structures that cannot be seen with the unaided eye.
• Magnification is the ratio of the size of an object seen under a microscope to its actual size.
• Total magnification is calculated by multiplying the magnifying power of the objective lens with the eyepiece.

Types of Light Microscopes

• Microscopes use a light source to illuminate the sample.

Objective Lenses

• Objective lenses are the lenses closest to the specimen.
• They are essential for magnification.
• Most compound microscopes have 4x, 10x, 40x, and 100x objectives.
• They are mounted on a revolving nosepiece to change magnification.
• Total magnification = Ocular lens x Objective lens.

Ocular Lens (Eyepiece)

• The eyepiece magnifies the image projected by the objective lens.
• They are typically 10x, with others available as well.
• The "x" refers to the magnification power of the lens.
• The eyepoint is the distance from the eyepiece for optimal viewing.

Other Parts

• Diopter adjustment: Used to adjust focus on one eyepiece for vision correction.
• Body tube (Head): Connects the eyepiece to the objective lenses.
• Arm: Connects the body tube to the base.
• Coarse adjustment: Brings the specimen into general focus.
• Fine adjustment: Fine-tunes the focus and increases detail.
• Nosepiece: Rotating turret that houses the objective lenses.
• Specimen or slide: The object being examined, usually mounted on a flat glass slide.
• Stage: Flat platform where the slide is placed.
• Stage clips: Hold the slide in place.
• Stage height adjustment: These knobs move the stage left/right or up/down.
• Aperture: Hole in the stage that allows light to reach the specimen.
• On/off switch: Turns the illuminator on or off.
• Illumination: Light source used to illuminate the specimen.
• Condenser: Gathers and focuses light from the illuminator onto the specimen.
• Base: Supports the microscope and houses the illuminator.