1. The Microscope

3. The Basics
A microscope is an optical instrument that uses a lens of a combination of lenses to magnify and resolve the fine details of an object
The earliest microscope is a single lens microscope: the magnifying glass
The larger image you see when looking through a microscope is called a virtual image

4. The Basics
You place an object under the lower of two lenses, called the objective lens, it is viewed through the eyepiece lens

5. The Basics
The following are the types of microscopes used by forensic scientists
Compound microscopes
Comparison microscope
Stereoscopic microscope
Polarizing microscope
Microspectophotometer
Scanning electron microscope (SEM)

6. The Compound Microscope
Base- ALWAYS CARRY WITH ONE HAND ON BASE
Arm- supports the microscope, ALWAYS CARRY WITH ONE HAND ON ARM
Stage- place you put specimen on, generally on a glass slide and placed under the clips
Body tube- where the objective and eyepiece lens is
Coarse adjustment- raises and lowers the stage, DO NOT use if you are on a high magnification

7. The Compound Microscope
Illuminator- transmitted illumination when light passes up from the condenser and through the specimen.
Condenser- lens system under the microscope stage to collect light and focus them on the specimen
Objective lens- the lenses for magnification
Eyepiece or ocular lens- lens closest to eye, can be monocular or binocular

8. The Compound Microscope
Always focus your specimen on
the lowest magnification first
When you increase a compound microscope’s magnification, its field of view and depth of focus decrease
Field of view- area of a specimen seen
Depth of focus- the thickness of a specimen that is entirely in focus under the microscope

9. The Comparison Microscope
Two compound microscopes in one unit
Very useful for looking at two different things for comparison
When you look into the comparison microscope you see both specimens at the same time
Modern firearms examination began with the first comparison microscopes

10. The Stereoscopic Microscope
Two monocular compound microscopes properly spaced and aligned to present a 3-D image of a specimen to the viewer
Ideal for microscopic examination of big, bulky items