Abbe Condenser: This is a system of different lens elements which is mounted beneath the stage. It contains an iris diaphragm which controls the diameter of the light beam. The light beam should be adjusted to be larger or equal to the numerical aperture of the objective in use. Condensers can be moved up and down. The normal operating position is up.
Achromatic lenses: These lenses are designed to correct chromatic abberation for two colors (in contrast to apochromatic systems). Acrhromatic lenses are cheaper and popular in education.
Apochromatic lenses: These lenses are designed to correct chromatic aberration of three colors. They are more expensive and suitable for photographic work.
Arm: The arm connects the base of the microscope to the tube holding the eye piece (ocular).
Base: The bottom part of the microscope – it contains the lamp.
Binocular Head: The top part of a microscope designed to carry two eye pieces.In compound microscopes a binocular head does not give stereoscopic vision (3D).
C-mount: This is an adapter format to connect video cameras to the microscope.
Coarse Focus: Also referred to as rough focus, this knob raises and lowers the stage quickly. It should only be used in connection with the low magnification lenses.
Condenser Lens: This is a lens system which is mounted beneath the stage. It concentrates the light from the lamp so that the image of high power objectives is sufficiently bright. It is also necessary to increase resolution.
Cover Slip: This is a square piece of glass holding the specimen in place. The thickness of the cover slip influences the resolution of the image. Many objectives are manufactured for a cover slip thickness of 0.17mm.
Diaphragm: This is used to control the amount of light entering the objective. The diaphragm is a part of the condenser. By controlling the diameter, resolution and contrast (as well as the amount of light entering the objective) can be controlled. The effect of the diaphragm becomes more apparent at higher magnifications.
DIN Optics: This is a German standard of microscope optics. Objectives that are manufactured according to the DIN standard are interchangeable. The tube length is standardized to 160mm and the threads are standardized as well.
Diopter Adjustment: In binocular microscopes, the diopter adjustment is useful to compensate visual differences of the two eyes. This way it is possible to use the microscope without wearing glasses.
Eyepiece Lens: Also known as ocular lenses, they magnify the image of the objective. The eyepiece is the lens into which a person looks into when observing. The total magnification of a microscope is calculated by multiplying the magnification of the objective by the magnification of the eyepiece. Many eyepiece lenses have a magnification of 10x ot 15x.
Fine Focus: This focus knob moves the stage up and down in small steps. It is used to focus at different layers of the specimens.
Field of View: This is the diameter of the image that you see when looking into a microscope. The larger the field of view (FOV), the more of the specimen is visible. The FOV changes with magnification. The higher the magnification, the lower the FOV.
Focus: This refers to the changing of the distace between objective to specimen to obtain a crisp picture. In most cases the stage is raised or lowered with the coarse and the fine focus knob.
Head: This is the top part of the microscope. It carries the eyepiece(s) and other optical elements. There are several different types of heads: a monocular head is designed to carry only one eyepiece, a binocular head carries two (but does not give stereoscopic vision in compound microscopes) and a trinocular head is designed to carry a camera as well.
Illuminator: This is the light source of the microscope.
Immersion Oil: This is an oil which is used only with oil immersion objectives. A drop of oil is placed on the specimen and the objective is rotated directly into the oil. This way the resolution of the image is increased.
Interpupiliary Adjustment: It is possible to adjust the distance of the eyepieces of stereo or binocular microscopes. If a child only looks through a binocular microscope with one eye only, then this may be an indication that the distance is set to a too large distance.
LED Light Emitting Diodes These can be found instead of a lamp in some microscopes. They consume very little energy and are a cold light source. They do not heat the specimen.
Mechanical Stage: This type of stage is equipped with a slide holder and two knobs to turn. One knob moves the stage backwards and forwards, the other one moves the slide sideways.
Mirror: A mirror is an alternative to an electrical lamp. Mirrors are often used in field microscopes. It is important that the mirror is not directed towards the sun. This will result in overheating of the specimen and in eye damage.
Mechanical Stage: This type of stage is equipped with a slide holder and two knobs to turn. One knob moves the stage backwards and forwards, the other one moves the slide sideways.
Mirror: A mirror is an alternative to an electrical lamp. Mirrors are often used in field microscopes. It is important that the mirror is not directed towards the sun. This will result in overheating of the specimen and in eye damage.
Monocular Head: This is a microscope head is able to carry only one eyepeice (in comparison to a binocular head, which carries two).
Nosepiece (or revolving nosepiece, turret): This part carries the objectives. It can be rotated.
Numerical Aperture (N.A.): This number is imprinted on the objective lens. It is a measure of the resolving power of the objective (how fine a detail can be seen). The condenser aperture diaphragm should be adjusted to the same value of the N.A. of the objective, to obtain the best results.
Objective Lens: This is a highly magnifying lens system, it is located close to the specimen to be observed. The image of the objective is then magnified again by the ocular lens which is close to the eye.
Oil Immersion Lens / Objective: This is a specially designed objective lens (usually with a 100x magnification) which is used together with immersion oil. The objective is rotated into the immersion oil, with the consequence that the image is of a higher resolution and brightness. Oil immersion objectives have the word “OIL” written on it.
Parfocal: Parfocal objectives belong to one series. It is possible to change the magnification without requiring a refocusing. Parfocal systems are highly recommended for educational purposes.
Pointer: This is an arrow which can be seen when looking through some eye pieces.
Rack Stop: This is a safety measure which prevents you from turning the focus knob too far and from crashing the objective into the slide. You can adjust the rack stop if you need to get closer to the objective.
Resolution: This is the ability of the microscope to show two points as distinct objects. It is the distance at which two points can still be seen as separate points. The higher the resolution, the finer are the details which can be seen.
Reticle: This is a grid which can be seen through some eyepieces. It allows you to make size measurements.
Ring Light: This is a light source in the shape of a ring. The ring arrangement prevents shadows and gives an even illumination. They are used with stereo microscopes.
Slide: This is the glass plate on which the specimen is located. Some slides have one end frosted to allow for easier writing, others have a depression to hold some liquid, still others have smooth corners to remove sharp edges and prevent injuries.
Stage: This is the flat surface on which the slides are placed on. It can be moved up and down for focussing.
Stage Clips: These are clips that hold the slide.
Stereo: In optics, this refers to the ability to see depth (a 3-D image). Two separate eyepieces on a binocular head are not enough. You also need two separate objectives (as is the case with many stereo microscopes).
Student Proofed: Many microscopes used in schools are “student proofed”. This means that students can not remove parts of the microscope because special tools are required. Student proofed microscopes also have safety features like a rack stop and spring-loaded objectives.
T-mount: This is a standardiued adapter ring. It allows you to connect a photo camera to the microscope. Compare this to the C-mount, which is used to connect video cameras.
Tension Adjustment: A proper setting of the tension adjustment prevents the stage to automatically lower itself due to its own weight. If the tension adjustment is set too tight, then it is difficult to focus.
Trinocular Head: This microscope head has three exits, two for viewing (for binocular vision) and a third exit to connect a camera. Some microscopes also allow for taking photographs through a special adapter at the eyepiece, but a trinocular head offers more stability and is to be preferred for photographic work.
Widefield eyepiece lenses: These eyepieces cover a large field of view. More of the specimen can be seen when looking through them. This makes orientation easier.
X: The “X” stands for “times” as used in multiplication. It designates the magnification of the objective and the eyepiece. The total magnification is calculated by multiplying the magnification of the objective with the magnification of the eyepiece.