Glossary of Terms

Below you will find definitions of terms used in our website and in microscopy in general.

  • Achromatic lens: a lens that is specially designed and coated to correct for the tendency of light to separate into colors when passing through glass. An achromatic lens corrects this such that colors are more accurate after being magnified.
    Top
  • Binocular microscope: A compound microscope with two eyepieces viewing down a single optical channel and objective. This is different than a stereo microscope, which has a separate optical channel for each eye. 
    Top
  • C-mount & CS-mount: Also referred to as C/CS-mount, it is a threaded standard developed for mounting a lens to a camera. The mount is most commonly used for video cameras (i.e., CCTV cameras, not camcorders), and is used to mount cameras to microscopes. The mechanical definition of both standards is 1" diameter, 32 TPI (threads per inch), male on the lens (or microscope) side and female on the camera side. The optical definition of the C-mount is that the image reaches the focal plane, or camera's detector, at 17.5mm past the edge of the lens' (or microscope's) mounting threads. The CS-mount is identical in all respects except the focal plane is 12.5mm past the mounting threads. A CS-mount camera can be mounted on a C-mount lens or microscope by using a 5mm extension ring. See also: T-mount.
    Top
  • Coaxial Controls: A configuration where one knob is centered on top of another. For example, coarse and fine focus may have a larger coarse focus knob with a fine focus knob on top of it (so the center of both knobs is on the same axis). Also commonly used for Mechanical Stage X/Y movement knobs.
    Top
  • Compound microscope: A microscope with multiple lenses, however this definition describes virtually all modern microscopes. It would typically include multiple user-selectable objective lenses of varying magnifications and present a two-dimensional view. Also see: stereo microscope.
    Top
  • Condenser: The light rays from the illuminator are condensed and focused through this lens in the center of the stage, providing better image resolution.
    Top
  • Digital microscope: A microscope and video camera combination with a digital output such as USB or firewire. The microscope often includes software to display the image on a PC.
    Top
  • DIN Standard Objectives: (Deutsches Institut fuer Normung) An international standard which dictates the design compatibility of the objective lens. DIN standard objectives from one manufacturer can be used in another manufacturer's DIN standard compatible microscope.
    Top
  • Doublet lens: a lens design that is actually two different lenses cemented together (usually one positive magnifier and one negative). This design is used in widefield eyepieces to obtain significantly better color performance than single lens designs.
    Top
  • Dual-view microscope:  A monocular microscope with a second, vertical viewing port. The vertical port can be used with an eyepiece for a second person, such as an instructor, to view the specimen, or it can be used with an adapter and a video or still camera. See also: trinocular microscope.
    Top
  • Eyepiece or Ocular: The lens closest to your eye when looking through a microscope. A binocular or stereo microscope will have two, a monocular microscope will have one. The lensalso plays a critical role in the total system magnification. See also widefield eyepiece.
    Top
  • Eyepiece Tube or Eyetube: The tube into which the eyepiece lens (ocular) is set. This is usually presented at an angle for comfortable viewing. It may also be mounted in a vertical position such as on a trinocular or dual-view microscope for either a second viewer, or for a camera designed to fit inside an eyetube.
    Top
  • FPS: frames per second: Used to indicate the speed in which a video image is refreshed and displayed on a monitor. In video microscopy this is usually controlled by the camera. The faster the refresh rate (number is larger), the "smoother" any movement of the specimen will appear.
    Top
  • Interpupillary Distance: Distance between the two eyepieces. Typically it is adjustable to accommodate different users. Some microscopes also have graduated scales to indicate the actual distance between the eyepieces, allowing a user to determine the optimum number and then quickly set it before each use.
    Top
  • Koehler Illumination: A highly effective illumination design.
    Top
  • Magnification: Multiply the magnification of the eyepiece by the magnification the objective lens for the total magnification at that power. 400x or 1000x is necessary for studying cells and cell structure.
    Top
  • Mechanical Stage: A mechanism mounted on top, or as part, of the stage that allows the operator to move the specimen slide in the X or Y direction by turning a knob. Very useful at higher magnifications as it can be difficult to move the slide by hand. Most mechanical stages come with a graduated scale so you can see how far the slide has been moved or keep track of the position of various objects on the slide.
    Top
  • Objective lens: The lens in a microscope closest to the specimen. In a compound microscope there are usually 3, 4 or 5 objective lenses allowing a selection of magnification levels.
    Top
  • Oil Immersion lens: A lens designed to be immersed in oil. A drop of immersion oil is placed on top of the cover glass and the lens is slowly lowered until it rests in the oil. This allows the light to pass through oil rather than air, and at higher magnifications results in a crisper, higher contrast image. Primarily seen on more advanced systems.
    Top
  • Parcentered: A lens design such that specimens that appear centered in the field of view at one magnification level will also appear centered when the magnification level is changed. See also: parfocal
    Top
  • Parfocal:  A lens design such that specimens that appear in focus at one magnification will also appear focused when the magnification level is changed. The depth of field (how much of a specimen's height will appear in focus at one time) changes significantly when magnification is changed. The higher the magnification, the shallower the depth of field. See also: parcentered
    Top
  • Phase Contrast: A technique using special objectives and condenser system to enhance the contrast of unstained, relatively transparent specimens such as blood and other tissue cells, thereby allowing microscopic viewing of living tissue. It is a sophisticated technique that shifts the light "phase" 1/4 wavelength, causing any light deviated by the specimen to appear dark on a light background.
    Top
  • Rack Stop: A safety feature consisting of a mechanical stop, typically adjustable, which prevents the objective lens from hitting the microscope stage.
    Top
  • Seidentopf: a head design where the interpupillary adjustment (increasing or decreasing the distance between the eyepieces) is achieved by twisting the eyepieces in an up and down arc motion like binoculars.
    Top
  • Slip Clutch: A safety device usually located on the focus knob allowing the knob to "slip" and continue turning when it reaches the end of its travel, or if it runs into the stage. Due to the gear ratios involved, without this it may be possible to damage the mechanism by applying too much force to the knob after it has reached the end.
    Top
  • Stage: The platform that holds the slide up beneath the objective lens.
    Top
  • Stereo microscope a.k.a. dissecting microscope: A microscope with a separate optical channel for each eye (eyepieces and objectives) which allows viewing in three dimensions. See also: compound microscope.
    Top
  • Turret or Objective Turret: The rotatable metal piece into which the microscope's objective lenses are attached. A "turret" style stereo microscope refers to the type that has more than one objective lens which can then be rotated into position. On a compound microscope the turret is the ring holding the objective lenses allowing the operator to rotate them into position as needed.
    Top
  • T-mount: A photographic mechanical mounting standard developed in 1957 originally intended as a universal lens mount for 35mm cameras. There are now T-mounts available for a large variety of digital and film cameras making it a good method for mounting cameras to microscopes. The thread (a.k.a. T-thread) is specified as 42mm diameter and 0.75mm pitch, or M42-.75. See also: C-mount
    Top
  • Trinocular microscope: A binocular microscope with a third, vertical viewing port. The vertical port can be used with an eyepiece for a second person, such as an instructor, to view the specimen, or it can be used with an adapter and a video or still camera. Click here for an example. See also: dual-view microscope.
    Top
  • Widefield eyepiece (WF): an eyepiece with an achromatic doublet lens designed in such a way that itdoes not have to be limited to viewing only in its center, and the portion of the lens that allows non-distorted viewing is larger than a normal lens. This appears to the user as a bigger aperture or "hole" to look through. It therefore has the advantage of being easier to use and more forgiving of a user's head movements. An eyepiece listed as WF10X/18mm would indicate it has a widefield achromatic doublet lens, 10X magnification and is 18mm in diameter.
    Top


Copyright © 2017 Leonhard Instrument Company. Powered by Zen Cart