Wednesday, October 17, 2012

Microscopes 101

Microscope lingo can have any first-time user or owner confused. Swift has put together a list of basic definitions that will have you understanding your microscope and sounding like a seasoned scientist in no time!
  • Chromatic Aberration: When lenses fail to focus two different parts of the spectrum in the same focal plane, they suffer from chromatic aberration.
  • Condenser: The function of the condenser is to provide full illumination to the specimen place and to enhance the resolution and contracts of the object being viewed.
  • DIN Optics: A German Standard for the manufacturing of microscope lenses. Optics are interchangeable from one DIN microscope to another. (DIN: Deutsche Industrial Normen)
  • Diopter Adjustment: The ability to adjust the focus for one eyepiece in a binocular or trinocular microscope to compensate for the different in vision between the user's eyes.
  • Focal Length: Parallel rays of light after refraction through a lens will be brought to a focus at the focal point. The distance from the optical center of the lens to the focal point, in the focal length, or focus.
  • Numerical Aperture (N.A.): A measure of the light gathering capabilities of an objective lens. The concept is comparable to the F-value in photographic lenses. In general, N.A. values less than 1.00 are dry objectives, while values greater than 1.00 require oil as a medium. The N.A. value can be found on individual objectives. NOTE: Condenser lenses are part of the optical system and are also assigned a N.A. value. The condenser system on a scope should match the N.A. of the highest power objective on the microscope.
  • Parfocal/Parcenter: A microscope system that is parfocused/parcentered enables the user to switch objective lenses (change powers) and still have the specimen in focus and centered in the field of view.
  • Working Distance: The distance between the front lens of the objective and the cover glass when the lens is focused on the specimen.