Optical Terms for Better Understanding the Optics You Want To Buy

There are many terms in optics and familiarizing with them and going through binoculars reviews could help you in getting to know the particular device better and use it easily. The most commonly and not so common terms about binoculars and their meaning can help you take an informed decision to purchase the right binoculars to match your requirements.

Some Important and Unusual Terms:
Abbe-Koenig is a prism made of two glass prisms sealed together forming a symmetric V-shaped shallow assembly. The internal reflection flips the image both vertically and horizontally so that you finally see an erect upright image.

Abbe Number of a glass and other materials tells what the amount of dispersion will be for a spectral range in particular.

Aberrations are terms used in connection to - Spherical Aberration, Chromatic Aberration Curvature of Field, Coma, Distortion, and Astigmatism. Corrected aberrations helps making best binoculars.

Amici Prisms are a type of ‘roof prism’ ideally used in best spotting scopes.

Anomalous Partial Dispersion Glass also called extra-low dispersion glass/ED glass enables to combine different glass types and design lens to obtain the color correction desired.

Apochromatic Lens/APO is a lens usually of three elements to bring light of three different frequencies to a common focus and has better correction of chromatic aberration as well as spherical aberration.

Aspheric Lenses is a non spherical for reducing or eliminating spherical aberration and decrease other optical aberrations.

Blacking Out or Vignetting is a dark area around the periphery of the field of view and reduces image brightness or saturation compared to the image center.

Body Shape is the shape of the binoculars due to the variations on the main Roof Prism or Porro Prism designs namely - ZCF, BCF, BWCF, DCF, MCF, or UCF.

Chromatic Aberration or Color Fringing or chromatic distortion happens when lens fails to focus all colors to the same convergence point.

Depth of Field is indirectly proportional to magnification.

Diopter Adjuster is a separate eyepiece-focusing tool on the right lens of your binoculars for Dioptric Correction to correctly focus your binoculars.