Technical Glossary for Binoculars



  • Doublet Field flattener
A double lens group that compensates for curvature of field, ensuring excellent image flatness and clarity.


  • Long eye relief
Allows users who wear glasses to see the entire image.


  • Optical Image Stabilizer
A computer controlled Vari-Angle Prism or lens-shift system that optically compensates for your movement and provides a much more detailed and clearer view.


  • Porro prism
A combination of right-angle prisms that ensures the image is the right way up for viewing. The use of prisms also shortens the distance between the objective and eyepiece lenses, reducing the size and weight of the binoculars.


  • Roof prism

Performs a similar function to the Porro prism, but can be fitted in a straight barrel for a streamlined appearance.

  • Rubber coating

Cushions the binoculars against shocks and makes them easier to grip.


  • Super Spectra Multicoating
Extremely thin layers of chemicals applied to the surfaces of selected lenses and prisms to reduce unwanted reflections. This improves image sharpness, contrast and colour balance.


  • Waterproof

Will survive temporary submersion up to one metre underwater for 5 minutes. Not suitable for use underwater.

  • Weatherproof

Can be used in rain or snow and rinsed in running water to remove mud and dirt.

  • Wide field of view

Binoculars with an apparent field of view greater than 65º are generally accepted as having a wider field of view and offer a broader perspective.