Understanding Binoculars, Optical Coatings, Focusing

Understanding Binoculars - Bightness, Prisms, Contrast, Resolution

Understanding Binoculars - Exit Pupil,  Field of View, Eye Relief, Near Focus

Understanding Binoculars - Magnification, Objective Diameter

The binoculars optical coatings play an important role in the quality of image. Coated lenses ensure an even light transmission through the binoculars which results in a clear, sharper image.

There are 4 basic types of coating with the most basic binoculars having no coating at all. With uncoated lenses less than half the light is transmitted through the binoculars which will significantly impact on the quality of the image, delivering an excessive amount of glare and low image contrast. Binoculars with uncoated lenses are not recommended.  

• Coated means that one or more of the lenses are coated, with a single coat, which offers little improvement over uncoated lenses. The overall image quality with binoculars that are just ‘coated’ is poor.
• Fully Coated means that all glass surfaces (that are exposed to air) are coated with a single anti-reflection layer. The image quality provide by such binoculars is acceptable for most users.
• Multi-coated means that one or more surfaces are coated with multiple layers of anti-reflection coating and the other surfaces are coated with a single coating. Multilayer coatings increase light transmission and improve image quality which will result in brighter, sharper images.
• The best quality binoculars are fully multi-coated which means all surfaces exposed to air have multiple anti-reflection coatings. Fully multi-coated lenses maximise the amount of light that is transmitted through the binoculars resulting in the greatest image clarity.

Focusing – binoculars require a focusing mechanism to enable them to focus on objects of varying distances, most binoculars either come with individual focusing or central focusing.

• Binoculars with individual focusing enable each eyepiece to be rotated independently. Individual focusing is the most precise form of focusing.
• Binoculars with central focusing have a single focusing wheel to achieve the correct focus. The down fall of central focusing is that peoples vision differs from eye to eye and therefore a diopter adjustment is required to enable one eyepiece to be individually focused. 
  

Bird Watching Binoculars / Astronomy Binoculars / Compact Binoculars