JM Optics Ltd
Binocular and Scope Specialists
|
The most important parts of a binocular are the lenses and prisms, the quality of these being the main factor in how binoculars perform and the price you pay. Prisms: The quality of prism is defined by its 'BaK' number. There are two different numbers, BaK7 and BaK4 - BaK4 being the better of the two. These ratings do not fully show how good the prisms are, a good BaK7 prism can be better than a poor BaK4 prism. Having said that they are still a very good indication of prism quality. A good BaK4 prism will create a very bright, crisp image. Lenses: The quality of lens and its coating also affects the image. Some more expensive binoculars have Aspheric Lenses which are specially moulded for superb edge definition. A good lens and coating reduces the reflection and thus increases brightness and crispness. Lens coatings can come in different colours, the most common are:
The more glass surfaces within a pair of binoculars which have coatings, the less light will be wasted and scattered by reflection, so the image can be brighter. More expensive binoculars can be fully multi-coated: all surfaces have various coatings. |