Providing diverse optical technologies.
Supporting the enjoyment of viewing; Nikon’s starting point.
Nikon binoculars are highly acclaimed for their superior image quality. This is realized by Nikon’s comprehensive optical technologies. For example, based on our various coating technologies, multilayer coating is used to increase brightness. “Extra-low dispersion (ED) glass” effectively compensates chromatic aberration employing our optical glass manufacturing techniques. While the “Field Flattener Lens System” provides sharp and clear images all the way to the lens periphery as a result of its outstanding optical design.
Nikon’s wide-ranging technological power helps to deliver the most memorable and emotional viewing experiences in a broad spectrum of situations such as birdwatching, stargazing, marine observation, climbing, nature watching, travel, sports spectating, and theater.
Part of the light that passes through a lens is lost because of reflection by the front (incident light) and rear (exiting light) surfaces. The more light reflected, the lower the amount of light passing through the lens, causing the image to appear darker. Also, such reflected light may result in ghosting and flare, affecting image contrast. To minimize reflection on the lens surfaces and ensure clear, sharp images, Nikon applies antireflective coating on transmitting surfaces of the lens (front and rear).
There are two main types of coating: single-layer and multilayer. A multilayer coating effectively reduces reflected light that cannot be eliminated with a single-layer coating, and increases the transmittance of light.
Visible light is composed of various wavelengths. Gathering these into a precise point is the ideal result for objective lenses.
With a single lens, because light is bent in the same way as with a prism, the focal lengths of different light wavelengths vary. As a result, not all light rays reach exactly the same point, which causes chromatic aberration.
An achromatic lens made with conventional glass materials can match focal lengths of two different wavelengths. For red and blue colors, for example, that contain both ends of the wavelengths of visible light, chromatic aberration can be reduced to a certain extent by conforming their focal lengths. However, with more detailed examination, because light with other wavelengths such as green has different focal lengths, residual chromatic aberration results. This residual chromatic aberration is known as secondary spectrum.
Combinations of conventional glasses cannot solve this secondary spectrum problem, so particular optical materials which have a unique characteristic of dispersion are needed.
ED (Extra-low Dispersion) glass has this unique characteristic and when combined with other glasses minimizes the effects of the secondary spectrum. Compared to achromatic lenses, ED glass reduces chromatic aberration to a remarkable degree.
Field Flattener Lens System
In the case of a lens fully compensated for coma aberration and astigmatism, the light rays coming from a point apart from the optical axis are focused at one point. But this point is not always included in the vertical plane to the optical axis. This is called curvature of field. With a lens producing this aberration, when focusing on the center of the field, the periphery of the field appears out of focus. This can cause very negative effects especially on wide-field-type binoculars.
Nikon’s Field Flattener Lens System is an optical system that minimizes the curvature of field across the entire optical system. This advanced lens design provides consistent, edge-to-edge sharpness while compensating astigmatism and coma aberration at the same time. Observation can be enjoyed with a sharp and clear image throughout the entire field of view.