Achromat

An achromat is a special double lens that reduces chromatic aberration and provides a sharper image. High-quality binoculars use achromats to ensure a clear and color-accurate view.

Air-spaced achromat

In an air-spaced achromat, the lenses are separated by a fine air gap. This design allows for more compact binoculars while maintaining good optical performance.

Interpupillary distance (eyepieces)

The interpupillary distance describes the distance between the two eyepieces. It is adjusted individually until a complete, round image is visible.

Eyecups

Eyecups ensure the optimal distance between the eye and the eyepiece. They improve comfort, block stray light from the side, and can often be adjusted for eyeglass wearers.

Exit pupil

The exit pupil is the circle of light that emerges from the eyepiece. It affects how bright the image appears, especially in poor lighting conditions.

Calculation: Objective lens diameter ÷ Magnification

Roof prism binoculars

Roof prism binoculars are characterized by their slim and compact design. They are especially handy and ideal for use on the go.

Twilight factor

The twilight factor indicates how well details can be recognized in low light. It is mainly used to compare different models.

Calculation: √(Objective lens diameter × Magnification)

Diopter adjustment

Diopter adjustment compensates for differences in vision between the two eyes. This allows the image to be focused individually.

ED glass

ED glass (Extra-low Dispersion) reduces color fringing and improves image sharpness. It ensures especially high-contrast and detailed images.

Binoculars with compass

Some binoculars come with an integrated compass. These models are especially suitable for navigation, outdoor use, and marine applications.

Galilean binoculars

This design does not use prisms and is nowadays mainly found in opera and theater glasses. It offers a wide field of view but is limited to low magnifications.

Rubber armoring

Rubber armoring protects the binoculars from impacts, moisture, and wear. It also provides a secure and non-slip grip.

Rubber eyecups

Rubber eyecups offer high comfort and protect against stray light entering from the side. Many models can be adjusted so that eyeglass wearers can also use the full field of view.

Collimation (double image)

Collimation refers to the precise alignment of the two halves of the binoculars. If the binoculars are misaligned, a double image may occur, which can cause eye strain.

LE eyepiece (Long Eye Relief)

LE eyepieces provide greater eye relief and allow eyeglass wearers to view the entire field of view comfortably.

Light intensity

Light intensity describes how bright the image of binoculars is perceived. It is especially important for observations at dusk or in poor lighting conditions.

Light intensity (geometric)

Geometric light intensity is a calculated value used to estimate image brightness. Optical quality features such as coatings are not taken into account.

Calculation: (Objective lens diameter ÷ Magnification)²

Light intensity (relative)

Relative light intensity takes modern technologies such as multi-coating and high-quality glass into account. This provides a more realistic estimate of actual image brightness.

Multi-coating

Multiple coating layers on the lenses reduce reflections and improve light transmission. The result is brighter and higher-contrast images.

Night binoculars

Night binoculars are designed for poor lighting conditions. Models with high light intensity are particularly suitable for observations at dusk and at night.

Image intensifier

Image intensifiers are electronic devices that amplify available residual light such as moonlight or starlight. They allow observations in darkness, but do not achieve the natural image quality of classic optics.

Ruby coating

A reddish coating on the objective lenses increases contrast in bright light. At the same time, the overall light transmission may be slightly reduced.

Field of view

The field of view describes the width of the visible area at a distance of 1,000 meters. A wide field of view is especially advantageous when observing moving objects.

Tripod adapter socket

Many binoculars feature an integrated tripod thread. With a suitable adapter, the binoculars can be mounted securely, providing a steadier image.

Lens coating

Coatings are special layers on the lenses that reduce reflections and increase light transmission. This results in brighter and higher-contrast images.

Magnification

Magnification indicates how much closer an object appears. A 10x binocular makes an object appear ten times larger than with the naked eye.

Waterproof & nitrogen filling

Waterproof binoculars are protected against moisture. Nitrogen filling also prevents the lenses from fogging up on the inside.