Frequently asked questions

Who should I contact if I want to have my Eschenbach binoculars repaired or I require spare parts or accessories?

If you have a technical service query, please contact your optician or specialist dealer who will make all the necessary arrangements with us. Dealer Search

I would like to buy a pair of Eschenbach Optik binoculars. Where are Eschenbach Optik binoculars available?

You can find Eschenbach binoculars at selected specialist dealers. Dealer Search

What do numbers like “8 x 32” or “10 x 42” mean?

The value “8 x” or “10 x”, for example, refers to the apparent magnification of an object. Eight times magnification means, for instance, that an object at a distance of 800 m appears as if it were only 100 m away.

The numbers “32”, “42” or “56”, for example, that follow the magnification value, refer to the objective diameter of the binoculars in mm. This value is an important performance feature for binoculars. The greater the objective diameter, the more light can be admitted and the brighter the image.

What effect does internal focussing have?

Focussing means adjusting the sharpness of the image. In the case of internal focussing, only the lenses inside the binoculars are moved. This provides a closed system which avoids dust, air or moisture from being drawn in.

What does the term “field of view” mean? What does “Ww” mean?

The field of view refers to the diameter of the image section at a distance of 1,000 m. For example, the value could be 130 m/1,000 m. The field of view is printed on all Eschenbach Optik binoculars.

The greater the field of view, the easier it is to view landscapes or moving objects, for instance at sporting events or when you’re observing wildlife. Lenses with the designation “Ww” have a particularly wide field of view. “Ww” = wide angle.

What is the near point of a pair of binoculars?

This number refers to the closest distance at which objects can be viewed sharply and without distortion when magnified. This is important when you’re using binoculars in a museum or for observing insects, for example, where viewing is at short range.

What is the difference between Porro prisms and roof prisms?

Binoculars with Porro prisms have the “classic”, wider design. As the lenses are further apart, conventional Porro binoculars offer slightly better stereoscopic depth perception at short distances.

Binoculars with roof prisms, on the other hand, are very compact and have a particularly slim design. They require a higher level of optical precision engineering than Porro prism binoculars of the same quality.  Porro binoculars are heavier than roof prism binoculars.

What is phase correction?

Due to the design of roof prism binoculars, a reduction in resolution can occur. To avoid this and obtain excellent resolution, a special coating, the phase correction, is applied to the prisms using a process called vapour deposition.

What is a coating and what are the most important coatings?

Full coating:  all air-lens surfaces are provided with an extremely thin anti-reflection coating to optimise the "light movement" (transmission) through the binoculars to the eye. In this case, the entire lens is coated.

Magenta or blue coating: a magnesium fluoride coating is, of course, standard.

Multi-layer or multi-coating: all lens surfaces are vapour coated with several or many layers of coating.

What does the information relating to exit pupil, geometric light intensity and twilight factor mean?

These arithmetical values are calculated from the ratio of magnification and objective lens diameter.

Important in practice: an exit pupil between 2 and 3 mm is sufficient for use in daylight. Binoculars with an exit pupil of 5 - 7 mm should be selected for difficult light conditions.

It is important to note that the geometric light intensity and twilight factor are not related to quality characteristics, such as coating and image quality.  This information can therefore only be used as a guide.

You can find further information on the precise values for Eschenbach Optik binoculars in the product overview.

What are BK-7, BaK-4 and SK15 prisms?

BK-7: prisms manufactured from boron crown glass. The standard for good image quality.

BK-4: these specially selected and carefully machined high-performance prisms manufactured from barium crown glass provide even better resolution of details and a brighter image with high colour fidelity.  

SK15: these prisms manufactured from very high quality SK15 glass are used for the farlux SELECTOR V. They minimise unwanted internal reflections and therefore provide a pin sharp image with optimum contrast.

Which binoculars are recommended for which specific purpose?

You can find product recommendations in areas of use

Why are some binoculars filled with nitrogen?

Waterproof binoculars from Eschenbach Optik are suitable for use in all types of weather and are filled with nitrogen (N2) to prevent fogging of the internal optics in the case of temperature fluctuations.