A

Angle of view/Field of view
The angle of view is measured in degrees and reflects how wide an area you will be able to see  with the binoculars. It is also referred to as the field of view, and can be expressed as the width  of the viewing area in metres when viewed from a distance of 1000 metres. A wider field of view  makes it easier to observe sports events, wildlife and other moving subjects. With the 8x25 PC I  for instance, the field of view is 105 metres at 1000 metres. But with the 7x35 DPS I it is 162 metres  at the same distance.

Augen-Okular-Abstand und verstellbare Okulare
Ein großer Augen-Okular-Abstand ermöglicht es Brillenträgern, den gesamten Bildausschnitt zu sehen, auch ohne ihre Brille abzunehmen. Verstellbare Okulare können nach oben und unten justiert werden, um das Beobachten noch komfortabler zu machen.
Nach oben und unten verstellbare Okulare: EXWP I, EXPS I, WP I,
PC I & Zoom PC I, RC I

Austrittspupille
Die Austrittspupille ist der Durchmesser des Lichtkreises, der durch das Okular zu sehen ist. Je größer das Bild, desto mehr ist auch bei geringerem Licht zu erkennen. Die Größe der Austrittspupille kann in Millimetern bestimmt werden, indem man den Durchmesser des Objektivs durch die Vergrößerung teilt. Eine Austrittspupille von 2 bis 3 mm ist ausreichend für den Einsatz bei Tageslichtbeobachtung, bei geringerem Licht sollten Ferngläser mit Austrittspupillen von 5 bis 7 mm verwendet werden.
z.B. 8x42 Ferngläser: 42/8 = 5.3 ➜ Austrittspupille = 5,3 mm

Aspherical lenses
Precisely tooled aspherical lens elements prevent distortion and guarantee plasticity, sharp contours and bright pictures. Aspherical lens technology is used in numerous OLYMPUS binoculars.
 

B

Blickwinkel
Der Blickwinkel wird in Grad gemessen und gibt an, wie groß das mit dem Fernglas überschaubare Feld ist. Man bezeichnet dies auch als Sehfeld, es wird dann als Breite des überschaubaren Feldes in 1000 m Betrachtungsabstand angegeben. Ein größeres Sehfeld erleichtert die Beobachtung von Sportereignissen, wilden Tieren und anderen sich schnell bewegenden Objekten. Bei dem 8x25 PC I beispielsweise beträgt das Sehfeld 105 Meter bei einer Entfernung von 1000 Metern. Bei dem 7x35 DPS I jedoch beträgt es 162 Meter bei derselben Distanz.

BaK-4 prisms and lenses
Precisely ground prisms and lenses made of brightness-enhancing barium crown glass (BaK-4) ensure clarity and brightness to the very edge of the field of view. OLYMPUS offers an extensive range of high-quality binoculars with BaK-4.  

C

Coating
A thin layer of a substance which is usually evaporated and baked on the lens surfaces to reduce reflection and increase light transmission.

Contrast
The difference in intensity between the lightest and darkest image viewed through the optical system.

D

Diopter adjustment
All OLYMPUS binoculars have a central focusing knob, plus a separate diopter adjustment mechanism on one eyepiece. This individual eyepiece adjustment permits users to compensate for vision differences between their eyes and will produce in-focus images for each eye.

De-alignment
An indication that the lenses are jarred out of position, decreasing the quality of viewing.

E

Eye Relief and adjustable Eyepieces
This describes the distance from the eyepiece to the surface of the eye where the full image can be viewed. If you wear glasses, it is best to choose a pair of binoculars with long eye relief. Adjustable eyepieces can be twisted up and down  to further enhance comfortable viewing.

F

Fixed focus
An optical instrument lacking the ability to change focus.

Fixed power
A binocular scope with a single magnification setting.

H

HD (High Definition) Glass or ED (Extra-low Dispersion) Glass
Optical glass processed to greatly reduce aberration and provide better color reproduction.

L

Lens
One or more pieces of optical glass with surfaces curved to converge or diverge transmitted light rays.

Lenses
Some Olympus binoculars feature an Extra Low Dispersion (ED) glass lens element. This reduces chromatic aberration, a common problem at high magnification, to produce sharp, clear images. Other Olympus models contain an aspherical glass lens element. This also provides an extremely high degree of optical resolution, reducing distortion.

Lens coatings
A variety of coatings can be applied to the lenses to reduce reflection and enhance light transmission. The more coatings, and the greater the number of lenses coated the better the image will be.

O

Objektivdurchmesser (Frontlinse)
Der Objektivdurchmesser wird in Millimetern angegeben und ist eine wichtige Angabe für die Leistung eines Fernglases. Je größer der Durchmesser, desto mehr Licht kann in das Fernglas eintreten und desto heller wird das Sehfeld. Je größer der Durchmesser, desto schwerer und größer wird auch das Fernglas.

P

Parallax
An optical illusion that causes a viewed image to apparently change position as the viewer's eye moves to either side of the eyepiece.

Prisms
The prisms in the high-performance binoculars are coated to preserve brightness and image detail. They are ground from  BaK-4, a type of optical glass that refracts very little light for great image clarity. Two different types of prism are employed.  Porro-prism binoculars feature an off-set barrel design. The wide space of the objective lenses enhances the perspective by giving more depth of view and creates an impression of more three dimensional images. Because of this, the porro prisms binoculars are usually slightly bigger than roof prisms models. A roof-prism system reduces the amount of space needed by directing light through a smaller area, which also makes the binoculars lighter and more compact.
Roof-Prism Binoculars: EXWP I, WP I, RC I    Porro-Prism Binoculars: EXPS I, DPS I, ZOOM PC I, PC I, DPC I

R

Relative brightness
Directly related to the exit pupil size, this also indicates how well binoculars will perform in low-light situations. The relative brightness index is equal to the square of the exit pupil size. A high number means better viewing in low light conditions.

T

Twilight factor
A unit of optical comparison calculated by multiplying magnification by objective lens diameter, and taking the square root of the product. The greater the twilight factor, the better the binocular can provide quality viewing under reduced light conditions.

U

UV Protection
All OLYMPUS binoculars provide protection against harmful UV rays as they use special coatings or lenses.

V

Vergrößerung
Die Vergrößerung bezieht sich auf die scheinbare Vergrößerung eines beobachteten Objekts. Ein Objekt in 1000 m Entfernung wirkt bei einem 10x Fernglas so, als befände es sich nur 100 m entfernt.

Variable power
Magnification that can be adjusted.

W

Wide angle
Wide angle field of view  allows to spot fast moving objects.
10 x 50 DPS I, 8 x 40 DPS I, 7 x 35 DPS I have 30 % wider view.

Z

Zoom
OLYMPUS bietet Ferngläser mit Zoomfunktion, deren Zoombereich zwischen 8-16x und 10-30x Vergrößerung liegt.