5
Adjusting the focus
Look through your binoculars with your right eye closed. Now adjust the image for your left eye by turning
the centre wheel (6) until it is sharp and clear. Close your left eye and adjust the image for your right eye by
turning the dioptre ring (3) until it is also sharp and clear.
Mounting the binoculars on a tripod
Your binoculars have a threaded tripod connection (9) built in. The required tripod adapter is available as
an optional accessory (Art. No. 1916001). With this accessory, you are able to mount your binoculars on all
BRESSER tripods with a DIN mounting thread (e.g. Art. No. 4922100).
Binoculars ABC
MAGNIFICATION
The magnification value always is mentioned first in the model name (e.g. 10x42). With a magnification of
10x, the observed object appears one-tenth of the distance away that it really is.
OBJECTIVE DIAMETER
The lens pointing towards the object is called the objective lens. In the model name (e.g. 10x42), the sec-
ond number stands for the objective diameter in millimeters. The objective lens diameter is an indicator of
the amount of light that can enter the binoculars.
An objective diameter of 20 mm is sufficient for observations during the day. In twilight conditions, an ob
-
jective diameter of 50 mm or larger is recommended, as the lenses can gather much more of the remaining
light.
TRANSMISSION
The value of the ability to let light pass through optical systems is called transmission.
OCULAR
The ocular is on the side of a pair of binoculars pointing towards the eye and is often composed of three
to six single lenses that form an achromat. The ocular is one of the factors that determines optical quality
(i.e. color fidelity, sharpness and image distortion).
EYEPIECE FOR SPECTACLE WEARERS
An eyepiece for spectacle wearers allows for a full field of view with and without eyeglasses. Its main aim
is the adjustment of the distance from the eye to the ocular (eye relief). When an observer sees a circular
image through the binoculars, the eye relief is set correctly.
BINOCULAR
Optical systems with two oculars are called binocular (hence the name binoculars).
MONOCULAR
Optical systems with one ocular are called monocular.
