10
5.5
Focusing
To obtain a sharp image at some other distances adjust the lens
focus (3, Fig. 1) leaving the eyepiece setting intact. You should
be able to obtain a sharp image for distances from 2-10m to
infinity.
If you wear eyeglasses or NBC protective mask, you may like to
fold the rubber eyecup.
5.6
Manual gain adjustment
NVS 15 goggles is equipped with the manual gain adjustment
handle. The light gain of the Image Intensifier Tube is set to the
level, at which it allows viewing in the darkest conditions. While
outside illumination increases at dusk, dawn, full moon or in the
environment with artificial lights, the tube enters the Automatic
Brightness Control (ABC) mode that automatically decreases
gain to keep the screen brightness on the same level thus
protecting both the tube and the observer’s vision. It leads to
situation when the contrast of the image (relation between the
brightest and darkest patterns on the screen) becomes lower, and
detection/recognition ranges become shorter. In order to prevent
deterioration of device performance under higher illumination
the user can rotate the manual brightness control knob counter
clockwise to restore full functionality. The brightness control can
be adjusted in the range of 20-100% .
