Newcon Optik NVS 7-4X - Manual (Page 17)

14
Focusing
To obtain sharp image at other distance adjust the lens focus
(2)leaving eyepiece setting intact. You should be able to obtain a
sharp image for distances from 2-20 m to infinity, depending on
the objective lens magnification.
If you wear eyeglasses or NBC protective mask, you may like to
fold the rubber eyecup.
Interpupillary distance
The unit is designed to accommodate interpupillary distance of
57-73 mm without any additional adjustment and should be
comfortable for 99% of adults.
Installation of interchangeable lenses
Do not apply an excessive force when changing the lenses.
1. Make sure the unit is off (1).
2. Remove the lens cap
3. Detach the current lens: hold the lens by its base and
rotate it counter-clockwise. Once the lens has been
removed, store it in a safe, clean space.
4. Screw in (clockwise) new lens.
The threads are very fine (to prevent humidity penetration) and
can be damaged easily. Do not apply force to the lens rotation. If
lens does not screw in smoothly make sure that the threads
match.
Unit is ready for operation immediately after the lens change.