Analytik Jena DOCTER compact 8x21 Mode D'emploi page 7

Distance adjustment
To observe an object at different distances both clearly and in high contrast it is
useful to adjust binoculars to a special distance. While observing the object the
midwheel (2) has to be turned right or left till the clearest and richest in contrast vision
is reached. An adjustment of the Focusing and defective sight assistance is not
nessesary.
Eye piece adjustment
The binoculars are models for spectacle wearers. Normal sighted people employ the
binoculars with twist-up eyecups. Wearer of glasses just turn the eyecups down to
use the complete panorama of binoculars.
Maintenance and Protection
Prism binoculars do not need special care, they are nearly of attendance. If
necessary the outer lens surfaces should be cleaned with a fine hairbrush or a soft
piece of cloth. Coarse dust should remove through wash or blow before wiping. Do
not use chemical solvents and keep it in dry place!