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Nomenclature & Functions
i--SPEED
13
11.
Back Focus Control
It is sometimes necessary to adjust the distance between the
C--mount face and the image sensor to accommodate lenses
from different manufacturers and lenses with different optical
tolerances. The Olympus
i--SPEED
has a back focus
assembly located in the front of the unit to permit this
adjustment.
To adjust the back focus, screw a C--mount lens into the
C--mount in the normal way. Turn the locking ring anticlockwise
(when viewed from the front) to unlock the C--mount thread ring
then rotate the lens to adjust the back focus as required -- a
series of ‘click’ positions will be felt. When complete, the
adjustment should be left in one of these ‘click’ positions and the
locking ring rotated clockwise to lock the C--mount thread ring in
position.
C--mount lens
Locking ring
As a guide, the correct setting of back focus is obtained by
pointing the camera at an object at a known distance from the
lens, preferably an “infinite” distance. The scale on the lens is
then used to set the focus ring to this distance. The back focus
is then adjusted to obtain the best image.
12.
Mounting Holes
The base of the unit is fitted with 5 standard mounting holes. It
is recommended that the central hole is used for mounting the
camera (e.g. to a tripod) and the other holes may then be used
to mount light--weight accessories to the camera.