This arrangement provides a mechanism to adjust centration of the camera lens over an
eyepiece when one is fitted. When the desired centration position is found the mount can
be fixed in this position by tightening the two ‘thumbscrew’ nuts against the flat part of the
camera heat sink enclosure using the adjustment screw tightening / loosening tool (item 3
in figure 1.1). This is done by inserting the metal hexagonal part of the tool into the
hexagonal depression in the thumbscrew nut and rotating the tool with your fingers to
tighten or loosen the thumbscrew nut (figure 3.10).
Do not over-tighten or you may
damage the tool
– only tighten enough to prevent accidental movement of the mount off
the desired XY centration position.
Figure 3.10 Using the adjust tool to fix the desired XY shift position of the adjustable mount. Left: Mate the
hexagonal part of the tool into to the hexagonal socket on the thumbscrew nut. Right: Turn the tool to tighten
or loosen the grip of the thumbscrew nut. Take care to avoid over-tightening or the tool may be damaged.
Eyepiece clamp
The eyepiece clamp is only required when using the camera with an eyepiece – you
should not fit it if you are using the camera for ordinary or macro photography with its own
in-built lens because it will obstruct part of the peripheral field of view.
To fit the eyepiece clamp first thread the lock nut onto it (item 5 in figure 1.1). For use with
some eyepieces this lock nut needs to be positioned near the top of the thread (e.g. for
use with some modern Leica eyepieces) and for others it should be positioned right down
as far as it will go (see figure 3.11). The position of this lock nut determines the minimum
distance of the sensor from the eyepiece and different eyepieces have different ‘eye-point’
distances (eye-relief distances) so this lock nut allows to adjust for those differences.
After this, screw the clamp with its lock nut onto the mount on the camera (figure 3.12).
OptArc AF51 Camera Page 37 of 99 User Guide v1.02
