Vinten Radamec Free-d - Manual (Page 26)

Vinten Broadcast Ltd free - d ™ Installation Manual V1.4.4
Page 26 of 46
between the free-d ™ camera and the reference point on the studio lens has
been entered correctly; if the offset is correct the problem is probably one of
nodal shift.
Repeat the test with different settings of zoom and focus. If the view angles
match at some settings but not at others, a nodal shift error is probably
responsible. This may require alteration to a studio lens calibration file.
Because a large error in the offset values or nodal shift can affect the
apparent view angle at all distances, it may be necessary to repeat the
Horizontal View Angle section above.
7.11 Pan adjustment
Initially ensure that the virtual and real objects used for the previous test are
aligned as seen in the image. Check that the objects are still co-sited by
viewing them from two different directions, 90 degrees apart; if necessary
move one of the objects to achieve this. Now move the camera to view the
objects from a diametrically opposite direction (ie, such as the camera’s pan
angle is 180 degrees from what it was before).
If the objects are no longer aligned horizontally, this indicates that free-d ™
camera is rotated from its correct orientation about the vertical (pan) axis. To
correct this, loosen the camera’s mounting screws and rotate it around the
vertical axis so as to halve the positional error. Now reposition either the real
or the virtual object so that they are coincident as seen in the image. Once
again view the objects from the opposite side to see if they remain aligned,
and if not repeat the adjustment. Once the alignment is correct fully tighten
the mounting screws: note that this adjustment is very critical!
7.12 Tilt adjustment
Position a real object and a virtual object (ideally something like a thin
horizontal bar) so that their vertical alignment can be judged. View the objects
from as short a distance as possible, with the tilt set at zero, and adjust the
vertical position of the real or virtual object so that they align. Now track the
camera backwards, and note whether there is any vertical shift (slippage)
between the objects as the camera-object distance increases.
If a significant degree of shift is observed, the free-d ™ camera needs to be
tilted forward or backward (ie, around the X-axis). This can be achieved by
rotating the ‘wedge rings’ that form part of the base plate of the camera,
although the tilt and roll cannot be adjusted independently by this means.