User's Manual

23
The lens nodal point is the point about which the lens may be rotated without causing
parallax, the lateral shift of the image. Several good tutorials on the web describe the
procedure for finding the lens nodal point:
http://dgrin.smugmug.com/gallery/2114189
and
http://archive.bigben.id.au/tutorials/360/photo/nodal.html.
Once the nodal point of a lens is found, its position can be noted, and the distance D2
between the nodal point and the focal plane of the camera should be recorded. This
procedure should be followed for all of the lenses to be used in the 3D rig.
3D Mode Set-Up on the HU3
The HU3 set-up for 3D operation requires that:
1. One camera is rotated about the entrance pupil of its lens so that its line of sight
intersects the line of sight of the second camera at a distance D1, as illustrated in the
picture on p-21.
2. The mechanical stops for the motorized adjustment of the inter-ocular distance are set
up so that one stop corresponds to where the distance D3 = 0, and the second stop is the
maximum inter-ocular distance.
3. The mechanical stops for the motorized adjustment of the convergence angle are set up
so that one stop corresponds to zero convergence angle (θ = 0), where the optical axes of
both cameras are parallel, and the second stop corresponds to the maximum angle of
convergence.
4. The user input three values:
a. The maximum value of the inter-ocular distance. This distance is entered on the
first line labeled Inter-ocular (see figure below left). The navigation key may be used to
highlight and change this distance value.
b. The maximum angle of convergence is entered on the second line.
c. The Camera Offset distance is the distance between the lens nodal point and the
camera focal plane and is entered on the third line.
Checking the 3D Set-Up
This procedure requires using a monitor that can superimpose the outputs of both
cameras.
1. After setting up the HU3 for 3D Mode as described in the preceding section, select a
focus ring:
a. Press the Menu key. Navigate to the Lens selection. Press the Ring softkey and
select a lettered ring that matches the approximate range of subject distances.
3D Set-up window