Alignment Checklist

Use a 3D monitor with Anaglyph viewing mode to perform fast & precise alignment. The anaglyph viewing mode is a robust tool to monitor all stereoscopic parameters during shooting.

1. Check camera orientation: In order for the rolling shutters of the two digital cameras to operate in the same direction, make sure one of the cameras is mounted upside down. Tango provides dedicated inverter blocks for the Mini 2K SI, the RED One, the Sony HDC?P1, the Sony F23/F35, the ARRI ALEXA.

2. Install & lock both cameras with lenses onto the 3D Stereo Tango rig, set the interocular distance to zero. Keep the interocular at zero during the entire alignment checklist.

3. Check the distance between the beamsplitter and the two cameras: set the adjustable stop blocks at the same value for both the left & right eye, make sure each camera is pushed against their respective stopping block.

4. Check the vertical alignment of the optical centers: look into the matte box straight through the beamsplitter with one eye only, the two lenses should overlap, no vertical offset. If there is a vertical offset, use the large silver thumbwheel behind the top camera to move it up or down until the two lenses overlap perfectly along the vertical axis.

5. Check tilt alignment: looking at a distant landmark on the 3D monitor, use the tilt adjustment knob on the bottom camera to make the left & right images overlap perfectly on the vertical axis. Then check this alignment looking at an object 5ft away from the rig, if there is now a vertical offset between the left and right images, adjust the optical centers as described in step # 4 and re?do step #5.

6. Check roll alignment: looking at horizontal structures on the 3D monitor, if on the left side of the picture a red border above light?toned elements appears, it means the bottom camera (left) leans to the left. Using the two silver knobs located on either sides of the roll stage under the bottom camera, adjust the roll until the left & right images overlap perfectly across the frame on the vertical axis.

7. Check convergence alignment: look into the matte box straight through the beamsplitter with one eye only, the two lenses should overlap, no horizontal offset. If there is an horizontal offset, use the convergence knob beside the bottom camera to adjust the angulation until the two lenses overlap perfectly along the horizontal axis. Then look at a distant background object on the 3D monitor; turn the convergence knob until the make the left & right images overlap perfectly on the horizontal axis. The left & right cameras are now parallel.

8. Check viewing angle alignment: If you are not using perfectly matching prime lenses, you may notice on the 3D monitor a slight magnification disparity. Point the rig at a round object: the object will appear slightly larger on one eye than on the other. This is a magnification disparity, which translates into a disparity of viewing angle between the two lenses. To suppress this disparity, move the bottom camera closer or further away from the beamsplitter until on the 3D monitor the magnification is the same for both eyes.

Note to the reader: for fine?tuning purposes, all of the adjustments described above can be also applied to the top camera. The 3D Stereo Tango provides six independent axes of alignment for the top camera and for the bottom cameras.

The ROLL, TILT & CONVERGENCE adjustments are all pivoting on the beamsplitter at intersecting point of optical axis of the left & right cameras. The ROLL, TILT & CONVERGENCE adjustments can be done manually or can be motorized.