How do the "asymmetric" movements on the P/P2/X cameras affect the movements when using a digital back that is mounted in the center of a board that is mounted on the rear standard (like a Kapture Group live video digital back adapter)?
In this cases the tilt and swing axis are out of the sensor plane, in all regards. Tilt and Swing, resp. sharpness will be affected, since when one wants to use these assymetrial axis to set a precise sharpness plane, it needs to select points lying on these axis (a point on H for horizontal tilt or a point on V for vertical swing) AND in the image (sensor) plane, which would be impossible in this case.
Will tilts and swings on the front standard change the composition with a digital back mounted in the center of the rear standard?
It theoretically changes the view point, since the lens is moved when one moves the front standard, and the tilt and swing axis do not lie in the optical center of the lens. At the same time, when moving the lens by a tilt or a swing, the IC is moved around the sensor plane. Composition is changed.
Is there a reason why Sinar made a digital rear standard carrier to place the digital back in a specific location, or is this not necessary?
Yes, of course, there is a reason and it is necessary, to have the tilt and swing axis being what they should be, assymetrical and IN the image(sensor) plane.
Thierry