Originally posted by lbenac So a vertical shift at an angle of let say 30 degree from vertical would be to correct the vertical perspective only and slightly "move" the point of view to the side as you describe?
You can't correct convergence/divergence with your 6x7 by aiming it up or down from level. You only make things worse. 30° from vertical would be 60° from horizontal (level - that's a lot)
Even a 30° tilt up from level could cause a lot of distortion with a 75mm focal length for a tall building. A shift-lens really doesn't "correct geometry", per se. What it allows you to do is keep the camera level for good geometry and move the scene around from the shifting for a more desirable composition, I'd say.
What I was implying by saying you could tilt the camera a little is that if you had to aim a non-shift lens up say 30° to bring in a building for where you were standing that with the shift lens at the same location you'd could get away with tilting the camera a lot less producing just a little line convergence in your shot that could be easily corrected with software. When you correct it with software, you end up having to corp the picture. And that can be a big crop depending on how much you had to correct. If you didn't leave enough room for the crop while taking the picture, you might not get away with a full software correction at all.
Quote: The horizontal perspective or geometry - as a result of not been exactly parallel to a building could only be corrected by a tilt of the film plane (large format) or maybe also by a tilt of the front plane (tilt lens)?
Cheers,
Luc
No, not in this case if the camera is level. You'd need a rotation of the film plane to get it parallel to the subject. If the camera was not level then, yes, a tilt and rotation would be needed to get the film plane parallel to the subject's plane.
Front tilt of the lens affects where the lens is aimed and the plane of focus. It doesn't do anything for altering geometry by itself.