I've been thinking about different sources of error when using a view camera.
The first question that came to mind is how accurately one can level the camera and make sure the standards are as close to parallel as possible. Presumably, one can never get it perfectly right, but it seems reasonable that small errors won't make any significant difference in the angle the subject plane makes with the vertical. But some rough calculations seem to indicate that is not quite true.
I use levels for checking parallelism, so I did some measurement with my carpenter's level., which is about 600 mm long. The amount one end can rise above the other with the bubble still between the two lines seems to be about 2-4 mm. That would mean an angle between 1/5 to 1/3 degree. Say the angle between the two standards is 1/4 degree. With a 150 mm lens, that would mean the hinge distance would be about 34 meters. That seems so large it might be considered to effectively infinite. But suppose you focused at 10 meters, which is pretty close to the hyperfocal distance for such a lens at f/22. The angle by which the subject plane would depart from the vertical would be about 16 degrees, which seems pretty far from its being perfectly vertical.
I'm not sure just what that means. Presumably, in terms of what would be caught in the frame in focus, you couldn't really distinguish a 16 degree departure from the vertical from a zero degree departure. But it still seems paradoxical.
Any comments?
Also, how accurately do you think you can level your camera and how close to parallel can you make the standards?
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