Originally Posted by
sharktooth
In most monorail view cameras the rear tilt axis is in front of the film plane. if the tilt axis was through the film plane the rear standards will block the ability to insert a horizontal film holder when the back is tilted. You can get the front lens tilt axis to go roughly through the lens center since there's no obstruction issue like in the rear.
Eyeball some pictures of center tilt monorail cameras from the side view, and you'll see that the front lensboard probably cuts through the front tilt pivot axis. On the rear, however, the film plane will be well behind the rear tilt pivot axis. The further the film plane is behind the rear tilt axis, the greater the allowable tilt.
If the rear tilt axis goes through the film plane, then anything along that axis will not change position when the back is tilted. If the rear tilt axis is not along the film plane, then everything changes focus as you tilt. The amount of focus shift near the centerline of the film isn't that much with center tilts, but is a lot with base tilts.
The Sinar P camera introduced an ingenious way to use tilts. There are no uprights to block film holder insertion, and the tilt axis is moved to the lower section of the frame with a marked line on the ground glass. If you focus on something along that line, you can then tilt the back to focus on another point in the frame. This won't affect the focus of the point you focused on first. This basically achieves tilt focus in fewer steps.
The Horseman L system has both top and side access to install the film holder without blockage, so the tilt axis can go through the film plane. On the basic Horseman L you have a center tilt axis going through the film plane. On the more advanced Horseman you can also shift the axis tilt so it can be above or below the center axis, and do the same thing as you can do with the Sinar P/P2. The advantage of the horseman is that you can choose where you want the tilt axis to be. That's what sets it apart. You can't move the tilt axis on the Sinar P/P2 directly, but you can shift the standard up or down for focusing, and then shift it back down after focus is set. It's almost the same thing but an extra step.
Bookmarks