Understanding rear tilt/shift

[Philippe Gauthier]

I currently have two old view cameras. One is a 4x5 with lots of front movements - rise, shift, tilt, swing. While "Scheimpflug" remains a difficult spelling exercise and the math/geometry behind me continues to give me headaches (I'm seriously math challenged...) with intuition, practice, observation and some reading, I came to a practical understanding of front tilt and swing and of the angles needed.

My second camera, however, is an early 20th century 8x10 that does not feature as many movements. I'm essentially limited to front rise and rear tilt/swing. And that rear tilt/swing is precisely what I cannot figure out - there must be something counter intuitive about them, as I never seem to find a solution that really works.

Could you prime me about the use of these reat movements? Not in math/geometry terms that will only confuse me, but in terms of general strategies that will allow me to change the plane of focus as I want. I'm quite ready to fiddle a bit to find the right angle, but right now I don't even think I'm doing the right things with these nice brass gears.

[James E Galvin]

The back movements do the same as the front, except in mirror image. If you need to tilt the front forward, then tilt the back backward. The difference is that back motions also change geometry, they make verticals and horizontals not converge, (or converge more if thats what you want.) For landscapes, for instance, one needs to bring the foreground into focus: tilt the front forward or the back backward, does the same, except the back tilt will enlarge the foreground some, for the small motions required, not much. I focus on the middle of the glass, then look at the top and tilt (usually the back, its easier to reach) for focus at the top. Then back to the center, back and forth a couple of times. Then look at the rest of the glass. If something is out of focus, then split the difference with focus and tilt. But you already got most of that, just go the opposite way you did with the front. If, however, you are doing architecture, then you need both movements, back to correct geometry, front to set the focal plane. The shifts again do the opposite front to back, with the exception that front shift moves the lens, changing point of view a bit, important for closeups.

[Michael Veit]

Philip, here's an exercise that might help: set up one of your modern cameras with normal front tilt as you'd use to get an extreme near-far focus landscape shot. Now tilt the entire camera up so that the lens is again perpendicular to the horizon ...and note what happens to the BACK of the camera and the tilt IT develops. Set up your older back-tilt camera the same way and shift the entire camera forward and you've effectively recovered front tilt capability.

[Philippe Gauthier]

Thanks, Jim, that's exactly what I was hoping for. I'll read this again a few times and try to practice it this week end. Now, a small gift for your help - a rare sight on this site, a picture!. Tea toned cyanotype, contact printed from a 8x10 negative. There were no movements needed on this one.

[Philippe Gauthier]

Michael. I just played with my 4x5, trying to figure out this thing... Now, if my lens is front tilted by say, 10 degrees, making it vertical again while holding the back will give a 10 degree angle to the camera rail and the back will appear vertical (but with a 80 degree angle to the rail).

Now, if I understand this well, you mean that if, instead of keeping the 8x10 camera in a level, "zero" setup, I tilt the entire camera forward while keeping the rear standard vertical, I will effectively get the same effect on the plane of focus as tilting the front standard - with the exception that your solution creates some issues with straight vertical lines, but there's no way out of this with rear moves. Is that right?

Now, what's the practical difference between tilting the entire camera and only tilting the lens? Intuitively, I'd guess that I'll get more near, low lying elements (flowers, grass, rocks, etc) in the frame while the other method will be more efficient for subjects at the same level or further away... Is that right and are there other considerations I'm not thinking about?

[David A. Goldfarb]

I find it helps to think of the front and back of the camera as planes in space without thinking too hard about what's in between or how it got that way.

On your camera with front rise/fall and rear swing and tilt, say you want the effect of front tilt to adjust the plane of focus for a near/far composition. Tilt the back until the plane of focus is where you want it; tilt the camera so the back is plumb (reducing the exaggerated near/far effect, if that is your taste); and raise the lens to recompose, and everything should be about right.

Say you're using a small format camera with a TS lens or a lightweight view camera with no rear movements and you want the equivalent of rear movements. Tilt the camera until the objects in the frame are the shape you want them to be; recompose using front rise/fall/shift; and apply front tilt/swing to correct focus.

[Erik Sherman]

>> Now, what's the practical difference between tilting the entire camera and only tilting the lens? <<

The problem is that with the setup you described, front rise only and rear tilt/swing, you cannot just tilt the lens. However, by tilting the whole camera and then compensating to whatever degree with a combination of rear tilt and front rise, you are effectively creating an equivalent relation between the film and lens planes. It's similar to how you can effectively create rear rise if you don't have it but do have front and rear tilt - you tip the bed of the camera, then tilt the front and back so that they are again vertical and the rear standard is now higher than the front.

More generally, tilting or swinging the entire camera is like tilting or swinging any kind of camera, because you end up forcing the vertical or horizontal lines to apparently converge. Moving the rear standard independently lets you put the film plane parallel to the image plane, and that preserves the horizontal and vertical relationships. By moving the front standard independently, you can move the lens plane parallel with the image plane, putting everything in the image plane in focus.

>> Now, what's the practical difference between tilting the entire camera and only tilting the lens? Intuitively, I'd guess that I'll get more near, low lying elements (flowers, grass, rocks, etc) in the frame while the other method will be more efficient for subjects at the same level or further away. <<

If you tip the lens, you actually change the plane of focus in the image, and you don't end up getting more low lying elements. To get more of those, you use rise and fall. Front rise and fall will work, but will also change the height relationships of objects to some degree. (It's like climbing on a ladder - you can see higher up, but the relationships of objects change.) Rear rise and fall will, respectively, give you more of the low lying or the high lying (flying?) elements. It's reversed from what you might expect because the lens inverts the image onto the film plane. The advantage of rear rise/fall is that it doesn't change the height relationships of objects in the image.