Rise/shift the same as raising the camera or relying in lens geometry distortion?

[Vaughn]

It took me many years of using a view camera before I realized that pointing my camera up (or down) and making both standards vertical was the same as front rise (or fall). I was just using a different starting point in creating the image on the GG where pointing the camera up or down, or on the level, is an element of composition to be used. But a lot of this was driven by learning to photograph in the chaos under the redwoods. None of my images for years had horizon lines...

Camera pointed down, allowing the trees to slightly flare outwards not all the way corrected with back tilt (159mm lens on 8x10. pt/pd print). The camera lens is about 30 feet above the forest floor, camera on on top to two criss-crossed fallen redwoods. The Boys, Prairie Creek Redwoods State Park, CA.

 

[xkaes]

And if you don't get the lines "correct" when the picture was taken, you can always "correct" them under the enlarger.

 

[Vaughn]

And if you don't get the lines "correct" when the picture was taken, you can always "correct" them under the enlarger.

A little tougher to do with contact prints...

But one of the enjoyments of view cameras is the view on the ground glass. Depending on the circumstances, one often has the time to work with the image on the GG. One can see how the 3D world translates into 2D and can see the changes the various movements make in the image.

 

[grat]

Don't you mean "raising" the lens?

In the case of a tall building, that you're at the base of, sure. Of course, if you're in a tall building or hill, looking down at another structure, you might want to "drop" or "lower" the lens. The goal is still to alter the field of view so as to maintain parallel lines.

I used "shift" as a somewhat generic term for a lateral/vertical movement that keeps the lens and film plane parallel. Similarly, "tilt" covers both "tilt" and "swing", as to me, it's revolving the lens around an axis relative to the film plane.

I realize it's less precise, but it's preferable to "when raising/lowering/shifting right/shifting left, while maintaining a parallel relationship between the plane of sharp focus and the plane of the light sensitive medium contained within the light-tight box...". But of course, that's for the generic case-- for specific details, "I used 1cm of rise, 2cm of left shift, with a few degrees of forward tilt when taking this image", obviously the distinction makes more sense.

 

[Helge]

if you are raising the lens it allows you to reduce the amount of foreground in the frame and see more of the upper part of the image circle, while keeping the film plane parallel with the subject.

Watch this video, he uses two different focal lengths with rise, for the same effect of keeping parallel lines straight and reducing the foreground.

Ok this made it click for me.
The first shot was a very good example of how and why to use rise with a normal lens.
When shooting with other formats, my initial instinct would be to just move back a bit, or a lot, and/or use a tele lens, to get everything in frame and still keep the camera level.
But of course that is far from always possible. You change the composition (however slightly) and you don't always have the option of physically moving further back.
Here it is only a little bit of the building that is cut off at the top. And that is easily corrected.
I was imagining something more dramatic, which is of course also possible under other circumstances and with other focal lengths.

Helge,

A couple of things:

First, it confuses the issue by using the terms "tele" (for telephoto, I presume) to mean a long focal-length lens for a given format and "wide-angle" to mean a short focal-length lens for a given format. "Telephoto" is a lens design that allows longer focal lengths to focus at infinity with the lens physically less than its focal length from the film plane. On the other side, many short focal-length lenses for 35mm and medium formats are "retrofocus" lenses, a design that allows them to physically focus infinity on the film at a distance greater than their focal length. "Normal" lens designs focus at infinity when the center of the lens is roughly the lens' focal length from the film. All this to try to get you to use "short," "normal" (for the format), and "long" instead, just for clarity's sake.

Also, don't confuse the "distortion" introduced by short focal-length lenses with perspective control accomplished by positioning the camera back/film plane. Objects at the edges of the field of coverage with short focal-length lenses appear stretched out, and thus "distorted" due to the steep angle of the projection. Similarly, short focal lengths tend to render near objects larger than we expect in comparison to more distant objects due to the wide angle of view (this, when compared to the "normal" angle of view we get with our eyes makes images made with short focal lengths seem unreal). This has nothing to do with perspective changes that happen when the film plane is repositioned relative to the subject.

In the three images you post, you make one with the camera back/film plane/sensor parallel to the tower, one with the camera pointing up, causing the verticals to converge toward the top of the image and one with the camera pointing down, causing the verticals to converge toward the bottom of the image. This is exactly what happens when the position of the film plane/ground glass/etc. is changed relative to the subject. If you don't want convergence, the film plane must be parallel to the parallel lines in the subject.

The converging verticals toward the top of the image in your second image is what many try to avoid by using front rise on a view camera or special shift lens on smaller cameras. You may find it more "natural," but many of us don't. As you point out, the eye/brain system straightens the image out in our imagination; even when we look up at something, we somehow recognize the parallel lines. Rendering parallel vertical lines parallel on the film is a convention of architectural photography done with view cameras that has been around for years. Until recently, converging verticals in professional architectural photography were purposefully avoided.

As for the vanishing points: With the lens axis centered on the film plane, receding parallel lines will always come to a vanishing point in the center of the image. Converging horizontal and vertical lines will have their vanishing points on vertical and horizontal lines that intersect the center of the image (either within or outside of the image borders). By using rise/fall or shift, we change where the lens axis intersects the film. That point is no longer at the center of the image but displaced up, down or to one side. The positions of the vanishing points move together with the displacement.

Moving the entire camera while keeping the film parallel to parallel lines in the subject is not the same thing as using lens rise from a lower viewpoint to keep vertical lines parallel. In the first case, you are moving the viewpoint, in the latter, not. Let's say you have a six-story building. If you move the camera up to be at the height of the third floor, your viewpoint, i.e., the point in the scene that is on the lens axis of view, will be on the third floor and in the center of the image. That will be the "straight-on" point in the image and the windows and doorways at the edges of the image will be all viewed from an angle.

If you keep the camera position low, say in the middle of the ground floor, keeping the film plane parallel to vertical lines in the subject, and then use rise to get the top of the building in the image (thus keeping parallel vertical lines from converging), the point in the image that is on the lens' axis of view will be on the ground floor, which ends up being at the bottom of the image projected on the film. Everything above that point will be viewed from an angle. This effect is very different from moving the entire camera up.

You say that focal length is "very closely tied to angle of view..." Well, for any given format, the lens' focal length determines the angle of view. The angle of view for a particular focal length and film format never changes. It doesn't matter if the lens has a large or small image circle, etc. The image size (i.e., magnification) is a function of the focal length.

Note also that one can use front rise on a view camera with any focal-length lens one chooses, long, short or "normal." I often used lots of rise with a 210mm lens on 4x5 for architectural work. This is a slightly longer than normal focal length for 4x5, so the stretching of off-axis objects that happens with very short focal lengths doesn't happen at all (that's because the lens' angle of view is similar to that of our eye). In your photos, there's lots of stretching off-axis because the lens you used was a very short focal length for the format and the angle of view is much wider than that of your eye. All that stretching "distortion" is due to the wider angle of view.

Finally, to answer your question about how correcting converging verticals is done with a view camera. It's really fairly elementary. Step one, if you want the parallel lines in the subject to be parallel on the film, the film plane needs to be parallel to them. In practice in architectural photography, this means the camera back/film plane needs to be level and plumb (because we assume that the building we are photographing was constructed level and plumb). Then, the image is framed by moving the lens about with rise and/or shift. This moves the lens axis relative to the image and moves the point of view around in the image, but it keeps the parallel lines parallel. That's really all there is to it. Of course, we need a lens with a large enough image circle and a camera with enough movement to do this. Sometimes it's not possible to get what we want.

All for now

Doremus

Doremus, your long and well written post was not in vain. I read it and enjoyed it, as I'm sure many others will do, but it just didn't really give an example that made me understand.

Yessssss

As in the edit, it's a macro lens. Didn't think of that, even if I have Minolta swing bellows.

 

[AgX]

Don't you mean "raising" the lens?

I understand "shift" as a superior term, subsuming both, lateral as vertical shift. Think of "tilt and shift" lenses.

When the terms "rise" and "fall" are used, then "shift" likely refers just to a lateral shift. It all depends on context.
Likely here too.

 

[xkaes]

In many instances using the term "shift" doesn't make a difference as to direction, but in this particular case of a vertical subject, it makes a difference. Here, "rise" is what needs to be clear -- not just any old "shift".

 

[Sirius Glass]

Raise is up.
Shift is right or left.
There is no need to make it harder by mixing those too or throwing in tilt is is a front lens rotation and something completely different.

 

[AgX]

You missed my, point. In many camera specifications "shift" is used as superior term and then listed for the 4 directions of it, some "shift and tilt lenses" are rotatable, thus their shift can be directed any way. Some (most?) languages do not even know the terms "rise" and "fall". And this seems the important issue, you are unaware of.
And in this context also from an engineer's point of view "shift" is the superior term.

 

[xkaes]

"Superior" is perhaps not the most superior adjective to use here.

 

[RalphLambrecht]

Yes.

You're simply good to different part of the projected image.

 

[Vaughn]

All much of a muchness, as my exwife use to say...

As long as the person one is communicating with understands what one means.

 

[abruzzi]

The common terminology obviously long predates me, but in my head I really divide it into two movements--parallel movements and angular movements, then I further subdivide angular movements into front and rear angular movements. The helps my brain compartmentalize them, but I know I need to translate into the common usage when talking to others about it, since my terminology isn't known beyond me, but my thought goes like this:

- parallel movements just allow you to select what part of the image circle you are cropping to. front and rear parallel movements are fully "transitive" (this is really a misuse of this mathmatecal term, but it helps me) in that movement X on the front is identical to movement -X on the rear.

- front angular movements place the plane of focus as well as the zone of apparent focus (i.e. the depth of field) at an oblique angle to the film plane.

- rear angular movement also allow you to place the plane of focus at an oblique angle but also changes the geometry of the image, like converting a rectangle to a trapezoid. Because of the impact on the geometry angular movements are not "transitive".

I understand that in the mechanics of most large format cameras the hardware that enables rise/fall is different from the hardware that enables left/right shift and is probably why the two movements got separate names, but as AgX points out, on 35mm perspective correction lenses, they are usually implemented as a single mechanism--a rail that lets you off-center the lens by a certain amount, and a ring that lets you angle the the "shift" in any direction. To me shift, rise and fall are all the same function and it helps (me) to understand them that way.

 

[Doremus Scudder]

@abruzzi,

I think the term you're looking for is rotationally (or radially) symmetrical. In the case of rise/fall vs. shift, the effect is the same, just displaced by 90°, so the movements are rotationally symmetrical.

The same with tilts vs. swings; just displaced 90° and therefore also rotationally symmetrical.

Rise, fall and lateral shift are a family. Front tilts and swings are a family. Rear tilts and swings are a family. Front and rear tilts and swings have different effects on the image projection, so can't be in the same family, even though they work the same

Base tilts need more iterative refocusing than axis tilts, but the effect is exactly the same. Swings are almost always axis swings, even on bare-bones field cameras. Asymmetrical tilts and swings are just a refinement of axis tilts and swings; the axes are just offset. Just different mechanical solutions to the same problem

Really, all the mechanics and methods of moving things around on a view camera are just ways to get the lens and the film plane into different spatial relationships. Sometimes I figure out what that relationship is going to have to be to get the effect I want before I decide how to go about accomplishing that. There's more than one way to get effective rise, for example.

Image perspective is controlled by viewpoint (camera position) and the angular position of the film (camera back) in relation to the subject. To get a specific angular positioning of the back relative to the subject, one can either set up and then tilt/swing the back to get it where you want it or just set up with the back in the desired orientation and then tilt/swing/shift to get the lens in the right position. The end result is the same.

Back to our original topic: In order to keep vertical parallel lines from converging, the camera back has to be set up parallel to them. Set up your camera with the back parallel to start with and then use rise to frame the image or set up with the camera pointing up to frame the image and then tilt back (and lens to retain focus) parallel to the subject lines. Either way ends up with the same spatial relationship between back to subject and lens to film.

Want to do the same with horizontal parallel lines? Well the movements are rotationally symmetrical so...

Best,

Doremus

 

[AgX]

Abruzzi, I am totally with you. I rather see movements by their kind and by their effect, less by their name. This also may be added by that I learned about this all first without the English terms. Moreover I realized that terms vary between languages.

The thing is to try to understand the basic effects. And then transfer them to real existing cameras. And here seemingly the forest easily gets hidden by the trees.
Think of the remark by some other fellow above that it took him very long time to understand that "direct rise" and indirect rise" are basically the same. (In this case the application of one or the other may be due to movement limitations at the camera, or the strive for better stability or to avoid yaw, etc.)

 

[Jim Andrada]

I think this can be really simplified. To start, yes, the image circle of the lens must be significantly larger than the film dimension.

What does this mean???

It means that the actual image projected by the lens onto the film plane (actually, probably mostly hitting the bellows...) is a lot bigger than what you see on your ground glass. Raising the lens (not the camera) raises the part of the image that you couldn't see because it used to be off the bottom of the ground glass up to where you can see it. And since the image is inverted, what you get is to bring more of the lower part of the larger-than-groundglass-size image (the upper part of the scene) onto the groundglass.

And it's a lot different than raising the camera because you've effectively increased the angle of elevation just as if you had pointed the whole camera up - with the advantage that by keeping the camera back parallel with the object, you won't have any "keystoning" effect where parallel vertical lines become slanted.

If you're taking a photo of a distant mountain. the difference is probably insignificant. If you're photographing a tall building close to you it's VERY significant.

 

[warden]

I've learned a lot in this thread. Thanks everybody.

 

[grat]

To start, yes, the image circle of the lens must be significantly larger than the film dimension.

Not necessarily. Depending on distance and field of view, 1mm of movement at the film plane can result in many meters of shift at the plane of focus. For 4x5, a 200mm image circle will cover nearly all movements your camera is capable of, and the "base" image circle for 4x5 is ~162mm.

 

[AgX]

Grat, good point. Actually plain simple. But as I said : trees and the forest...

 

[xkaes]

Not necessarily. Depending on distance and field of view, 1mm of movement at the film plane can result in many meters of shift at the plane of focus. For 4x5, a 200mm image circle will cover nearly all movements your camera is capable of, and the "base" image circle for 4x5 is ~162mm.

I'd call a 200mm IC "significantly larger" than 4x5 film. But the IC does NOT necessarily have to be "significantly larger" than 4x5 film. I have two lenses that are "barely" larger than 4x5 film. That's a limitation for shifts & rise/fall -- not so much for swings & tilts. And I have lots of macro lenses with image circles much smaller than 4x5 film -- when focused at infinity, which is NEVER. How bout 12.5mm?

 

[grat]

I'd call a 200mm IC "significantly larger" than 4x5 film. But the IC does NOT necessarily have to be "significantly larger" than 4x5 film. I have two lenses that are "barely" larger than 4x5 film. That's a limitation for shifts & rise/fall -- not so much for swings & tilts. And I have lots of macro lenses with image circles much smaller than 4x5 film -- when focused at infinity, which is NEVER. How bout 12.5mm?

200mm is +19mm in all four directions. That's less than an inch in any direction.

How many buildings do you photograph with those macro lenses?

 

[xkaes]

Fujinon, alone, made around a dozen NON-macro large format 4x5" lenses with image circles smaller than that -- mostly wide angle, of course -- so they thought it worthwhile. For buildings I'm usually using a wide lens, and most of the wide lenses I have do not have humongous image circles. You can label it whatever you want, but a lot of photographers have image circles way larger than they need -- and they don't even realize the problems that can cause.
The issue is how much IC do you need, and that depends on the subject. For many, like portraiture and close-ups/macro, you don't need much at all.

 

[reddesert]

Books on large format photography such as Simmons's "Using the View Camera" or Stroebel's "View Camera Techniques" typically have an entire chapter devoted to the effects of front and back movements, with illustrations. In both of these books, the illustrations include photos of a set of children's wood cubes with letters, so that you get a sense of how the movements can shift both perspective and focus.

When you have questions about the effect of movements, I recommend looking at a photo-heavy medium such as one of these books. Words can only do so much. I don't know of a website that has as comprehensive a set of illustrations.

 

[grat]

The issue is how much IC do you need, and that depends on the subject. For many, like portraiture and close-ups/macro, you don't need much at all.

True. I even have a Fuji 105mm f/5.6 with a rather small circle. But this thread is about shift and other movements.

 

[xkaes]

True. I even have a Fuji 105mm f/5.6 with a rather small circle. But this thread is about shift and other movements.

Shift and Rise/Fall all depend on "how much IC do you need -- and that depends on the subject".