question regarding movements

[richard rackham]

Hi - I'm very new to large format (but have been a professional 35mm and digital photographer for 22:confused: years) and have an ageing Sinar F with 150mm f5.6 Schneider lens. I bought into (very cheaply) 5x4 because I wanted to make the most of the large DoF possiblities. Having attempted this today, I'm a little confused, as when I tilt the front down to try and get in focus, say - a rock in the foreground - everything else goes way out of focus - in front of and more so in the background. Is this actually how the image will be recorded or is it just the way the scene is appearing on the focus screen and in reality will have much more of the subject plane in focus. If that is the case, how do you accurately judge how far to tilt and where to make your main point of focus? Any help much appreciated. Cheers Richard

PS: I was viewing the image with the aperture wide open, but taking the shot stopped down to f32 most of the time.

[Bruce Watson]

...I'm a little confused, as when I tilt the front down to try and get in focus, say - a rock in the foreground - everything else goes way out of focus - in front of and more so in the background. Is this actually how the image will be recorded or is it just the way the scene is appearing on the focus screen and in reality will have much more of the subject plane in focus. If that is the case, how do you accurately judge how far to tilt and where to make your main point of focus? Any help much appreciated. Cheers Richard

The ground glass doesn't lie. It tells the exact and unvarnished truth. What you see is exactly what you get. This is one of the joys of LF!

There are some good techniques out there. There are some books that explain movements -- search this forum for discussions of the books. This website has some good articles available for free. Like this one on focusing. (http://www.largeformatphotography.info/how-to-focus.html) That's where I'd start.

Once you play around with it some you'll begin to see that DOF actually decreases with increased film format size, because of the concurrent increase in lens focal lengths. DOF is a function of focal length after all. What gives LF the appearance of increased DOF is the ability to manipulate the plane of exact focus -- something you can't do as easily with smaller format cameras.

So mastering movements is fairly important. And the best way to do that is to read and study, but then put the books down and go out and photograph. I'll take any excuse to get out there and make some photographs!

[climbabout]

Richard
Keep in mind that if you are tilting the front standard forward to gain near to far depth of field, you can only do this if you don't have a tall object in the near foreground. Front tilt will only work in 1 plane - the rest you need fstops to increase dof.

Lets assume the scene you talk about has no tall object in the near forground or middle distances. In your mind draw an imaginary line from the top of the rock in the foreground to the top of the tallest distant object.
With the front standard upright, focus about 1/4 to 1/3 of the way into the scene. Then while looking through the ground glass begin to tilt the front standard forward until near and far is in better focus. You may have to refocus and adjust the tilt a couple of times until near and far is as sharp as you can get it. Then stop down to get the rest in focus - this you can see on the ground glass. Most times you only need a few degrees of tilt - this of course depends on the focal length of the lens and the focusing distance. You can achive a similar result tilting the back toward you as well - although that will change the perspective slightly.
I use an old field camera, so that is my technique. I know there are sophisticated Sinar models that have controls that make this easier - but this is how most of us do it.
Tim

[Gordon Moat]

Just a simple aspect to add to this. When you have base tilt on a view camera, using tilt moves the lens forward or backwards when you tilt. So let's imagine you focused on that rock, then tilted using base tilt forward; the result is that your lens moved forward, and the image is now out of focus. So the next step would be moving the front standard, and the lens, backwards a bit, which should bring the image back in focus.

One thing I do when I plan on using bas tilt is to set-up the front standard slightly aft of the infinity stop. This gives me some room to move and not need to unclamp the front standard, which allows a usable focus range for any near or far objects.

As noted above, the ground glass tells you fairly well what you will get on the film. You can practice with the camera and ground glass without exposing film, and probably learn more than simply by reading books.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

[Emmanuel BIGLER]

Welcome back to the world of bellows cameras, Richard !
The required angles for front tilt in landscape are in fact much smaller than those required for photographing objects in the studio following the techniques described in the good old textbooks of the last century.

For example with the 150mm lens outdoors, if the lens is located at 1.5 metre above ground, the tilt angle required to bring the plane of sharp focus horizontal to the ground level is only 6 degrees.
And if you have a tall object in the field you should probably compromise and place the plane of sharpness somewhere in between ground level and some vertical plane where the tall objet is located ; for this you'll need only one half of the previous angle i.e. 3 degrees !
So tilting, yes, but just a bit for landscape use ;-)

[Nathan Potter]

Whether you use swing or tilt on the front or rear standard the principle is the same. If we use rear swing as an example imagine the following.

There will be an angle of swing such that a single plane in X and Y extending out from below the base of the camera will be in perfect focus from near to infinity with the lens wide open. The perfect focus will only be true for objects resting in that single plane. Any other objects that project out of that plane in the Z direction (vertical direction) will fall out of focus. In order to bring these Z axis objects into focus it is necessary to stop down the lens. The same is true when using tilt. As described above there are perspective considerations that add suttle effects as a function of rear vs front swing and tilt and whether such movements are on the optical axis or from the base of the camera.

Nate Potter, Austin TX.

[Mark Sloane]

Hi - I'm very new to large format (but have been a professional 35mm and digital photographer for 22:confused: years) and have an ageing Sinar F with 150mm f5.6 Schneider lens. I bought into (very cheaply) 5x4 because I wanted to make the most of the large DoF possiblities. Having attempted this today, I'm a little confused, as when I tilt the front down to try and get in focus, say - a rock in the foreground - everything else goes way out of focus - in front of and more so in the background. Is this actually how the image will be recorded or is it just the way the scene is appearing on the focus screen and in reality will have much more of the subject plane in focus. If that is the case, how do you accurately judge how far to tilt and where to make your main point of focus? Any help much appreciated. Cheers Richard

PS: I was viewing the image with the aperture wide open, but taking the shot stopped down to f32 most of the time.

Richard,

There is a ton of info out there to help. I too am a recent convert and one source I found very helpful was ytube.

I really struggled w/tilt and swing until I watched the video listed below. It's called: "Scheimpflug / Plane of focus" The instructor uses a cereal box for the demonstration so I watched the video and then set up the same scenario.

http://www.youtube.com/watch?v=gR4m70xr9mE

In addition, while on ytube, search for large format photography and you will be amazed at some of the video available.

[erie patsellis]

Richard, if you hunt down the manual for the F, there's a tilt calculator built in, takes all the guess work out (in theory, I always needed to tweak a hair).

erie

[richard rackham]

Many, many thanks for your responses, I think this is a brilliant forum. If you think there is anything an ex-press photographer (one who used to regularly uprate Ilford HP5 to 3200 to photograph floodlit football etc) can help with, please get in touch! Sincere thanks for your input, cheers Richard

[Capocheny]

Hi Richard,

Try going through the Sinar.ch website:

http://www.sinar.ch/site/index__gast-e-1830-52-1955.html

Lots of good info here.

Cheers

[Leonard Evens]

To understand tilts, you have to understand the geometry. With the standards parallel, there is one plane, also parallel to the standards, which is exactly in focus, but there is a whole region extending in either direction which is still well enough in focus so detail will appear sharp. That region is called the depth of field. It is bound by a near plane and a far plane, which are also parallel to the standards. The extent of the depth of field is dependent on where you focus and the f-stop. The more you stop down, the larger it will be.

When you tilt the lens, this geometry changes radically. Suppose you tilt downward. Then there is a line below the lens, called the hinge line. The exact plane of focus passes through it, as do an upper plane and a lower plane on either side of it, and the depth of field is the region between them. This region is often described as a wedge. As you focus by moving the rear standard, the whole wedge swings on this hinge line, which explains the terminology.

At any given distance from the lens, the vertical extents on both sides of the exact subject plane are equal. But because of the wedge shape, it is quite small close to the lens and gets larger as you move away from the lens. How large it is at any given distance depends on the aperture. The smaller the aperture the larger it is.

You can find graphical descriptions of this geometry at www.trenholm.org/hmmerk/#HR as well as at www.largeformat.info (which this forum is part of.)

But the picture you see at that website and most everywhere else ignores one important fact. You can't see the entire wedge, just that part of it visible on the ground glass in the frame. For example, you will never see the actual hinge line or even anything close to it on the ground glass.

Another point is that the comment that you can do everything just on the basis of what you see on the ground glass, while basically correct, is something of an oversimplification. The reason is that much of what you do is with the lens wide open for accuracy in focusing, but the picture will be taken topped down at a smaller to get the right depth of field. (See below.)

How do you use this in practice and how does it relate to what you see on the ground glass?

First, you should always try to see if you can accomplish what you want by stopping down. In that case there will be no limit vertically on what is in focus at any distance. But there are various reasons you can't stop down without limit. The most important one is that smaller apertures require longer exposure times, which you don't want if subject movement is an issue. In addition, loss of sharpness due to diffraction gets to be more of a problem as you stop down, and of course, there is a smallest aperture---usually f/45 or f/64 for 4 x 5 lenses---which is available.

In that case, you can try to bring things, usually close to camera, in focus by tilting. But that will only work if the region you need in focus is constrained fairly close to an appropriately chosen exact subject plane, particularly close to the lens.

So, how do you go about this in practice? Let me describe how it works in an example. Suppose you have a field of wild flowers starting near you and going into the distance. Suppose you don't have any trees or even bushes with significant vertical extent close to the camera but you do have trees in the middle distance and perhaps mountains in the distance. You want the flowers at ground level in focus as well as the trees and mountains. The bottom plane of the wedge would be at ground level and the hinge line would also be there. You can now imagine a plane starting at the hinge line and passing through the top of the trees or the mountains, whichever is higher. That is the top plane.

Now that you have the wedge firmly in mind, you need first to set an exact subject plane somewhere within it to choose the correct tilt angle. It doesn't matter too much which plane you choose, but in this example the ground with the flowers would seem appropriate. You then tilt to get everything in that plane in focus, doing this all wide open, without stopping down. I won't describe how to do this because it depends on where the tilt axis is and how you go about it. Details can be found at many other places including at www.largeformat.info. But when you are done, you have fixed the tilt angle, which you don't later change, except possibly for fine tuning the result.

But you don't necessarily use the exact subject plane you just used to set the tilt . Instead you focus so, as best you can tell, the exact subject plane splits the vertical extent of the wedge in half. (Remember that as you focus, the exact subject plane and the wedge about it will rotate about the hinge line.) In this example, you would refocus so the exact plane of focus passed halfway up the trees or the mountain, whichever were higher. When you do, the ground level with the flowers would most likely go out of focus.

Your next problem is to determine how much to stop down. There are several ways to do this. One way, which is completely visual is to stop down, observing what comes into focus as you do so. (You may also want to refocus to center the exact subject plane better.) When you have everything in focus, stop, and use that aperture to take your picture.

Unfortunately, this may not work because the image will get dimmer as you stop down. Most people can't see much of anything below f/22. There are several ways around this, but I will just describe one.. Stop down as far as you can and still see well enough. Pick some one point and look at what is in focus on the ground glass in the vertical plane at that distance. This will be a strip running across the ground glass. Measure the height of that strip, and then measure the height of what you would like it to be. Multiply the f-number you are using by the ratio to get the right f-number. For example, suppose everything you want in focus where the trees are lies in a window of height 30 mm. Suppose you have stopped down to f/16, and the window of what is in focus in only 15 mm high. 30/15 = 2, so use 2 X 16 = 32 as your f-number, i.e. stop down an additional two stops to f/32 to take the picture.

There is another method, which I use based on focus spread between high and low planes, but although it is simpler in many ways, I won't try to describe it here.

This process is a bit oversimplified. First, although in principle you first set the tilt angle and then leave it unchanged, in practice, you may want to fine tune it afterwards. Similarly for the position of the exact subject plane.

Finally, let me remark that the better you focus, the better your results. It is impossible to focus exactly, but you can improve your focusing reliability in various ways. The most obvious is by using a loupe, provided it is not so strong that you confuse surface features of the screen with the image. A 4 X loupe is probably strong enough.

A loupe will also allow you to see the dim image better, but there is one problem with that. A loupe lets you see things better, so it decreases the effective DOF as it would be seen in the print. That means you will end up choosing an aperture smaller than you really need. If that also leads to overly long exposure times, it can be a problem.

[sun of sand]

Play. Trial & Error is scientific.