Scheimpflug and another question

[Valerio Trigari]

Hello everyone,

I've been playing with my view camera for a few weeks now and I think I got the basic concepts right, which is all good.

However, when it comes to tilts and swings connected to the Scheimpflug principle, I still find it difficult to get it right. I'm doing a lot of guess work to get the right adjustment, and sometimes the result is not what I want or expect. Do you have any suggestion or trick that would make my life easier? That would be much appreciated!

The other question is: does everyone take about half an hour - or so - to take a shot, or is it only me being slow as a newbie? I don't mind taking my time, but I do wonder if I'm a bit slow...

Ciao

[Joanna Carter]

… when it comes to tilts and swings connected to the Scheimpflug principle, I still find it difficult to get it right. I'm doing a lot of guess work to get the right adjustment, and sometimes the result is not what I want or expect. Do you have any suggestion or trick that would make my life easier? That would be much appreciated!

Hi Valerio. The first thing I would venture to suggest is that you may be trying to put too much tilt on the front standard to achieve what you want but it would help us to help you if you could give us an example of the kind of scene you are trying to focus, preferably could you post a digi-snap of the scene?

The other question is: does everyone take about half an hour - or so - to take a shot, or is it only me being slow as a newbie? I don't mind taking my time, but I do wonder if I'm a bit slow...

Half an hour is not too slow; in fact, it might be considered quite quick for some scenes

This first shot took me around two and a half hours to set up:



… whereas this next shot took less than five minutes:



It really does depend on what you are photographing, not just your length of experience

[IanG]

Valerio, when I teach using swings and tilts I get people to practice with extremes, it's a remarkably fast way to learn. What you then realise is how quick it is to set up, there's no reason why someone can't setup an LF camera in close to the same time as a tripod mounted 35mm or 120 camera.

How long you wait for the right moment to press the shutter is another matter. I've had to get a 10x8 camer setup in under 2 minutes, that included positioning the tripod, meter readings etc and it's just logic and I can't say just experience with the camera as I'd not been shooting 10x8 very long at the time.

The important part is get to know your equipment, practice tilts and swings on extremes then you realise real life subjects just need a slight touch, you can't afford half an hour, the train will have left, the rain started the sun gone, the model got bored and gone home.

Ian

[Susie Frith]

Hi Valerio,

As Joanna said, you may well be putting on too much tilt: it is very sensitive. Certainly, with the Kardan, it is very difficult to put a small amount of front tilt on, as the ball detent wants to snap the lens panel back to zero. On mine the 'baggy' bit of the bellows also fouls the lens support.

One way to see how much, or little, you need is to set up a scene with a receeding foreground. With everything set to zero, point the camera down to include the foreground in the view. Then, tilt the film plane back to vertical by loosening the rods on the rear standard. This should give you the approximate tilt. Also, by using the rear adjustments, you won't need a large image circle from the lens. Remember, the plane of focus, the lens panel plane and the film plane need to meet on a common line for it to be exact. In practice, like everything else, it will usually be a compromise.

Also, remember, that if you have more than two principal focus planes, at right angles to each other, adjustments won't really help. For instance, if you are photographing the inside of a church, you'll have five planes of focus: the far wall, the floor, the ceiling, and the walls to either side of you. In this case all you can do is stop the lens down.

Susie

[Neil Barnes]

At the risk of heresy - I can probably count on one hand the times I've ever chosen to use anything more than shifts to compose an image. There's a reason the vast majority of cameras in the world keep the lens parallel to the film...

Let me give an example: Scheimpflug requires that the plane of the image, the subject (focal plane), and the lens all meet at a common point. The extreme case is perhaps when you are trying to photograph a floor and have that as the focal plane. Let's say you have the camera on a tripod, mounted (for ease of numbers) two metres above the floor and normal to it, so the film plane is vertical.

The lens therefore must be tilted forwards so that its axis meets the floor directly under the camera. Assume - again, for the sake of the argument - a 150mm or so lens.

You're looking at a triangle with one side of 2000mm and one side of 150mm. Trigonometry tells us that the angle of the lens is arctan 150/2000 = 4.3 degrees - looked at another way, if the lensboard is 200mm and pivoted in the middle, it would have to move about 7mm at the edge.

Neil

[Nigels]

My thoughts on Scheimphlug after 10 years of shooting LF are this. Scheimphlug found a scientific and technical way of describing a phenomenon that is utilised in large format photography. It is enough for me to understand the general adjustments to camera movements to affect the focusing of my camera in the desired way. Beyond that there is no need for me to know the science or technical details involved. So I check the ground glass and don't get bogged down in the tech stuff.
As for the time taken on a photo, it varies considerably. In static conditions the fastest would be about 10 minutes. As for the longest, a couple of years. I have set up dor a picture and conditions never happened so I abandoned. On returning a couple of years later I got the conditions and the shot.

[dave_whatever]

My thoughts on Scheimphlug after 10 years of shooting LF are this. Scheimphlug found a scientific and technical way of describing a phenomenon that is utilised in large format photography. It is enough for me to understand the general adjustments to camera movements to affect the focusing of my camera in the desired way. Beyond that there is no need for me to know the science or technical details involved. So I check the ground glass and don't get bogged down in the tech stuff.

I'd second those sentiments.

one thing I would add is that having some kind of knob-mounted DOF scale is tremdously helpful for me in determining which aperture to use once you've appled tilts (see about three quarters of the way down this page).

Its takes the guesswork out of it, and as I found during the first few months of using a LF camera, I am crap at guesswork.

[Valerio Trigari]

Thank you very much to evertyone for replying. It's probably the hundredth you get about this subject and I hope I didn't annoy anyone!

Having a degree in a science subject and working with maths as part of my job, I understand all the technical aspectes behind the Scheimpflug principle and this helps me in understanding why things work (or don't).

I think the main error was to apply too much tilt or swing, as Joanna and others suggested. The second mistake was, in my opinion, to use the wrong focal length for the type of picture I was trying to take. At the moment I only have a 150mm lens, so I have to do with that only.

I'll see if I can scan a few example of what I did, so that you can have a better idea. None of the pictures I took, bar one or two, had any pretence of art. They were studies on how to use my view camera. I want to learn the craft first and then do art. I daresay the other way round is nigh to impossible!

Cheerio

[Joanna Carter]

Thank you very much to evertyone for replying. It's probably the hundredth you get about this subject and I hope I didn't annoy anyone!

No matter how many times people ask, apparently, the same questions, there's always differences in the way the questions are asked and, sometimes, that different take is just what someone else needed to understand. So don't worry

Having a degree in a science subject and working with maths as part of my job, I understand all the technical aspectes behind the Scheimpflug principle and this helps me in understanding why things work (or don't).

Actually, too much technical knowledge is often more of a hindrance than a help

At the moment I only have a 150mm lens, so I have to do with that only.

Some people only ever use one lens.

I must admit I learnt more about movements by simply taking a lot of time playing with them, trying out different movements on different scenes, than I ever did trying to work out the maths.

Is there anyone on the forums, in the same area, that you could link up with for a day learning?

[Charles Twist]

Hello Valerio,
As you surmise, Scheimpflug has been covered a couple times. Since you have a more mathematics-science bent, you might get something from this thread.

Actually, too much technical knowledge is often more of a hindrance than a help

What a load of tosh! That's entirely a personal opinion. My own wanderings through the Scheimpflug and Carpentier rules using the Merklinger website have given me very valuable insights and helped to crack a focussing problem that had been hampering me for a while (see final post in link above).
Of late, I have noticed a few people on the forum discounting the value of movements. I think they're able to create the composition, and some, like this one, need a lot of movement:

Rolls.jpg (65.91 KiB) Viewed 9399 times

The back was swung by about 40 degrees if I recall - I had to swing the back rather than the front to stay within the image circle of the old triplet lens (f=187mm). The reason for the large swing was that I was little more than 16" from the Spirit while the windscreen was several feet away (all recollections). So a combination of close-up and not so close-up.
IMO you have to think through why you need particular movements and then do what you have to do.
Keep experimenting. It's healthy.
Regards,
Charles

[TimH]

Covering weddings now too eh mr Twist - Seriously tho - good example. Not achievable without significant movements ! Even easier to do with asymmetric movements too - ducks the incoming ha ha


regards Tim

[dave_whatever]

Even easier to do with asymmetric movements too - ducks the incoming ha ha

[JARRING CHORD]

[Joanna Carter]

Actually, too much technical knowledge is often more of a hindrance than a help

What a load of tosh! That's entirely a personal opinion. My own wanderings through the Scheimpflug and Carpentier rules using the Merklinger website have given me very valuable insights and helped to crack a focussing problem that had been hampering me for a while

OK, I think I might have used the wrong words there

What I was trying to say is that some people can get into working through the maths of Scheimpflug to the point where they forget that, "what you see on the ground glass is what you get on the film". Knowing the maths can sometimes inhibit people from "twisting the camera" because the numbers don't add up.

Take my pet "theory" of micro-tilt; some tell me that it can't work, the numbers don't add up; but I have found that, in reality, it is a very useful technique, which I used to good effect on the second of my example photographs in this thread.

Nonetheless, my micro-tilt theory is based on the numbers in Merklinger's articles. So, although it was my technical knowledge that inspired my use of micro-tilt, I certainly don't use any kind of calculation to make the image, it seems to be more a black art of intuition and guesswork to place the plane of sharp focus in an appropriate position, which even I can't really explain without showing someone on the GG.

IMO you have to think through why you need particular movements and then do what you have to do.
Keep experimenting. It's healthy

Indeed, sort of what I intended to say

… Even easier to do with asymmetric movements too

reaching for fly swatter

ducks the incoming ha ha

Drat! where d'he go?

[JARRING CHORD]

Ah yes, the comfy chair

[Valerio Trigari]

I don't want to be doing too much maths while composing my picture, but at the same time I need to understand the physics behind the concept. If the physics doesn't make sense, then I find it very difficult to apply things. I'm a scientist at heart, so if things don't add up, I don't believe they will work...

In my tests I did a lot of guess work in deciding the appropriate tilt or swing angle, in order to get the film, lend and object planes meeting at the Scheimpflung point. However in a few instances I could not get the thing right, even stopping down to f/45. By this I mean, I got the near and far point on focus, but everything else wasn't. This picture was taken with no adjustments at f/45:



While this was take with setting the rear standard to vertical and swinging the lens board, again at f/45.



As you can see, in the second one I wasn't able to obtain maximum sharpness all over. I do remember I had to swing the lens quite a lot, but that was the only way to get the front and back of the sawing machine on focus. Any suggestions? I still think that if I used a longer focal length I would have required less adjustemns, though the depth of field would have reduced accordingly. Maybe I'm wrong though.

I do agree with Charles that the best way to get things right is experiment.

[dave_whatever]

If you swung a lot in that last shot, and the subject is fairly close to the camera, then even at f/45 you won't have had a very deep wedge of focus either side of your flane of focus. That par for the course. The more your swing or tilt, the narrower the wedge. You might have got that shot in focus by under tilting a little bit then stopping down? In general, you're better undertilting rather than overtilting.