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Thread: Large format movements: how much tilt?

  1. #1

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    Large format movements: how much tilt?

    I have just moved into 5x4 from medium format and have a question regarding the amount of tilt to be used when focusing in order to gain the maximum DOF. I spend most of my time photographing landscapes and seascapes and would like to get maximum sharpness from the nearest foreground to the background.

    Example: 5x4 camera with Rodenstock Grandigon 90mm lens. I am taking a photo of a rocky beach with plenty of small boulders to use as foreground interest starting from approx 6 feet from the camera, and the soaring cliffs further along the beach as my background.

    Question: Approx how much front tilt would I need to use to get to alter the focus plain and get sufficient DOF to capture the entire scene with sufficient sharpness? I would be normally shooting between f22 and f32.

    I appreciate that there are no exact answers to this question but would like to get a rough starting point from which to work from.

    Many thanks, Mark

  2. #2

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    Re: Large format movements: how much tilt?

    Hello Mark,


    I have just over a year experience with LF gears and love the 90mm for its coverage and depth of field. Depending what front tilt you have on your camera, base tilt is a bit more tedious to use than an axis tilt. With axis tilt I focused on the foreground then tilt the front standard on its axis to get the front to back sharpness. With 90mm not much tilt should be required to get the DOF unless you are focusing the foreground really close up. I sometime may use back movement to get the back ground sharp (only if necessary). With base tilt, which I seldom use nowaday, I can't comment on it apart that it is a lot more tedious to use. Other who are more experience could probably help you.

    Good on you for moving onto LF and where about are you located in Yorkshire. I was there for 3 years and could put you intouch with other LF users in Yorkshire.

    Regards

    Chong

  3. #3

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    Re: Large format movements: how much tilt?

    The hyperfocal distance for a 90 mm lens at f/22 is about 12 feet. If you focus at the hyperfocal distance, everything from half that distance to nfinity should be in focus. If you stop down further, you do even better, so you shouldn't need to tilt in order to get everything in focus. That calculation assumes a maximal allowable circle of confusion of 0.1 mm, a common value chosen for 4 x 5, which would apply for prints viewed from a normal distance for the size of the print. But if you expect people to get closer, then a smaller coc might be appropriate, which would increase the hyperfocal distance and result in the near subjects being slightly out of focus. In that case, you would want to use a tilt for a scene like what you describe.

    to understand how to tilt, you need to understand the geometry of the region of adequate focus. With the lens plane parallel to the film plane, this is bounded in front and in back by two planes also parallel to the film plane. But if you tilt the lens, these two bounding planes are no longer parallel and they meet in a line (usually) below the lens. The region of adequate DOF is the wedge shaped region between these two planes. The plane of exact focus is roughly in the middle of the region and how far it extends above and below that plane of exact focus is determined by the aperture. As you focus, the whole wedge swings on the above mentioned line, which is called the hinge line.

    The purpose of the tilt followed by focusing, is to put the plane of exact focus in the proper position. You can start by putting it on the beach, for example. To do this, you pick a near and far point and tilt so that both are in focus. To refine the tilt, focus on the far point and then note whether you have to increase or decrease the distance between the standards to bring the near point into focus. If you increase the distance, then increase the tilt; if you decrease the distance, then decrease the tilt.

    For a 90 mm lens, this should not be a very large tilt.

    After you have chosen the tilt, and hence the plance of exact focus., you adjust the focus and the position of the exact plane of focus so that there is adequate DOF above and below the plane of exact focus. There are ways to decide just how to do this, and they are described in detail elsewhere the the Large Format Photography web page.

  4. #4

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    Re: Large format movements: how much tilt?

    A rule of thumb : in landscape photography, if the camera is located at a height (probably on a tripod head) equal to ten times the focal length measured from ground, tilting the front or back by 6 degrees (~1/10 radian) will bring the ground plane sharp on the ground glass. e.g. with a 90mm lens you'll need 6 degrees if the camera is at 90 cm (3 feet) above ground level and only 3 degrees if the tripod is raised 6 feet (1,80m) high. A 150 mm at 5 feet (1,50m) will need 6 degrees as well. This is quite small actually.
    Sometimes you'll only need to tilt only half this value and play with DOF, if a distant elevated object also has to be sharp on film ; below 1 degree, a usual camera without any movements would do the same job except for possible shifts ...

    Some diagrams to illustrate (temporary ilnks valid for 3 weeks only)

    Last edited by Emmanuel BIGLER; 15-May-2006 at 10:07.

  5. #5

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    Re: Large format movements: how much tilt?

    The amount of necessary tilt is frequently just a degree or two. Many people starting out use too much and make things worse.

    Learn to judge through the gg. If you don't have one get one of the gg brigthteners - your screen will brighten by about two stops and make focussing much easier.

    steve simmons

  6. #6

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    Re: Large format movements: how much tilt?

    You can't go wrong with any of these replies. Don't let the technical side of LF get in the way of your visual--when in doubt use the gg and take Steve's advice--it is usually less than 5 degrees, especially with a 90mm. With a 90mm you may at times be better off using Hyperfoc. as another poster pointed out.

    That being said--this is what I do and it is simple and works great. Wheeler's rule of 60. Do a google search if you want to learn the math behind it--fairly complicated so my advice is just trust it--it works.

    You will need to carry a dollar store calculator and a small cloth or flexible tape measure that shows mm's.

    What to do: focus on your near object--mark your camera rail at this point; focus on the farthest object and measure the distance between the two in mm. Now measure the distance between these same two points on your ground glass and divide the numbers and then multiply by 60. This is your tilt angle.

    Example: focus on your forground rock--mark this point; focus on the distant mountain and measure the distance between the two points.....say 5mm. Next measure the distance between the rock and distant mountain on your ground glass (my gg has grids divided into 10mm).....say 65mm. Divide 5/65=0.077 ; then multiply this by 60=4.62 degrees of tilt.

    Sounds like a pain while reading but actually quite simple in the field after you have done it once or twice--it works.
    Last edited by Slade Zumhofe; 15-May-2006 at 21:42.

  7. #7

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    Re: Large format movements: how much tilt?

    Many people starting out use too much and make things worse.
    I agree with Steve S. since as soon as I started to use a view camera, I always wanted to tilt up to, say, 30 degrees, like I had seen in a famous advertisement for the Linhof Technika, where the famous and beloved technical camera is always shown in an improbable and horrifyng combination of extreme tilts ;-)

    The easiest movements that are actually a joy to use after so many years using a regular camera without movements are the shifts, mostly the vertical shifts. It is really pleasant to precisely frame by shifting the front or back and not by pointing the camera up or down !!

    I remember watching people playing with a view camera at the manufacturer's booth in a Paris exhibition two years ago ; people always wanted to tilt the front standard up and had trouble to focus ; this reminded me the famous reply by Groucho Marx in « a Night at the Opera » , the famous scene inside a jammed boat cabin, where Groucho says to the housemaid something like : " please, do come in, but you'll have to start with the ceiling "
    Last edited by Emmanuel BIGLER; 16-May-2006 at 01:15.

  8. #8
    Whatever David A. Goldfarb's Avatar
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    Re: Large format movements: how much tilt?

    I'll also agree with Steve Simmons and Emmanuel Bigler--for most landscapes like you describe, if tilt is useful (if you don't have something like a tall tree in the foreground and a mountain in the distance), then you usually need less than 5 degrees of front forward tilt.

    A landscape situation where you would need more would be a scene of a completely flat landscape with the camera level, but in that situation, the camera is often pointed down, since there wouldn't be an issue of keeping vertical objects square.

    Here's an example. I'm using a 75mm lens on 4x5". The camera is angled down maybe 30 degrees or so, and I used maybe 1-2 degrees front forward tilt to get the foreground and the rocks in the middle and far distance in focus--


  9. #9

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    Re: Large format movements: how much tilt?

    A quibble about Emmanuel's diagram 2:

    The pivot (hinge) line in that case would be on a vertical line dropped plumb from the lens. That would always be the case if the back is vertical. If the tilt were chosen so that the plane of exact focus is at ground level for some position of the standards, then the pivot (hinge) line would also be at ground level, about where he has shown the leftmost tripod foot.

    Another interesting fact is that at the hyperfocal distance from the lens, the vertical extent in adequate focus, above and below the exact plane of focus is roughly equal to the distance from the lens to the pivot (hinge) line. So in this example, with the camera about 5 feet above the ground, using a 90 mm lens at f/22, you would find that 12 feet from the lens (the hyperfocal distance), the DOF region would be about 10 feet and be centered on the plane of exact focus. This sounds like a lot of numbers, but once you understand the principle, it can become pretty intuitive. Look at the distance from the lens to the plane of exact focus, and project it out in space in your mind to the hyperfocal distance. Then imagine it expanding or contracting proportionately at other distances distances. If there is some vertical extent you want in the DOF region, focus so the plane of exact focus is centered in it and estimate if the range of DOF above and below encompasses the entire desired vertical extent. With some practice, this becomes second nature. It won't give you precise numbers, but you can often tell if you have any chance of the desired end.

    Of course, with moderate apertures such as f/11 or f/16, you will be able to see on the ground glass what is in focus after stopping down. But few of us can see much of anything when stopping down to f/22 or below. It is in those cases where the method described above is useful.

  10. #10

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    Re: Large format movements: how much tilt?

    Quote Originally Posted by Leonard Evens
    A quibble about Emmanuel's diagram 2:
    The pivot (hinge) line in that case would be on a vertical line dropped plumb from the lens. That would always be the case if the back is vertical....
    Oooops ! Yes ! One focal length ahead of the lens !!




    (the image link will be valid for 3 weeks, please contact me to get a copy)

    Quote Originally Posted by Leonard Evens
    you can often tell if you have any chance of the desired end
    What about this "Scheimpflug in the Corner" quiz ? ;-);-)

    For those who really want huge tilts !!

    Last edited by Emmanuel BIGLER; 16-May-2006 at 11:54.

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