Understanding movements better to correct perspective.

[dikaiosune01]

I have a nagging that this has been asked before. I do apologize and ask that you bear with me. I freely acknowledge that my thread searching skills are not up to snuff; as I gave up after three variations of searches.

I've been shooting 4x5 for about 3 years now. However to this day, I don't fully understand how movements can correct perspective. I've done multiple wall tests and building tests; and usually after an hour of head scratching I give up without shooting a single shot because I couldn't get the result I was going for.

This was the exercise I was going for:
When shooting a building from ground level, the resulting image will look like a trapezoid, with the top tapered. This is a result of angling the camera upwards, shooting up at the building. My exercise is to straighten the building into a proper rectangle.
If there are lamp posts in the foreground or other buildings in various planes in front or behind the building, is it possible to straighten those secondary subjects as well?
Are the limitations of movements limited by the image circle? Movements? Or both? And I need to better choose my subject that are within the limitations of my equipment.

Thank you

Shen Hao 4x5 135mm and 180mm lenses with image circles large enough for 5x7

[Tin Can]

I am no expert, but it does seem to me that perspective control is limited to one plane. Yes that plane may be at any angle, but it is not elastic. As soon as you introduce another plane, focus and perspective change.

[Struan Gray]

If you keep both the back of the camera and the lens panel vertical, everything that is vertical on front of the camera (buildings, lamposts, signs etc) will end up parallel in the photo.

The classic way to show this is to take two photographs of the same scene. First, by tilting the camera up to include the top of the building. Second, by levelling the camera and using shift to move the image on the ground glass until you get the framing you want.

Most people start by shifting the lensboard up. When you run out of up-shift on the lensboard, some cameras allow you to shift the camera back down. When you've maxed out both of those, you can get even more shift by pointing the camera up a bit using the tripod head, and then returning the lensboard and camera back to vertical by tilting them on the rail/baseboard.

All that really matters is the relative position and orientation of the lensboard and the camera back. How you get there is up to you.

Somewhere you will run into the limits of your lens' coverage. Either you get a black horizon (common with most modern lenses) or you get a fuzzy image which cannot be sharpened by stopping down. In the latter case, it's a question of taste where the limit lies.

If you want to practice, it is easier to see the effects with a normal lens, since you avoid vignetting and the hot-spot which results if you use a wide angle lens onto a plain piece of ground glass. In fact, one of the little-appreciated joys of LF is that you can make a normal lens look like a wide angle by shifting to the edge of it's image circle.

Finally, since you're in Hong Kong, you can see the opposite effect too: go to a high building, or a lookout on the mid-levels and point your camera down at a group of tall buildings. Now you can see the tops splay outwards rather than inwards, which can be corrected by levelling the camera and shifting the lensboard down.

Note that you can force the image geometry so that, say, a set of windows on a high building remain rectangular. You cannot avoid the change in perspective as you move from the ground floor to the top of the building - you will see the ground floor windows and the rooms inside head-on, but on the upper floors you'll be looking at the underside of the lintel, and seeing the ceiling of the rooms inside.


There are similar effects for sideways shifts, but they are used less often because the perspective effects of lines of houses receding into the distance are expected by the viewer. They can be useful if you have a restricted viewpoint off to one side and want to show a head-on view, or if you just want to adjust the image geometry to give a particular impression. I have used it on occasion to give a more graphic, two-dimensional feel to a photograph of woodland by adjusting the vanishing points of the perspective.

[Ed Bray]

Whilst I am not a long term user of Large Format, I am pretty sure that only the Camera Back needs to be vertical to ensure that buildings remain with the correct perspective, whilst tilting of the Lens Standard only effects the plane of focus within the image.

[polyglot]

Think of it like this: the further away an item is from the camera, in a direction perpendicular to the film plane, the smaller it is. Simple perspective.

If you point the camera horizontally then every part of a vertical building wall will be the exact same distance from the film along that horizontal axis. Therefore the top and bottom parts of the building are rendered as equal sizes and it has no taper. You can test that trivially with any camera; no need for a view camera.

Now if you point the camera upwards, the top of the building will be further along that film-perpendicular axis than the bottom of the building, so the top of the building is rendered smaller. It's tapered.

You can think of perspective correction using shift as just cropping. Shoot a really wideangle shot of your building with a level camera, then crop out all the foreground dirt. That's what you're doing when you shift the lens up (or the film-back down) - you're recording just the top part of that larger image. The walls and streetlamps are all vertical because the film is vertical. That's all there is to it.

[rbultman]

Get the Kodak book Photography with Large-Format Cameras. There is a section on movements that is very will illustrated, better than the treatment in Adams' The Camara, IMO. That can be had used for less than $20. Even better is Simmons' Using the View Camera. Used copies of this book are insanely expensive (IMO).

To repeat others slightly:
1) Start with the bed horizontal and level and the front and rear standards vertical. Remove any swing, shift, or tilt.
2) Adjust the front rise until the subject is properly framed vertically. If you run out of rise or lens, meaning the corners are no longer sharp due to exceeding the movement allowed by the lens image circle, remove any front rise and tilt the camera bed until the subject is framed vertically. (If your camera also had rear rise/fall, you could adjust that until the image was properly frame vertically.)
3) If you tilted the image bed in order to vertically frame the subject, the verticals will no longer be parallel - this is your trapezoid problem, caused by the rear standard not being parallel to the building. Tilt the front and rear standards until they are vertical. This should correct the trapezoid problem and any focus issues. If the secondary vertical objects are also parallel, originally, to the vertical lines of the building, they should also be corrected now.

In short, try to keep the front and rear standards parallel to the plane you wish to keep in proper perspective.

[TheToadMen]

Maybe this will help:
http://en.wikipedia.org/wiki/View_camera#Movements

http://www.bhphotovideo.com/find/Pro...rgeformat2.jsp

http://www.largeformatphotography.in...-to-focus.html

http://www.toyoview.com/LargeFrmtTech/lgformat.html

http://paulturounetblog.files.wordpr...-movements.pdf

You can also make a search for: "The Scheimpflug Principle".

Bert from Holland
http://thetoadmen.blogspot.nl

[Bruce Watson]

When shooting a building from ground level, the resulting image will look like a trapezoid, with the top tapered. This is a result of angling the camera upwards, ...

Not exactly. It's the result of the film plane being tilted in relation to the plane of the building.

Start with the film plane being level and plumb. Use a level to be sure. This will in turn typically result in lots of front rise.

Often you'll have to tilt the camera base, then level and plumb the film plane, then use front rise -- all this to get enough front rise to capture the view you want. This in turn can introduce some vignetting as you get close to the edge of the lens' image circle. It can also introduce some vignetting from the bellows scrunching up -- something to watch for, especially with short lenses. Just sayin'.

All this said, some tapering down to the top of buildings is often desirable. If you nail the verticals so they are exactly parallel, they can often look unnatural in the final print. How much tapering is artist's decision of course.

Trees OTOH, tend to want to be exactly parallel in my experience, unless it's clear that you are really looking up at them, as in you are close to them. Probably has to do with the vast experience people have with how a forest actually looks. Similarly to how people don't tolerate distortion in human faces maybe.

[Struan Gray]

Whilst I am not a long term user of Large Format, I am pretty sure that only the Camera Back needs to be vertical to ensure that buildings remain with the correct perspective, whilst tilting of the Lens Standard only effects the plane of focus within the image.

True. I was going to add a bit about putting the plane of focus where you want it, but I'd already waffled on long enough :-)

Short form: keeping the lens board vertical usually puts the plane of focus where you expect it. Mostly relevant when using the tilt-the-rail and reset the standards to vertical trick.

[goodfood]

As you live in Hong Kong, the street is narrow and the buildings are very tall. The lens you in hand are 135mm and 180mm, those are standard lens for 4X5. You need a much wide angle lens such as 90mm, 75mm, or even 65mm with the coverage more than 4X5 film to have the movement. Also when you use those wide angle lens, you need a bag bellow on your camera. Check with your local camera club or dchome.net have some people using large format.