Correction of perspective

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Any information on correcting the perspective on LF photography

-- pancho pistolas (esponjorge@hotmail.com), July 21, 2001

Answers

Are you sure that you want to change perspective?

Perspective changes with camera position. It is changed by moving the entire camera up/down/left or right.

-- Bob Salomon (bobsalomon@mindspring.com), July 21, 2001.


Some basics at:

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

-- Paul Schilliger (pschilliger@smile.ch), July 21, 2001.


Bob - Why do you have to be so Pissy? It's obvious that the poster is asking about distortion caused by the film plane not being parallel to the plane of the subject - obvious to everyone but you. Seeing as how 99% of the community refers to this as a "perspective distortion" why not just try to be helpful for a change?

Regards, Wayne

-- Wayne DeWitt (wdewitt@snip.net), July 21, 2001.


"Any information on correcting the perspective on LF photography "

What's so obvious Wayne?

-- Bob Salomon (bobsalomon@mindspring.com), July 21, 2001.


Yeah Bob you're right. I'm sure that he is unaware that a camera's position may be changed - great advice by the way. It's very unlikely that English is probably a second language for this person and he just left out the word "distortion". We all know that perspective is something that has to be "corrected".

-- Wayne DeWitt (wdewitt@snip.net), July 21, 2001.


I'm glad you are clairvoyant. You are sure that he id not asking about foreshortening, or some other "distortion" rather then the change in dbject shape?

Rather then waste your time why not let the poster state what he means rther then your assuming for him?

-- Bob Salomon (bobsalomon@mindspring.com), July 22, 2001.


Oh foolish Wayne, you made the same mistake Nikon and Canon did when they named their so-called "PC" shift lenses. While they and about 100 percent of their buyers assumed "PC" meant "Perspective Correction," only 2 of us (Bob and me) knew they actually meant "Position changing." Rather than use the shift feature to "correct perspective," in other words, owners of these lenses are supposed to leave the lenses at the zero position and move the entire camera and tripod around to "correct perspective." We're glad you gave us this opportunity to clear the air!

.........

-- John (WhitmanDesign@aol.com), July 22, 2001.


John - Thank you for giving me a new perspective on an old problem.

Wayne

-- Wayne DeWitt (wdewitt@snip.net), July 22, 2001.


I would add to Bob Soloman's response, "forward or backward." I think that perspective is sometimes confused with camera manipulation, which isn't the same thing. (e.g. changing lenses versus changing the camera's location.) AA states in his book The Camera that, " . . . perspective is a function of camera-to-subject distance." He points out that changing lenses does not alter perspective.

Following Adam's lead, I prefer to think of perspective as the location of the camera, relative to the subject being photographed. While one can always argue over definitions, I find this particular definition useful. Among other things, it points out that perspective is more than just making a subject appear more or less distant in the viewfinder. While I think that composition consists of both camera manipulation and perspective, it's the latter that offers the more powerful tool for improving how a viewer can understand the image being photographed.

True in life as well as photography, it's interesting that even a small change in "perspective" can completely alter how one views an issue, or the subject in a photograph.

-- neil poulsen (neil.fg@att.net), July 23, 2001.


Neil - Look at the original question again and ask yourself:"Would someone who owns a viewcamera NOT know what perspective is?".

-- Wayne DeWitt (wdewitt@snip.net), July 23, 2001.


"forward or backward."

Does not change the perspective. Only changing the angle of the camera to the subject will change perspective.

Moving a caamera forward or back is exactly the same thing as changing lenses. You get more or less into the picture and if an object is enlared or reduced in the print so they are the same size the perspective is identical.

-- Bob Salomon (bobsalomon@mindspring.com), July 23, 2001.


Wayne: I would respond that we don't know what Pancho had in mind, because he didn't include that in his post.

Bob: To suggest that moving backwards and forwards is the same as changing lenses misses the subtlety of why it's important to distinguish between camera manipulation and perspective. By moving backwards and forwards, one changes their fundamental relationship to the image being photographed. In fact, one changes one's "angle" to every part of the image except that point at which the line of travel (in moving backwards and forwards) is normal (perpendicular) to the subject being photographed.

-- neil poulsen (neil.fg@att.net), July 23, 2001.


One of the great beauties of the English language is its versatility. Common usage can completely change the meaning of a word or a whole phrase. For example, to say "I could care less," really means "I couldn't care less." Or "Quantum leap" is used to indicate a huge change, whereas its literal and original meaning involved a shift of subatomic particles from one energy level to another, a change so small that it was virtually impossible to measure, only to calculate and infer that it has taken place. Herr Soloman states that perspective is determined only by the camera position, but in fact when the lens is raised and repositioned, only the film position is unmoved so that the lens does indeed project a different image onto it from a slightly changed perspective. Thus the common useage of this as "perspective control" is correct, both technically and linguisticly.

-- Wilhelm (bmitch@home.com), July 23, 2001.

"Moving a camera forward or back is exactly the same thing as changing lenses. You get more or less into the picture and if an object is enlared or reduced in the print so they are the same size the perspective is identical. " Dear Bob,

Come on Bob you are smarter than that! Moving the camera closer to or further away from your subject does indeed change your angle to the subject , up to a relatively distant point relative to the size of the object being photographed.

-- Ellis Vener Photography (evphoto@heartstone.com), July 23, 2001.


Ellis - You are right - Bob is much smarter than that statement. It was obviously a "Brain F*rt". Bob - Rethink your answer. Distance is perspective. The various interspatial relationships between objects and the camera creates the angular relationships that you referred to and is what we refer to as perspective. A photo taken 5' away from a 3 dimensional object will not have the same perspective as a photo taken from 50' away, regardless as to what lens you use. You know that! What were you really trying to say?

Wayne

-- Wayne DeWitt (wdewitt@snip.net), July 23, 2001.



"if an object is enlared or reduced in the print so they are the same size the perspective is identical. "

Is what I said

-- Bob Salomon (bobsalomon@mindspring.com), July 23, 2001.


First the question:

If you want to learn how to use the view camera to control the shape of objects in the frame, look at any of the basic manuals: Stroebel, Steve Simmons' _Using the View Camera_, or Ansel Adams' _The Camera_.

Second the "forward/backward" wierdness:

Of course changing subject distance is not the same as changing lenses, because the relative size of objects in the frame changes with subject distance. Adams has a nice illustration of this in _The Camera_, demonstrating that if the camera remains stationary and the lens is changed, the angle of view changes, but perspective stays the same, because objects in the foreground bear the same size relation to objects in the background (insofar as the objects in the background remain visible when the angle of view is narrowed). Move the camera, and the perspective changes, regardless of what lens is used.

-- David Goldfarb (dgoldfarb@barnard.edu), July 23, 2001.


Bob - this is what you said: "forward or backward." Does not change the perspective. Only changing the angle of the camera to the subject will change perspective.

Are you now saying that changing the distance (moving "forward or backward") thus changing the spatial relationship between the elements in a photograph and the camera does in fact change "perspective"? You can't have it both ways (even though you often try).

Wayne Wayne

-- Wayne DeWitt (wdewitt@snip.net), July 23, 2001.


Now I stutter-type. Wonder where "Pablo Pistolas" is through all of this? He started the whole thing and doesn't check-in to clarify. Is this another one of Ellis's jokes? I guess the correct answer would have been: "My perspective on LF photography is fine, no correction needed". Gray card anyone?

Wayne

-- Wayne DeWitt (wdewitt@snip.net), July 23, 2001.


It wasn't "Pablo", it was "Pancho!"

-- neil poulsen (neil.fg@att.net), July 25, 2001.

Thanks, you're right. I can't tell Peter from Paul - LOL. I had a communication with a "Pistol Pete" about a week ago - what are the odds that it's not the same guy?

-- Wayne DeWitt (wdewitt@snip.net), July 25, 2001.

I would love to post in a forum where people help each other. Arrogant and ignorant posting such as the one from Bob shouldn't have a place here.

We shouldn't go into useless theoretical debates about perspective - fact is that both the Canon and Nikon web sites write of "manipulating perspective" or "perspective control" when they talk about their Shift-Tilt lenses thus we can assume that somebody in the "beginner" section of this forum will mean - exactly that.

It was so increadibly obvious that I could cry. Sorry Bob, but you should better refrain from posting if you just want to provoke.

To Pancho: The Toyo web site somebody did quote gives you a basic idea of the movements possible. In short: If you shift a lens, you move it along the film plane, which simulates being several meters above/below/left/right of your actual camera position. If you tilt a lens, you change the plane of sharpness - normally a plane parallel to the film plane is focused onto, but if you tilt the lens, then a plane parallel to the front lens is focused onto.

Cheers,

-- David Haardt (david@haardt.net), August 15, 2001.


Bob I hate to agree with the other posters. Although your help and knowledge with respect to Linhof is very valuable, this is the second time I have seen you give this response to someone who is apparently wanting to know information on how to change the "shape" of an object in the ground glass by using movements. Ok, so some people are not as precise as you would like them to be, but maybe inquiring about if he wants to change "shape" rather than "perspective" would be a little more polite, and since you are taking the time to respond, why not include a brief explanation and or a usefull tip. e.i. Pancho look up the book view camera by leslie stroebel, his and many other view camera books will explain to you how to change the shape of an object with camera movements. That's all for me folks!

-- Jorge Gasteazoro (jorgegm@worldnet.att.net), August 15, 2001.

"Any information on correcting the perspective on LF photography " Sorry I don't see anything as "obvious" nor do I see him explaining what he is looking for.

However I can't read peoples' minds like some can.

But I would assume that the correct use of the term would benefit most people starting out so the questions they ask in the future result in correct answers.

But then to some perspective may have multiple meanings.

-- bob salomon (bob@hpmarketingcorp.com), August 15, 2001.


"But then to some perspective may have multiple meanings. " I guess that all depends on where you stand on the issue.

-- Ellis Vener Photography (evphoto@heartstone.com), August 16, 2001.

This is like the answers two parents give as to "where do babies come from?" One goes into a large explanation of the whole reproductive process while the other says "you came from Indiana".

-- Dan Smith (shooter@brigham.net), August 16, 2001.

I thought everyone came from under a cabbage leaf? Are you saying my parents lied to me? Oh the agony. Lumberjack.

-- james (james_mickelson@hotmail.com), August 18, 2001.

David Haardt (david@haardt.net stated:

>In short: If you shift a lens, you move it along the film plane, >which simulates being several meters above/below/left/right of your >actual camera position.

I'm sorry David, but if you mean that the affect is the same as raising the camera several meters, it's not true. Imagine a situation where a camera mounted 5 feet above the ground is aimed at a cube floating in the air 6 feet above the ground. Any picture that you take of the cube will show the bottom side of it. If shifting the lens upward (rise) actually "simulates being several meters above/below/left/right of your actual camera position" the camera would no longer be able to see the bottom side of the cube. What really happens when the lens is shifted up, is that the film sees a different part of the image projected by the lens and in order to keep the cube centered in the picture, it is necessary to tilt the camera down. This changes the tilt of the film plane relative to the plane of the subject, which in turn alters the "apparent" perspective. Prior to the shift, the camera would need to be tilted upward to center the cube. This would cause the right and left sides of the cube to converge. Shifting the lens would allow the camera to be tilted down to a horizontal position while still keeping the cube centered. The plane of the film and the plane of the cube (the side facing the camera) would then be parallel and the sides would no longer converge. The bottom of the cube would still appear in the picture.

Peter Caplow

-- Peter Caplow (pcaplow@prodigy.net), September 22, 2001.


I just noticed another statement by David Haardt to challenge. He said:

"......... the plane of sharpness - normally a plane parallel to the film plane ........, but if you tilt the lens, then a plane parallel to the front lens is focused onto."

Tilting the lens would never result in a plane of sharpness parallel to the front lens. With the camera level, the plane of sharpness can be made horizontal with the lens tilted far less than 90 degrees.

Peter Caplow

-- Peter Caplow (pcaplow@prodigy.net), October 02, 2001.


This has been one of the funniest discussions I have read in a long time. Thanks for the laughs.

-- K Johnson (kjohn@swbglobal.com), November 09, 2001.

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