Re: That elusive term: "Perspective"
I think Darin's example of the pencil point aligned with the mountaintop (or not) is more an example of changing the "viewpoint" than the "perspective". The viewpoint is where you see something from. When you change the position of the lens, you change the viewpoint.
"Perspective" and "viewpoint" may be synonyms for, say, political writing, but have different meanings in photography and art.
In art, "perspective" usually refers to the rules of artificial one- two- three- or four-point perspective systems to simulate natural perspective, or a method of violating those rules, (as in M. C. Escher's work).
In view camera photography, "perspective" generally refers to how straight lines from natural perspective align in the rectangle of the frame, and "perspective control" traditionally refers to using the swings and tilts to "correct" the perspective of converging lines that one wants parallel to the frame edges, or similar distortion. This is also the reason for "perspective control lenses" for non-view camera photography.
And while camera movements can also be used to effect the focus, that doesn't fall under the area of "perspective control", even though it often does affect perspective.
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Re: That elusive term: "Perspective"
Quote:
Originally Posted by
iozone
well, IMHO you can call it keystone distortion if you like. the end result is that it changes the perspective of an image the same as if an artist were to change the vanishing point in a drawing. using rear swing/tilt in very small amounts will undoubtedly have a substantial impact on your composition. This change, especially in architectural subjects, can only be described by the end viewer as a change in perspective (vanishing point).
So perhaps accepting Doremus’ second distinction about “Perspective” – or “keystone distortion” as another has called it – determines whether or not back tilt (or back swing) actually “changes” perspective.
Below is a quick example from the field – where I first changed my viewpoint, then used a back swing to “control” the perspective, as Mark Sawyer describes…
Initially, I set-up in front of the camel – but that concealed its shadow.
So I re-positioned my tripod to the left, and turned the camera to right to face the camel.
This composed the shadow the way I liked – but now the wall’s masonry lines (and the front edge of the camel’s base) converged toward the right in a distracting way.
So I applied back swing (left), bringing my film plane parallel to the wall.
Presto, all the converging lines “corrected” themselves – that is, my back swing “changed” the perspective (that is, if you choose to define perspective this way).
Wonder what M.C. Escher would think… :rolleyes:
(Apologies for my shadow – the setting sun sneaked it into the scene, too.)
Toyo 45c
Fuji A 240mm/9
½ sec. @ f32
Polaroid Type 55 (shot ISO 25)
Epson 4990
Re: That elusive term: "Perspective"
Quote:
Originally Posted by
Heroique
Initially, I set-up in front of the camel – but that concealed its shadow.
So I re-positioned my tripod to the left, turning the camera back toward the camel.
This composed the shadow the way I liked – but now the wall’s masonry lines (and the front edge of the camel’s base) converged toward the right in a distracting way.
So I applied back swing (left), bringing my film plane parallel to the wall.
Presto, all the converging lines “corrected” themselves – that is, my back swing “changed” the perspective (that is, if you choose to define perspective this way).
yep, that'll do it. alternately you could find the viewpoint that you wanted, set up the camera with the back parallel to the wall (pointing to the left of the desired image), and then use front/rear shift to get the desired view on film.
actually, let me clarify- i'm not sure that using rear swings or tilts to change convergences is the proper way to do this. rather, just like one would set up a camera for architecture and use front rise (or back fall) to control vertical perspective, it seems to me that shifts would be the preferable way to control horizontal perspectives (convergences).
Re: That elusive term: "Perspective"
"When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means just what I choose it to mean - neither more nor less."
Regards
Bill
Re: That elusive term: "Perspective"
Quote:
Originally Posted by
cowanw
"When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means just what I choose it to mean - neither more nor less."
Regards
Bill
i suppose i have that coming. i'm just getting back into large format after 25 years and all of my large format thought processes aren't as clear as they once were (if they ever were!).
i'm sure we all appreciate the constructiveness of your contribution.
Re: That elusive term: "Perspective"
I didn't mean it specifically to any one post. Just that if we all define the word differently we will never be able to agree.
But if I was a bit smart ass, I apologize; I suppose the discussion is informative, so that everybody can get what they think, straight in their minds, so we all can get things in perspective.
Regards
Bill
Re: That elusive term: "Perspective"
Darin's explanation sure helps me understand why back shift is used to make a panoramic, from say two 4x5s instead of using front shift. I never could understand the difference until now.
thanks,
chris
Re: That elusive term: "Perspective"
Anytime you move the lens, be it swings, tilts, rise, shift, or moving the whole camera, you are changing perspective. By Applying same movements to the back does not change perspective.
Re: That elusive term: "Perspective"
Quote:
I think Darin's example of the pencil point aligned with the mountaintop (or not) is more an example of changing the "viewpoint" than the "perspective". The viewpoint is where you see something from. When you change the position of the lens, you change the viewpoint.
viewpoint and perspective are the same...are they not?
Re: That elusive term: "Perspective"
Funny thing happened last night. I had friends over and they wanted to see the new 4x5. I set it up and gave them a basic explanation of what it does and how it differs from a regular camera. One guy is an architect. When I got to the rear standard he chimes in, "it changes perspective" and proceeded to explain that he meant that it changes convergence, etc.
I thought of this thread!
From his background "perspective" doesn't mean exactly what we as photographers mean by the word. Most of the discussion here is like that--using the word "perspective" in different ways.
--Darin