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perspective w/ 35mm lenses?

 
 
Nostrobino
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      08-06-2004

"David Littlewood" <(E-Mail Removed)> wrote in message
news:uLrx8sA1t$(E-Mail Removed)...
> In article <mQQQc.654$(E-Mail Removed)>, Nostrobino
> <(E-Mail Removed)> writes
> >
> >
> >If you are insisting that "photographic" perspective has some different
> >meaning from "artistic" perspective, then it is you who are at odds with

the
> >way the word "perspective" is used in the Focal Encyclopedia of

Photography,
> >not I.
> >

> Utter *******s - it flatly contradicts your view.


It uses the word "perspective" to mean exactly what I have been saying it
means: the perspective of the picture as a whole.


 
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Nostrobino
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      08-06-2004

"David Littlewood" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In article <vPPQc.1778$(E-Mail Removed)>, Nostrobino
> <(E-Mail Removed)> writes
> >
> >"David Littlewood" <(E-Mail Removed)> wrote in message
> >news:(E-Mail Removed).. .
> >> In article <ZTrQc.4007$(E-Mail Removed)> , Nostrobino
> >> <(E-Mail Removed)> writes
> >> >
> >> >"David Littlewood" <(E-Mail Removed)> wrote in message
> >> >news:(E-Mail Removed).. .
> >> >[ . . . ]
> >> >>
> >> >> However, if you still wish to be in a minority of one, there is

nothing
> >> >> the rest of us can do to coerce you, and there seems no point in
> >> >
> >> >This evidently is a very important thing to you, to believe what you

> >think
> >> >everyone else believes. It isn't important to me. You need to be part

of
> >> >"the rest of us." I don't.
> >>
> >> It isn't what I want, it's what I have observed. Simply asserting that
> >> this observation translates into some psychological defect on my part

is
> >> unworthy of a genuine seeker after truth.
> >> >
> >> >The important thing to me is to get at the truth. Often this requires
> >> >relying on the help of others, which is something I always appreciate

> >when
> >> >it's given. Sometimes it requires that I think for myself, which is

> >likely
> >> >to be more work, but I am willing to do that when it seems necessary.
> >>
> >> It is clear that you have thought very deeply about this. However, the
> >> argument has arisen almost totally because you insist in describing a
> >> well-known phenomenon, which most respondents understand very well, in
> >> terms of a word that means something else.

> >
> >I have been and still am using the word exactly as your article from the
> >Focal Encyclopedia of Photography uses it, to mean perspective as it

affects
> >the entire picture. That is absolutely clear from the excerpt you
> >posted--for which I am grateful, by the way.
> >

> No you are not,


Yes, I assure you I am grateful. It so completely supports my usage that
frankly I wondered why you were posting it.


> and if you think you are you are clearly
> misunderstanding it.


You might like to try explaining what you think the terms "strong
perspective," "weak perspective" and "abnormal linear perspective" mean,
then. Just say EXACTLY what you think "strong perspective" (wide-angle
perspective) means, for example. Not just what you think produces
it--describe it.


> >
> >> >
> >> >Far from "[wishing] to be in a minority of one," my preference would

be
> >that
> >> >everyone understood what I am saying and either a) agreed with me, or

b)
> >> >corrected me by pointing out the errors in my thinking. But such

> >correction
> >> >has to hold up to rigorous examination. Merely reciting nonsense you

have
> >> >read somewhere doesn't do it, particularly as in this case when I've

> >already
> >> >read that nonsense for myself, years ago, and concluded it was

nonsense.
> >>
> >> The error has been pointed out ad nauseam. You insist in simply
> >> repeating your thoughts, most of which are quite correct, but not
> >> accepting that you are using the wrong word to encompass it.

> >
> >Again: "strong perspective," "weak perspective," "abnormal linear
> >perspective"--these are exactly the terms used by the encyclopedia

article
> >you posted, and clearly they refer to the perspective of the entire

picture.
> >
> >If your objection is to my use of "wide-angle perspective" (where your

Focal
> >Encyclopedia uses "strong perspective" or "abnormal linear perspective"

in
> >connection with wide-angle lenses), I have no great objection to

replacing
> >my term with either of those used by the encyclopedia. However, I do

think
> >that because this is a perspective associated with, and only with,
> >wide-angle lenses, "wide-angle perspective" seems a more apt term.
> >
> >
> >> >
> >> >Neither does specious reasoning impress me much (unless it's at least

> >very
> >> >imaginative), and certainly I am not dismayed by not being part of

"the
> >rest
> >> >of us." If that is so important to you, then rejoice.
> >> >
> >> I agree that you are clearly not in the business of caring what others
> >> think. Unfortunately, you insist on carrying this over into the meaning
> >> of photographic terms, which, of course, you cannot make mean what you
> >> want them to mean by any amount of argument.

> >
> >I can only again refer you to your own posted encyclopedia excerpt, which
> >takes exactly the same meaning that I have.
> >

> No it doesn't. How any native English speaker could reach this
> conclusion is a bizarre mystery. I suspect you may, after all, be
> trolling.


Be serious. Trolls don't do what I do and I don't do what trolls do.

Or are you going to redefine that word too?


>
> What it says - and I paraphrase - is that people err in thinking that


It doesn't say, hint, suggest or imply that "people err in thinking"
anything. There is absolutely nothing in the quoted piece that says anything
remotely like that. You're making that up out of thin air.


> the "wide angle perspective" comes from the use of a wide angle lens,


You agree that it does acknowledge there is such a perspective, then.


> and that it really comes from the choice of taking position normally
> used with such a lens. This is of course completely the opposite of your
> "interpretation".
>
> Read it again.


I've read it several times. It says exactly what I said it says. It
acknowledges that certain types of "abnormal linear perspective" are
"associated with" certain types of lenses ("strong" and "weak" perspective
for wide-angle and telephoto lenses respectively). This is correct. Then it
says these types of perspective are really produced by camera position and
not focal length. This is demonstrably incorrect. No camera position will
ever produce "strong perspective" (wide-angle perspective) with a long lens.
I think you know this as well as I do. Don't you?


 
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Dave Martindale
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      08-06-2004
"Nostrobino" <(E-Mail Removed)> writes:

>> Rather than go over all the issues, may I suggest you read the
>> comprehensive entry in The Focal Encyclopedia of Photography under
>> "Perspective". One pertinent quote on linear perspective* is:


>> "Since short focal length wide angle lenses tend to be used with the
>> camera relatively close to the subject and long focal length telephoto
>> lenses tend to be used with the camera at relatively large distances,
>> strong perspective is often associated with wide angle lenses and weak
>> perspective is similarly associated with telephoto lenses, but it is the
>> camera position and not the focal length or type of lens that produces
>> the abnormal linear perspective."


>Obviously this is incorrect and even self-contradictory, isn't it?


No, it's not. But they're using two slightly different meanings of
perspective in the same paragraph.

The wide angle photo shows much stronger perspective-related effects
than the telephoto shot *when both are viewed with the same visual
angle*.

On the other hand, if both are viewed with the visual angle of the
corresponding taking lens, there is no unnatural perspective at all.

It's perfectly reasonable to say that the "wide angle perspective" is
really the result of viewing the print from a greater distance,
occupying a smaller visual angle, than is correct. Similarly, the
"telephoto perspective" can be said to be the result of looking at the
print from too small a distance, with too large a visual angle.
This is just as true as saying the change in apparent perspective is due
to the change in camera lens.

So, if you assume a constant print size and viewing distance, you can
change perspective by changing lens. If you also keep about the same
amount of the in-focus object within the frame, you will have to change
the camera-subject distance in proportion to the focal length. And when
you do that, the change in apparent perspective is due to the camera
position change - not the focal length change.

On the other hand, depending on your assumptions about linear and
angular field of view, and print size and viewing distance, all of the
variables are tied together anyway. So it's a little bit untrue to say
which one "causes" and which one is "caused by". The quote above is
trying to tell you that just changing lenses *alone* will not change
perspective, while moving the camera *alone* does change perspective.
Both of these, however, also change the space that is included in the
image.

>Now to go on from that enlightened observation and then say that "it is the
>camera position and not the focal length or type of lens that produces the
>abnormal linear perspective" is clearly contradictory. If this were true,
>then it would have to be possible to change THE CAMERA POSITION to one in
>which it DOES NOT "produce the abnormal linear perspective." But you cannot.


Yes you can. If you assume a particular print size and viewing
distance, that determines the focal length of lens *and camera position*
that will give you a completely undistorted view.

>A wide-angle lens will still produce the same "abnormal linear perspective"
>or "strong perspective" (as the article calls it) wherever you place the
>camera, provided there are objects in the field of view to demonstrate it;


No, it does so as long as your viewing distance is such that the print
occupies a smaller visual angle than the original scene. That's the
only thing that's special about a wide-angle lens.

>contrariwise, a telephoto lens will still produce its own kind of
>perspective regardless of camera position.


But whether it is absolutely correct, shows "telephoto distortion", or
even "wideangle distortion" depends on viewing distance and print size.

Dave
 
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Dave Martindale
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      08-06-2004
"Nostrobino" <(E-Mail Removed)> writes:

>> But "photographic perspective" or "optical perspective" is a different


>Why should it be different?


Because there is a need to talk about what it talks about, and it's not
the same thing as "artistic perspective".

>And the Focal Encyclopedia of Photography is NOT "talking about
>photographic/optical perspective" when it speaks of "abnormal linear
>perspective" (the encyclopedia's term) such as the "strong perspective"
>associated with wide-angle lenses and "weak perspective" associated with
>telephotos?


No. It's talking about the change in apparent perspective when the lens
FL changes without a corresponding change in print viewing distance.
On the other hand, if you adjust viewing distance along with FL, then
there is no change in perspective at all - just field of view.

Both of these statements are true; why do you insist that only one can
be?

>> I just recognize those as two different meanings of
>> perspective from the one used in optics.


>How different?


What is your difference metric? The point is that they mean things that
sometimes conflict.

>Of course we almost always look at wide-angle photos "from too far away,"
>i.e. at some distance from which our angle of view is smaller than the
>camera's was when it took the picture; and contrariwise with long-lens
>photos. I have even seen in print, a number of times, the advice that even a
>fairly small print from a 135mm telephoto shot should be viewed from a
>distance of several feet in order to make its perspective "correct." That's
>nonsense, of course. Not the part about making its perspective correct,
>obviously that's true, but who on earth would actually view the print from
>such a distance? It would defeat the whole purpose of using a long lens in
>the first place.


If the purpose was to create an artificial perspective. But people
often change lenses primarily for field of view from a fixed location.

>If you are insisting that "photographic" perspective has some different
>meaning from "artistic" perspective, then it is you who are at odds with the
>way the word "perspective" is used in the Focal Encyclopedia of Photography,
>not I.


I was talking about how it was used in the discussion in this newsgroup.
And as you noted, that paragraph in the FEoP has two somewhat different
meanings in the same paragraph. You are the one insisting that there is
only One True Meaning of Perspective.

>However, when you do that with an existing wide-angle image you are simply
>throwing out most of the picture as if it were irrelevant to perspective.
>That's not valid. Every element of a picture that has a bearing on
>perspective contributes to the perspective of the picture. It is the picture
>AS A WHOLE that has perspective.


Using one definition of perspective.

>Only if you are applying some special meaning to "photographic perspective"
>that those words themselves do not carry, and that is not supported by the
>Focal Encyclopedia of Photography either. That should cause you to
>reconsider what you are insisting.


No. I have no problem with the FEoP definition. It makes perfect sense
to me. I know what it's telling me about optics. And I just don't care
if it uses "perspective" in different ways in the same paragraph. It's
not a mathematical proof; it's an informal description of a process.

>Again: That's not what the photography encyclopedia says. (It does, however,
>make a statement about perspective which is inconsistent with, and
>contradicted by, its own use of the term.)


It's contradictory only because of the way you read the paragraph, and
your insistence that there's just one meaning of the word.

>It is, though. The Focal Encyclopedia speaks of the "strong perspective"
>associated with wide-angle lenses and the "weak perspective" associated with
>telephotos, calling both forms of "abnormal linear perspective."


Which is true given their (unstated) assumptions of constant viewing
angle for the print.

>I am using the same definition as the Focal Encyclopedia of Photography.
>That's not a sufficiently authoritative source for definitions? (If you say
>their REASONING is somewhat screwy I would have to agree. But their
>DEFINITION seems fine to me.)


It's an informal description, not a precise definition. There's nothing
wrong with their reasoning, since what they state is true, but they do
not provide a listing of their assumptions nor a definition of the terms
involved.

>As long as the encyclopedia's meaning of the word agrees with my own, I
>suppose I can live with the occasional improper usage in newsgroups. But it
>would sure be better if everyone used the term correctly.


But it has two somewhat different meanings within the same paragraph.
You can't simultaneously say that the encyclopedia agrees with you, and
also say that the second half of the definition is wrong. Maybe you
should say that it half-supports your position.

Dave
 
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mcgyverjones
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      08-07-2004

"Nostrobino" <(E-Mail Removed)> wrote in message
news:H1UQc.354$(E-Mail Removed). ..
>
> "David Littlewood" <(E-Mail Removed)> wrote in message
> news:hbRyYWAcs$(E-Mail Removed)...
> > In article <hpRQc.768$(E-Mail Removed)>, Nostrobino
> > <(E-Mail Removed)> writes

snip
> > >It does indeed, and it makes no sense whatever. The same piece that

says
> "it
> > >is the camera position and not the focal length or type of lens that
> > >produces the abnormal linear perspective" just finished saying that

> "strong
> > >perspective is often associated with wide angle lenses and weak

> perspective
> > >is similarly associated with telephoto lenses." Since there is no way

on
> > >earth that camera position can make a long lens produce that "strong
> > >perspective" associated with a wide-angle lens, etc., this is

nonsensical
> on
> > >its face.

> >
> > It clearly means "is associated in the mind of the ill-informed, who are
> > incorrect." If you can't see that - and you clearly can't - then there
> > is no point in continuing.

>
> No one reading that as Standard English would make that interpretation.
> Focal Encyclopedia has gotten itself confused, as it has on other

occasions.
>
> The SIGNIFICANT thing is that they clearly use the terms "abnormal linear
> perspective," "strong perspective" and "weak perspective" to mean the
> perspective as a coherent quality of the entire picture, not some

itsy-bitsy
> teensy-weensy part taken out of the middle.
>
> > >Change the camera position all you like, the wide-angle lens will still
> > >produce what that encyclopedia calls "strong perspective," or what I

have
> > >been calling wide-angle perspective--and the telephoto lens never will.

I
> am
> > >fairly sure you know this as well as I do.


The definition of strong perspective and weak perspective is
usually illustrated with diagrams or photographs showing, for example, a
house and a mountain.
The scene is show three times to demonstrate weak, normal and strong
perspective. In each case the lens is changed (tele, prime and wide) and
the camera position adjusted closer to keep the house the same basic
size in the frame. The result is three pictures of a house and a mountain in
which the house remains about the same size and the mountain decreases in
size relative to it. The house itself displays a dramatic change in
appearance due to the change in perspective -- due solely to the change in
camera position. The wide angle lens simply allows the scene to be
encompassed in the frame.
Perspective refers to the relationship of objects to one another. This is
not really disputable, despite the efforts shown here.

>
> You're twisting yourself into some sort of linguistic pretzel to avoid
> facing the facts. The piece clearly recognizes that wide-angle lenses "are
> associated with" a certain type of perspective, and telephotos with the
> opposite type, and that people generally recognize this. If not for that
> there would be no such associations for the encyclopedia to take notice

of.
> And those are, of course, perfectly proper ordinary understandings of the
> word "perspective."
>

Unfortunately, ordinary understandings of all sorts of things are often
wrong.

>I'm frankly amazed that you can read that and so thoroughly misunderstand
> what you're reading. It's clear enough to me. The Focal Encyclopedia seems
> to have done here just what it's done with "prime lens"--first defined the
> term correctly, then (in a later edition, and without changing the

original
> definition) misused it to conform with more recently popular misusage. So
> this is no surprise to me. Perhaps the pliant editors at some point
> somewhere read that nonsense about camera position alone determining
> perspective, were gulled by it as easily as you were, and modified their
> original comments on perspective to try to incorporate the new
> fallacy--resulting in the self-contradictory mishmash you've quoted.
>
>

Do you belong to the Flat Earth society by any chance??

> >
> > I'm done wasting time on this, you just won't listen.

>
> Go in peace, brother. Think you'll ever find an actual use for

"perspective"
> as you (and the "overwhelming majority of those here" of course) have
> redefined it? It seems unlikely to me that you ever will; you've

bludgeoned
> it into about as useless a word as can be imagined.
>
>

Actually it is a useful word and concept, just commonly misunderstood.

MJ


 
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mcgyverjones
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      08-07-2004

"Nostrobino" <(E-Mail Removed)> wrote in message
news:ulUQc.360$(E-Mail Removed). ..
>
>
> You might like to try explaining what you think the terms "strong
> perspective," "weak perspective" and "abnormal linear perspective" mean,
> then. Just say EXACTLY what you think "strong perspective" (wide-angle
> perspective) means, for example. Not just what you think produces
> it--describe it.
>

I'll repeat part of what I posted elsewhere since it may have become lost in
the shuffle:

The definition of strong perspective and weak perspective is
usually illustrated with diagrams or photographs showing, for example, a
house and a mountain.
The scene is show three times to demonstrate weak, normal and strong
perspective. In each case the lens is changed (tele, prime and wide) and
the camera position adjusted closer to keep the house the same basic
size in the frame. The result is three pictures of a house and a mountain in
which the house remains about the same size and the mountain decreases in
size relative to it. The house itself displays a dramatic change in
appearance due to the change in perspective -- due solely to the change in
camera position. The wide angle lens simply allows the scene to be
encompassed in the frame.
Perspective refers to the relationship of objects to one another. This is
not really disputable, despite the efforts shown here.

>
> I've read it several times. It says exactly what I said it says. It
> acknowledges that certain types of "abnormal linear perspective" are
> "associated with" certain types of lenses ("strong" and "weak" perspective
> for wide-angle and telephoto lenses respectively). This is correct. Then

it
> says these types of perspective are really produced by camera position and
> not focal length. This is demonstrably incorrect. No camera position will
> ever produce "strong perspective" (wide-angle perspective) with a long

lens.
> I think you know this as well as I do. Don't you?
>


In order to produce a subject of the same size, you need to shoot closer to
the subject. This is why faces look so strange in a wide angle portrait. Is
a pointy face with a sloping forhead and massive nose what you mean by "wide
angle perspective".
The same shot with a tele will produce the same perspective, you simply
won't see much more than the tip of the nose.
We all know what you mean by "wide angle perspective" and we remember
thinking the same thing at one time (at least I do). But perspective is
pretty clearly defined and common misconceptions will not change the facts.


 
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Nostrobino
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      08-07-2004

"David Littlewood" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In article <vPPQc.1778$(E-Mail Removed)>, Nostrobino
> <(E-Mail Removed)> writes
> >

[ . . . ]
> >
> >I can only again refer you to your own posted encyclopedia excerpt, which
> >takes exactly the same meaning that I have.
> >

> No it doesn't. How any native English speaker could reach this
> conclusion is a bizarre mystery. I suspect you may, after all, be
> trolling.
>
> What it says - and I paraphrase - is that people err in thinking that
> the "wide angle perspective" comes from the use of a wide angle lens,
> and that it really comes from the choice of taking position normally
> used with such a lens. This is of course completely the opposite of your
> "interpretation".
>
> Read it again.


On reading it YET AGAIN, I agree with you on that point. You are right and I
was wrong: it does indeed imply that people err in attributing wide-angle
perspective to wide-angle lenses, etc.

Of course the article says that camera position being the only factor in
establishing perspective, and I have agreed from the beginning that it says
that. In this the article is obviously wrong, since as I've pointed out
several times already it is not possible to get wide-angle perspective with
a long lens REGARDLESS of camera position. One could certainly say that IF a
telephoto lens had the same angle of view as a wide-angle lens from the same
position, then its perspective WOULD be the same, but what kind of sense
would that make? If it had the same angle of view then it would be a
wide-angle lens, not a telephoto.

It says also that wide-angle lenses are generally used at close distances
and telephoto lenses at great distances, and this also is not necessarily
the case. Wide-angle lenses are commonly used to shoot landscapes, or vistas
where everything is at a great distance. Telephoto lenses are commonly used
(sometimes even quite strong ones) to shoot portraits at close distance. And
I regularly use moderately long focal lengths for table-top photography
(chiefly for items I'm selling on eBay). In all such cases long lenses still
produce long-lens perspective.

Now it is true that if all subjects were at a great distance there would be
no wide-angle perspective (regardless of the field of view), since
everything would be too far away to show perspective. That's true of long
lenses too, of course.

The most significant thing about the article from my <ahem> perspective, and
probably the reason I missed the implication that you correctly pointed out
I missed, is its implicit acceptance of the fact that perspective is a
quality of the picture IN ITS ENTIRETY, as I have said about eleventy-seven
times here. Again, this is the crux of the argument. Once you've accepted
that (as your encyclopedia does), then you have to accept that focal length
(= angle of view) is indeed a determinant of perspective just as camera
position is.


 
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Nostrobino
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      08-07-2004

"mcgyverjones" <mcgyverjones(spamout)@hotmail.com> wrote in message
news:VWYQc.48997$(E-Mail Removed) ...
>
> "Nostrobino" <(E-Mail Removed)> wrote in message
> news:ulUQc.360$(E-Mail Removed). ..
> >
> >
> > You might like to try explaining what you think the terms "strong
> > perspective," "weak perspective" and "abnormal linear perspective" mean,
> > then. Just say EXACTLY what you think "strong perspective" (wide-angle
> > perspective) means, for example. Not just what you think produces
> > it--describe it.
> >

> I'll repeat part of what I posted elsewhere since it may have become lost

in
> the shuffle:
>
> The definition of strong perspective and weak perspective is
> usually illustrated with diagrams or photographs showing, for example, a
> house and a mountain.
> The scene is show three times to demonstrate weak, normal and strong
> perspective. In each case the lens is changed (tele, prime and wide) and


You mean tele, NORMAL and wide, eh? (Please God, not yet ANOTHER misuse of
"prime"! It's bad enough already.)



> the camera position adjusted closer to keep the house the same basic
> size in the frame. The result is three pictures of a house and a mountain

in
> which the house remains about the same size and the mountain decreases in
> size relative to it.


So far, so good.


> The house itself displays a dramatic change in
> appearance due to the change in perspective -- due solely to the change in
> camera position. The wide angle lens simply allows the scene to be
> encompassed in the frame.


But in "simply allowing" that it has radically changed the perspective of
the picture AS A WHOLE. If with the camera still at the wide-angle position
you mounted a tele lens, does the narrower-angle image still have the same
perspective? No, it does not, and the reason it does not is that most of the
picture elements that previously contributed to perspective are now missing.
The PART THAT REMAINS has the same perspective that it did before, yes. That
has never been in dispute.


> Perspective refers to the relationship of objects to one another.


Absolutely! As a minor quibble I would make that "visible or apparent
relationships," but I think you will agree to that. Primarily this is a
relationship of angles, sizes and shapes, even if the angles are not always
apparent.


> This is
> not really disputable, despite the efforts shown here.


I don't know what efforts you mean, but you are certainly correct that it is
not really disputable.


>
> >
> > I've read it several times. It says exactly what I said it says. It
> > acknowledges that certain types of "abnormal linear perspective" are
> > "associated with" certain types of lenses ("strong" and "weak"

perspective
> > for wide-angle and telephoto lenses respectively). This is correct. Then

> it
> > says these types of perspective are really produced by camera position

and
> > not focal length. This is demonstrably incorrect. No camera position

will
> > ever produce "strong perspective" (wide-angle perspective) with a long

> lens.
> > I think you know this as well as I do. Don't you?
> >

>
> In order to produce a subject of the same size, you need to shoot closer

to
> the subject. This is why faces look so strange in a wide angle portrait.

Is
> a pointy face with a sloping forhead and massive nose what you mean by

"wide
> angle perspective".


That would be one example, yes.


> The same shot with a tele will produce the same perspective, you simply
> won't see much more than the tip of the nose.


And you've lost most of the original perspective.

As you said yourself, and I agreed emphatically: "Perspective refers to the
relationship of objects to one another." Those are your own words. Again, I
suggested a change to "visible or apparent relationships," but I think that
is understood anyway since it's only the perspective in some visible image
that we're considering.

Now when you start throwing away objects, specifically objects around the
edges that contribute importantly to the perspective of the picture as a
whole, you start to change the perspective OF THE PICTURE. You do not change
the perspective of the part(s) you haven't thrown away yet, of course. Take
a long-lens photo, shrink it, surround it with white space, and it still has
the same perspective it had before. We are thoroughly agreed on that, so
there is no need to go over that again and again. But if after shrinking it
you then start adding objects to fill in the surrounding white space, you
are developing an entirely new perspective, i.e. new objects with new
visible spatial relationships. This is essentially what a wide-angle lens
does.


> We all know what you mean by "wide angle perspective" and we remember
> thinking the same thing at one time (at least I do).


Then you were all correct in recognizing what was before your own eyes. What
changed that?


> But perspective is
> pretty clearly defined and common misconceptions will not change the

facts.

There is no "misconception" in seeing perspective as it actually exists.
Again (YET again), the perspective of any picture is a quality of that
picture as a whole--it is not valid to take some little part of it and say
"that's the perspective." This is the crux of the argument.


 
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Nostrobino
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      08-07-2004

"Dave Martindale" <(E-Mail Removed)> wrote in message
news:cf14rl$hmt$(E-Mail Removed)...
> "Nostrobino" <(E-Mail Removed)> writes:
>
> >> But "photographic perspective" or "optical perspective" is a different

>
> >Why should it be different?

>
> Because there is a need to talk about what it talks about, and it's not
> the same thing as "artistic perspective".
>
> >And the Focal Encyclopedia of Photography is NOT "talking about
> >photographic/optical perspective" when it speaks of "abnormal linear
> >perspective" (the encyclopedia's term) such as the "strong perspective"
> >associated with wide-angle lenses and "weak perspective" associated with
> >telephotos?

>
> No. It's talking about the change in apparent perspective when the lens
> FL changes without a corresponding change in print viewing distance.


Sure, but "apparent perspective" IS perspective. The term only refers to the
visible or apparent relationships between objects in a three-dimensional
world. Perspective is not any quality intrinsic to the objects themselves,
or their physical relationship to one another EXCEPT as perceived from a
certain point of view, over a certain angle of view. Those last six words
are the only ones on which we disagree, I think.


> On the other hand, if you adjust viewing distance along with FL, then
> there is no change in perspective at all - just field of view.
>
> Both of these statements are true; why do you insist that only one can
> be?


What we have here, as I said very early in this thread (almost my first
post, I think), is really more an argument about semantics than anything
else. I am saying that "perspective," as most people who understand the term
use it, means the angles and relationships, etc., as they are seen under
ordinary circumstances. For example, one may see a full-page extreme
wide-angle photo in a book or magazine, and a long-lens photo taking up the
facing page. No one ordinarily puts his nose down on the page so he can
squint over at the corners of the wide-angle photo to see them "properly";
neither does he put the magazine at the other end of the room so that he can
see the long-lens photo at the "proper" viewing distance. In both cases he
sees the perspective he sees, with whatever distortions are created by
"errors" in viewing distance. I put "errors" in quotes because I don't
really regard these as errors in any practical sense, though obviously they
do create differences in perspective.

I really don't think we have any disagreement whatever about the principles
involved here (unlike your discussions with Spherical Projections Jeremy).
It is only the appropriate use of the term "perspective" that we differ on.
Do you agree with this?


>
> >> I just recognize those as two different meanings of
> >> perspective from the one used in optics.

>
> >How different?

>
> What is your difference metric? The point is that they mean things that
> sometimes conflict.
>
> >Of course we almost always look at wide-angle photos "from too far away,"
> >i.e. at some distance from which our angle of view is smaller than the
> >camera's was when it took the picture; and contrariwise with long-lens
> >photos. I have even seen in print, a number of times, the advice that

even a
> >fairly small print from a 135mm telephoto shot should be viewed from a
> >distance of several feet in order to make its perspective "correct."

That's
> >nonsense, of course. Not the part about making its perspective correct,
> >obviously that's true, but who on earth would actually view the print

from
> >such a distance? It would defeat the whole purpose of using a long lens

in
> >the first place.

>
> If the purpose was to create an artificial perspective. But people
> often change lenses primarily for field of view from a fixed location.


Often, yes, but not invariably. There's a photographer who prefers very long
lenses (e.g., 300mm on a 35) for shooting half-length pictures of beautiful
girls. He doesn't NEED a long focal length; the girls are models and will be
wherever he places them, but he likes the strong look that the spatial
compression of a really long lens gives him. Similarly, ultrawide lenses are
liked by some photographers expressly FOR the pronounced wide-angle
perspective. This ability to CHOOSE perspective (for the sake of perspective
itself) by selection of focal length is a useful thing for the photographer
to have, if he's interested in doing that. Don't you agree?


>
> >If you are insisting that "photographic" perspective has some different
> >meaning from "artistic" perspective, then it is you who are at odds with

the
> >way the word "perspective" is used in the Focal Encyclopedia of

Photography,
> >not I.

>
> I was talking about how it was used in the discussion in this newsgroup.
> And as you noted, that paragraph in the FEoP has two somewhat different
> meanings in the same paragraph. You are the one insisting that there is
> only One True Meaning of Perspective.


Not necessarily, but I am saying the common usage is a perfectly valid and
proper one. It is the people who "correct" others who speak of wide-angle
perspective, for example, who are being overly restrictive about usage, and
even artificially so.


>
> >However, when you do that with an existing wide-angle image you are

simply
> >throwing out most of the picture as if it were irrelevant to perspective.
> >That's not valid. Every element of a picture that has a bearing on
> >perspective contributes to the perspective of the picture. It is the

picture
> >AS A WHOLE that has perspective.

>
> Using one definition of perspective.
>
> >Only if you are applying some special meaning to "photographic

perspective"
> >that those words themselves do not carry, and that is not supported by

the
> >Focal Encyclopedia of Photography either. That should cause you to
> >reconsider what you are insisting.

>
> No. I have no problem with the FEoP definition. It makes perfect sense
> to me. I know what it's telling me about optics. And I just don't care
> if it uses "perspective" in different ways in the same paragraph. It's
> not a mathematical proof; it's an informal description of a process.
>
> >Again: That's not what the photography encyclopedia says. (It does,

however,
> >make a statement about perspective which is inconsistent with, and
> >contradicted by, its own use of the term.)

>
> It's contradictory only because of the way you read the paragraph, and
> your insistence that there's just one meaning of the word.
>
> >It is, though. The Focal Encyclopedia speaks of the "strong perspective"
> >associated with wide-angle lenses and the "weak perspective" associated

with
> >telephotos, calling both forms of "abnormal linear perspective."

>
> Which is true given their (unstated) assumptions of constant viewing
> angle for the print.


Yes, agreed. That is the real-world case (or close enough to it) in the vast
majority of cases, I think.


>
> >I am using the same definition as the Focal Encyclopedia of Photography.
> >That's not a sufficiently authoritative source for definitions? (If you

say
> >their REASONING is somewhat screwy I would have to agree. But their
> >DEFINITION seems fine to me.)

>
> It's an informal description, not a precise definition. There's nothing
> wrong with their reasoning, since what they state is true, but they do
> not provide a listing of their assumptions nor a definition of the terms
> involved.


Right.


>
> >As long as the encyclopedia's meaning of the word agrees with my own, I
> >suppose I can live with the occasional improper usage in newsgroups. But

it
> >would sure be better if everyone used the term correctly.

>
> But it has two somewhat different meanings within the same paragraph.
> You can't simultaneously say that the encyclopedia agrees with you, and
> also say that the second half of the definition is wrong. Maybe you
> should say that it half-supports your position.


Okay, it half-supports my position and is mistaken in the other half.

But seriously, I don't think you and I really have any disagreement about
any of the geometric or optical principles involved here. Our only
disagreement is over which side is being overly restrictive in defining the
term. If someone says that camera position establishes perspective, I don't
attempt to correct them because what they is true. It is equally (and
demonstrably) true that changing focal length changes perspective; a
wide-angle lens produces a perspective which a telephoto cannot duplicate.
The DISTORTION of such an image, if any, depends on print size and viewing
distance, as you have properly pointed out. Its PERSPECTIVE however is not
changed by enlargement or reduction, or viewing distance either, any more
than in the case of cropping and enlarging the center of a wide-angle image
changes its perspective, as in the several examples much earlier in this
thread and elsewhere.


 
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Nostrobino
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      08-07-2004

"Nostrobino" <(E-Mail Removed)> wrote in message
news:uU7Rc.262$(E-Mail Removed).. .
>

[ . . . ]
>
> But seriously, I don't think you and I really have any disagreement about
> any of the geometric or optical principles involved here. Our only
> disagreement is over which side is being overly restrictive in defining

the
> term. If someone says that camera position establishes perspective, I

don't
> attempt to correct them because what they is true. It is equally (and
> demonstrably) true that changing focal length changes perspective; a
> wide-angle lens produces a perspective which a telephoto cannot duplicate.
> The DISTORTION of such an image, if any, depends on print size and viewing
> distance, as you have properly pointed out. Its PERSPECTIVE however is not
> changed by enlargement or reduction, or viewing distance either, any more
> than in the case of cropping and enlarging the center of a wide-angle

image
> changes its perspective, as in the several examples much earlier in this
> thread and elsewhere.


Just to make sure I am not misunderstood, of course I meant that "cropping
and enlarging the center of a wide-angle image" does not change the
perspective OF THAT PART.


 
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