perspective w/ 35mm lenses?

"Dave Martindale" wrote in message
...
"Nostrobino" writes:

Perspective is inseparable from field of view, is what I've been saying.

Let's say that "artistic perspective" is inseparable from field of view.

Yes!


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

Why should it be different?


thing, and does not change with field of view if relative subject and
camera (actually lens entrance pupil) remain the same. Everyone else is
talking about photographic/optical perspective. Why not just recognize
that?

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?



Yes, there are many different definitions for "perspective."

Have you never heard anyone speak of wide-angle perspective? Is my
mention
of it absolutely the first, in your experience?

Yes, I've heard that, in the context of art. I've also heard it in the
context of photography, where the author was referring to the fact that
if you shoot with a wide angle lens and look at the print from too far
away, so the apparent visual angle is varied, you get a particular sort
of distortion. I just recognize those as two different meanings of
perspective from the one used in optics.

How different?

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 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.



Do you claim--as some of "the rest of us" here have claimed--that a
wide-angle photo looks just like a long-lens photo? (I am not one of "the
rest of us," you understand.) That is, there's no such thing as a
wide-angle
look or a telephoto look?

If you think that, you haven't been reading very carefully. I claim, as
others have claimed, that there is no difference between a wide-angle
and telephoto image *over the field of view covered by both lenses when
that field of view is enlarged to the same size*.

Of course. There has never been any question about that. All you are saying
is that enlargement does not change the perspective of a small part of the
image. No one ever said it would. That is, after all, all the telephoto lens
itself is doing.

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.


That's all that is
meant by saying that the photographic perspective is the same, and it is
true.

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.



You just insist on saying that perspective means something else, that a
wide-angle shot looks different because it's wider. Well, that's
obviously true, but the difference is not in the photographic
perspective. The difference is in the FOV, and in the way the image
looks when viewed from some fixed distance (rather than the correct
distance for the FOV). You're correct about the details, except that
this is not what perspective means in photography.

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.)



Nostrobino is using "perspective" to mean something related to what's
in
the image,

In your view, perspective is NOT something related to what's in the
image?

It is not related to *how much angle of view* is contained by the
image.

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."



It is *not* the usual photographic meaning of
perspective, which is concerned with how apparent size changes with
distance, and which objects block the view of what parts of other
objects.

And how angles appear to change, and how parallel lines appear to
converge
at greater distance. All of that is part of what I mean by perspective.

These things happen when viewing a 3D scene with your eye; with no
camera involved. When you record the scene with a camera, and view the
print from the correct distance, it usually *faithfully* records this
effect, so the image is not distorted. Both WA and tele lenses
record *the same thing your eye saw* (ignoring DOF issues).

If there's a difference in angles or convergence with distance between
what your eye saw in the scene and what you see looking at a print, that
means you're looking at the print from the wrong eyepoint or the wrong
distance, which is certainly not the fault of the lens. You are
introducing the distortion in that case; it's not the camera or the
lens.

(The obvious exception to this is lenses with deliberate distortion like
a fisheye).

Perhaps we should just say that "Changing field of view changes the
Nostrobino Perspective of the image, but does not change the
photographic perspective."

Well, you could just say that "Changing the field of view changes the
perspective, but not The Rest of Us Who Read Somewhere That What We See
Isn't Really So perspective.

It's a lot easier to continue to use the existing commonly-accepted
definition of perspective, than for everyone to change to suit your
perspective on the matter.

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.)


Most of us can deal with multiple different
meanings of the word in different contexts without getting confused
and without insisting that the world change to accomodate us.

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.

"Dave Martindale" wrote in message
...
"Nostrobino" writes:

Perspective is inseparable from field of view, is what I've been saying.

Let's say that "artistic perspective" is inseparable from field of view.

Yes!


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

Why should it be different?


thing, and does not change with field of view if relative subject and
camera (actually lens entrance pupil) remain the same. Everyone else is
talking about photographic/optical perspective. Why not just recognize
that?

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?



Yes, there are many different definitions for "perspective."

Have you never heard anyone speak of wide-angle perspective? Is my
mention
of it absolutely the first, in your experience?

Yes, I've heard that, in the context of art. I've also heard it in the
context of photography, where the author was referring to the fact that
if you shoot with a wide angle lens and look at the print from too far
away, so the apparent visual angle is varied, you get a particular sort
of distortion. I just recognize those as two different meanings of
perspective from the one used in optics.

How different?

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 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.



Do you claim--as some of "the rest of us" here have claimed--that a
wide-angle photo looks just like a long-lens photo? (I am not one of "the
rest of us," you understand.) That is, there's no such thing as a
wide-angle
look or a telephoto look?

If you think that, you haven't been reading very carefully. I claim, as
others have claimed, that there is no difference between a wide-angle
and telephoto image *over the field of view covered by both lenses when
that field of view is enlarged to the same size*.

Of course. There has never been any question about that. All you are saying
is that enlargement does not change the perspective of a small part of the
image. No one ever said it would. That is, after all, all the telephoto lens
itself is doing.

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.


That's all that is
meant by saying that the photographic perspective is the same, and it is
true.

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.



You just insist on saying that perspective means something else, that a
wide-angle shot looks different because it's wider. Well, that's
obviously true, but the difference is not in the photographic
perspective. The difference is in the FOV, and in the way the image
looks when viewed from some fixed distance (rather than the correct
distance for the FOV). You're correct about the details, except that
this is not what perspective means in photography.

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.)



Nostrobino is using "perspective" to mean something related to what's
in
the image,

In your view, perspective is NOT something related to what's in the
image?

It is not related to *how much angle of view* is contained by the
image.

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."



It is *not* the usual photographic meaning of
perspective, which is concerned with how apparent size changes with
distance, and which objects block the view of what parts of other
objects.

And how angles appear to change, and how parallel lines appear to
converge
at greater distance. All of that is part of what I mean by perspective.

These things happen when viewing a 3D scene with your eye; with no
camera involved. When you record the scene with a camera, and view the
print from the correct distance, it usually *faithfully* records this
effect, so the image is not distorted. Both WA and tele lenses
record *the same thing your eye saw* (ignoring DOF issues).

If there's a difference in angles or convergence with distance between
what your eye saw in the scene and what you see looking at a print, that
means you're looking at the print from the wrong eyepoint or the wrong
distance, which is certainly not the fault of the lens. You are
introducing the distortion in that case; it's not the camera or the
lens.

(The obvious exception to this is lenses with deliberate distortion like
a fisheye).

Perhaps we should just say that "Changing field of view changes the
Nostrobino Perspective of the image, but does not change the
photographic perspective."

Well, you could just say that "Changing the field of view changes the
perspective, but not The Rest of Us Who Read Somewhere That What We See
Isn't Really So perspective.

It's a lot easier to continue to use the existing commonly-accepted
definition of perspective, than for everyone to change to suit your
perspective on the matter.

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.)


Most of us can deal with multiple different
meanings of the word in different contexts without getting confused
and without insisting that the world change to accomodate us.

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.

In article , Nostrobino
writes


This is sheer sophistry. It doesn't impress.

I have not shifted my ground.

You have. Either your memory or your veracity is flawed.

[snip]


This of course flatly refutes your
principle argument.

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.

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.

....By changing the camera position.



I suggest you read the piece cited yourself. If the overwhelming
majority of those here, and an authoritative reference source, all
disagree with you, can't you at least have some doubt.

I guess not.

I am fully agreeing with your encyclopedia's usage of "perspective," meaning
a quality that involves the entire picture. You're not really disagreeing
with THAT, are you?

It didn't say that. In fact it goes out of its way to say something
different.

Your "overwhelming majority of those here" have not been
agreeing with that usage, or there would not have been so many claims that
enlarging the center of a wide-angle shot (and discarding everything else)
"proves" that it has the same perspective as a long-lens shot. So on that
count at least, it's your encyclopedia and me against "the overwhelming
majority of those here."

Utter, utter ********. The dictionary piece says the exact opposite of
what you say, as has almost every other contributor here. Your views, as
expressed here, are simply perverse.

I'm done wasting time on this, you just won't listen.
--
David Littlewood

In article , Nostrobino
writes


This is sheer sophistry. It doesn't impress.

I have not shifted my ground.

You have. Either your memory or your veracity is flawed.

[snip]


This of course flatly refutes your
principle argument.

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.

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.

....By changing the camera position.



I suggest you read the piece cited yourself. If the overwhelming
majority of those here, and an authoritative reference source, all
disagree with you, can't you at least have some doubt.

I guess not.

I am fully agreeing with your encyclopedia's usage of "perspective," meaning
a quality that involves the entire picture. You're not really disagreeing
with THAT, are you?

It didn't say that. In fact it goes out of its way to say something
different.

Your "overwhelming majority of those here" have not been
agreeing with that usage, or there would not have been so many claims that
enlarging the center of a wide-angle shot (and discarding everything else)
"proves" that it has the same perspective as a long-lens shot. So on that
count at least, it's your encyclopedia and me against "the overwhelming
majority of those here."

Utter, utter ********. The dictionary piece says the exact opposite of
what you say, as has almost every other contributor here. Your views, as
expressed here, are simply perverse.

I'm done wasting time on this, you just won't listen.
--
David Littlewood

In article , Nostrobino
writes


This is sheer sophistry. It doesn't impress.

I have not shifted my ground.

You have. Either your memory or your veracity is flawed.

[snip]


This of course flatly refutes your
principle argument.

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.

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.

....By changing the camera position.



I suggest you read the piece cited yourself. If the overwhelming
majority of those here, and an authoritative reference source, all
disagree with you, can't you at least have some doubt.

I guess not.

I am fully agreeing with your encyclopedia's usage of "perspective," meaning
a quality that involves the entire picture. You're not really disagreeing
with THAT, are you?

It didn't say that. In fact it goes out of its way to say something
different.

Your "overwhelming majority of those here" have not been
agreeing with that usage, or there would not have been so many claims that
enlarging the center of a wide-angle shot (and discarding everything else)
"proves" that it has the same perspective as a long-lens shot. So on that
count at least, it's your encyclopedia and me against "the overwhelming
majority of those here."

Utter, utter ********. The dictionary piece says the exact opposite of
what you say, as has almost every other contributor here. Your views, as
expressed here, are simply perverse.

I'm done wasting time on this, you just won't listen.
--
David Littlewood

In article , Nostrobino
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 ******** - it flatly contradicts your view.
--
David Littlewood

In article , Nostrobino
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 ******** - it flatly contradicts your view.
--
David Littlewood

In article , Nostrobino
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 ******** - it flatly contradicts your view.
--
David Littlewood

Nostrobino wrote:

"David Littlewood" wrote in message
...

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?

The statement itself speaks of "abnormal linear perspective."

"abnormal linear" what?

"perspective."

Once again, what is it that's "abnormal" and "linear"?

"perspective."

And this results from using what kinds of lenses?

"wide angle lenses and . . . telephoto lenses."

That's not what was said. "Associated with" does not equal "results
from". Correlation does not prove causality.

In the early part of this century, a greater percentage of people who
moved to the desert southwest died of Tuberculosis than those who
remained on the east coast. At the time, one could have written:

"Since a greater percentage of people moving to the desert southwest
die from Tuberculosis and a lesser percentage of people remaining on
the east coast die from Tuberculosis, death from Tuberculosis is often
associated with moving to the desert southwest and surviving the
disease is similarly associated with remaining on the east coast."

This is logically equivalent to the first portion of the text David
quoted.

Does this mean moving to the desert southwest caused Tuberculosis in
people? Of course not. In fact, moving to the drier climate of the
desert southwest was better for people suffering from Tuberculosis.
Thus more people who were suffering from Tuberculosis would move
there, artificially inflating the per capita death rate from the
disease.

In terms of Tuberculosis deaths, the rest of the text David quoted
could be written as follows:

"... is similarly associated with remaining on the east coast, but it
is the fact that a greater percentage of Tuberculosis sufferers move
to the drier, healthier climate of the desert southwest and not the
move itself that produces the difference in death rates."

Even better... a greater per-capita percentage of people who die do
so while they are in hospitals. Does this mean that going to a
hospital is more likely to kill you than not going?

I knew those darn hostpitals were death traps...

The fact that strong perspective is often associated with wide angle
lenses does not necessarily mean that the wide angle lens is the cause
of the strong perspective. Similarly, the fact that weak perspective
is often associated with telephoto lenses does not necessarily mean
that the telephoto lens is the cause of the weak perspective. Rather,
it is the position of the camera and not the type/focal length/etc. of
the lens that produces the perspective.

Now to go on from that enlightened observation

Is it enlightened because you interpreted it as agreeing with your
position? I really do ask this in all seriousness and not to poke
at you, as it's not uncommon for one to see views similar to one's
own as "enlightened".

If enlightened for some other reason, then why wouldn't the remainder
of the same sentence be equally as enlightened?

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.

You took one complete sentence, split it into pieces, and then
analyzed each piece independently; of course it's going to appear
contradictory to you. You missed the "but" portion of the sentence
when splitting it up. The author clearly intended to show a common
fallacy in one's associating perspective with focal length, and
finished his sentence by stating that said association was incorrect
and the effect on perspective was in fact caused by something entirely
different from focal length.

Sorry to the kids reading... but I'm an evil person...

"Santa Claus is often associated with the arrival of presents on
Christmas day, but it is the children's parents who actually place
those presents under the tree."

By the same reasoning you used far above, Santa Claus exists and the
second half of the sentence is "clearly contradictory".

BJJB

Nostrobino wrote:

That may be someone I plonked. In any case, I don't see that being a
lens designer makes anyone particularly qualified to say what
perspective is or is not. It is really more a term of art than of
optical technology: there were very elaborate and complex
perspective drawings long before there were cameras--at least as
long ago as the 15th century, if I'm not mistaken.

I'm beginning to think that your definition of perspective comes from
the art world and is not necessarily equivalent and interchangeable
with the photographic definition of perspective.

I'm not going to try and define the photographic definition of
perspective, nor am I going to try and point out the differences
(if any) between the art and photographic definitions of the word.
However, based on the strong stances of you and others on this
subject there surely is a difference--perhaps a subtle one--in
terminology.

Very well, I accept the difference then. However, I must point out
again (and I'm sorry for being repetitious, but you understand that
it's unavoidable in this case with this means of communication) that
my vocabulary at least in this instance comports EXACTLY with that
of the Focal Encyclopedia that you quoted from. I am using the term
"perspective" EXACTLY as your encyclopedia uses it--to mean the
perspective of the picture as a whole, not some small part of the
picture. That has really been the crux of the argument all along,
as I've mentioned before.

The only quote I remember seeing from the Focal Encyclopedia is the
one David made regarding the incorrect association of focal length
with perspective. At no point in that quote did I see mention of
perspective of the picture as a whole, nor did I see mention of
perspective of some spall part of the picture.

Did I somehow miss a second quote somewhere in this very long
discussion thread?

BJJB