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perspective w/ 35mm lenses?



 
 
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  #21  
Old August 2nd 04, 03:51 AM
Nostrobino
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Posts: n/a
Default perspective w/ 35mm lenses?


"DSphotog" wrote in message
. net...

"Nostrobino" wrote in message
m...

wrote in message
...
On 16 Jul 2004 02:16:09 GMT, ospam (PrincePete01)
wrote:
what i'm really trying to get is this....would a 50mm lens used on a

digital body (effective
75mm coverage) be an acceptable portrait lens?

peter

Actually, it will not make any deifference at all. Lens focal length
has nothing to do with perspective.


That depends on how you use the term "perspective." In the way that most
people use it, it definitely is related to focal length.


In fact perspective wasn't even
invintet until railroads became popular. There is no such thing as a
telephoto/wide angle look. I just looks like there is a telephoto/
wideangle look


If it "just LOOKS" that way, then obviously there IS such a thing as a

wide
angle or telephoto look.


and if you really knew how to look, it wouldn't look
like there is a telephoto/wideangle to look at in the first place.


This is the fallacy of that whole argument. People look at photos as

they
are, and any different appearance "if [they] really knew how to look" is
irrelevant.

The way this argument usually goes is something like this: If you take

two
photos of the same subject from the same position they have the same
perspective, whether you shoot with a wide angle, normal or telephoto

lens.

Anyone who actually does this will see VERY OBVIOUS differences in
perspective. But the argument goes along these lines: Aha, but if you

took
the central portion of the wide angle shot and enlarged it so that its

field
of view would be exactly the same as that of the normal or tele lens,

then
the perspective would also be exactly the same.

Yes, that's true, but people DON'T do that. The full shot taken with a

wide
angle lens has a wide-angle perspective, and the shot taken with a

telephoto
lens has a telephoto perspective. If you take a wide-angle shot and crop

out
everything except what would appear in a telephoto shot, all you've done

is
EMULATED the telephoto lens. The original PERSPECTIVE has been destroyed

by
what you removed.


This can be proven by always using a 7mm lens (any format) and adding
a twelve foot post to your enlarger. You do have to protect your
wideangle prints from nose gease because the proper viewing distance
is focal length times magnification.


But no one CARES about "proper viewing distance." If we see a shot taken
with a very long telephoto, we do not put it at the far end of a room

just
so we can look at it in the "proper perspective." That would, in fact,
defeat the whole purpose of using a long lens in the first place.

Similarly, no one puts his nose down on the print just because it was

shot
with an ultra-wide lens.


This does mean the proper viewing
distance for an 8X10inch print from a full from a 35mm camera equiped
with a 500mm lens is eighty inches. Everyone know all this and in fact
is a given on at least one news list.


This sort of nonsense has been often repeated, that much is true. It's

still
nonsense, no matter how often it's repeated.

If it were true and/or relevant, no one would ever bother using a 500mm

or
other long tele lens. What would be the point, if the print had to be

viewed
from some unnaturally and inconveniently long distance?

READ AND LEARN PLEASE:

perspective, (per-spčk¹tīv) in art, any method employed to represent
three-dimensional space on a flat or relief surface. Linear perspective,

in
the modern sense, was probably first formulated in 15th-cent. Florence by
the architects Brunelleschi and Alberti. It depends on a system in which
objects are foreshortened as they recede into the distance, with lines
converging to a vanishing point that corresponds to the spectator's
viewpoint. Used by such Renaissance artists as Donatello, Masaccio, and
Piero della Francesca, the technique of linear perspective exerted an
enormous influence on subsequent Western art. Its use declined in the 20th
cent. Aerial (atmospheric) perspective, which is based on the perception
that contrasts of color and shade appear greater in near objects than in
far, and that warm colors appear to advance and cool colors to recede, was
developed primarily by Leonardo da Vinci, in the West, and was often used

in
East Asian art, where zones of mist were often used to separate near and

far
space.


Yes, there are several definitions for perspective.

Here are some from the American Heritage Dictionary of the English Lanuage,
Third Edition:

per·spec·tive (p?r-spek'tiv) noun


1. The technique of representing three-dimensional objects and depth
relationships on a two-dimensional surface.

2. a. A view or vista. b. A mental view or outlook: "It is useful
occasionally to look at the past to gain a perspective on the present"
(Fabian Linden).

3. The appearance of objects in depth as perceived by normal binocular
vision.

4. a. The relationship of aspects of a subject to each other and to a whole:
a perspective of history; a need to view the problem in the proper
perspective. b. Subjective evaluation of relative significance; a point of
view: the perspective of the displaced homemaker. c. The ability to perceive
things in their actual interrelations or comparative importance: tried to
keep my perspective throughout the crisis.



These are ordinary, everyday definitions in Standard English., which
everyone can easily understand. Note that there is NOTHING in them--any of
them--which declares that distance alone must be the determinant of
perspective.


  #22  
Old August 2nd 04, 04:02 AM
Nostrobino
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?


"David Dyer-Bennet" wrote in message
...
"Nostrobino" writes:

wrote in message
...
On 16 Jul 2004 02:16:09 GMT, ospam (PrincePete01)
wrote:
what i'm really trying to get is this....would a 50mm lens used on a

digital body (effective
75mm coverage) be an acceptable portrait lens?

peter

Actually, it will not make any deifference at all. Lens focal length
has nothing to do with perspective.


That depends on how you use the term "perspective." In the way that most
people use it, it definitely is related to focal length.


Um, no. If you show people two photos taken from the exact same
location with widely differing focal lengths and ask them if the
perspective is the same or different, they'll either have no idea what
you're talking about, or decide it's the same in the two photos.


I doubt very much that any ordinary person looking at two photos taken from
the same position, one with a 17mm lens and the other with a 300mm lens,
would decide they had the same perspective. Most people would understand
"perspective" well enough to realize they were looking at pictures with
radically different perspectives.



If you're standing on a spot and want to change the perspective of
your view, changing lenses will not help.


That would be true if you were shooting a perfectly two-dimensional wall
running perpendicular to your lens axis and filling the frame. But only in
that unusual circumstance.


  #23  
Old August 2nd 04, 04:02 AM
Nostrobino
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?


"David Dyer-Bennet" wrote in message
...
"Nostrobino" writes:

wrote in message
...
On 16 Jul 2004 02:16:09 GMT, ospam (PrincePete01)
wrote:
what i'm really trying to get is this....would a 50mm lens used on a

digital body (effective
75mm coverage) be an acceptable portrait lens?

peter

Actually, it will not make any deifference at all. Lens focal length
has nothing to do with perspective.


That depends on how you use the term "perspective." In the way that most
people use it, it definitely is related to focal length.


Um, no. If you show people two photos taken from the exact same
location with widely differing focal lengths and ask them if the
perspective is the same or different, they'll either have no idea what
you're talking about, or decide it's the same in the two photos.


I doubt very much that any ordinary person looking at two photos taken from
the same position, one with a 17mm lens and the other with a 300mm lens,
would decide they had the same perspective. Most people would understand
"perspective" well enough to realize they were looking at pictures with
radically different perspectives.



If you're standing on a spot and want to change the perspective of
your view, changing lenses will not help.


That would be true if you were shooting a perfectly two-dimensional wall
running perpendicular to your lens axis and filling the frame. But only in
that unusual circumstance.


  #24  
Old August 2nd 04, 04:25 AM
David Dyer-Bennet
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?

"Nostrobino" writes:

Yes, there are several definitions for perspective.

Here are some from the American Heritage Dictionary of the English Lanuage,
Third Edition:

per·spec·tive (p?r-spek'tiv) noun


1. The technique of representing three-dimensional objects and depth
relationships on a two-dimensional surface.

2. a. A view or vista. b. A mental view or outlook: "It is useful
occasionally to look at the past to gain a perspective on the present"
(Fabian Linden).

3. The appearance of objects in depth as perceived by normal binocular
vision.

4. a. The relationship of aspects of a subject to each other and to a whole:
a perspective of history; a need to view the problem in the proper
perspective. b. Subjective evaluation of relative significance; a point of
view: the perspective of the displaced homemaker. c. The ability to perceive
things in their actual interrelations or comparative importance: tried to
keep my perspective throughout the crisis.



These are ordinary, everyday definitions in Standard English., which
everyone can easily understand. Note that there is NOTHING in them--any of
them--which declares that distance alone must be the determinant of
perspective.


Numbers one, three, and four describe an aspect of photographs that is
determined by camera position relative to the subject and is *not*
influenced by lens focal length. Number two is a general term, not a
specific technical term.

None of those definitions says that in photography it's only
influenced by camera position, no. So what? That's a general
dictionary definition, not an art text or a photography text or an
optics text.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/
  #25  
Old August 2nd 04, 04:25 AM
David Dyer-Bennet
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?

"Nostrobino" writes:

Yes, there are several definitions for perspective.

Here are some from the American Heritage Dictionary of the English Lanuage,
Third Edition:

per·spec·tive (p?r-spek'tiv) noun


1. The technique of representing three-dimensional objects and depth
relationships on a two-dimensional surface.

2. a. A view or vista. b. A mental view or outlook: "It is useful
occasionally to look at the past to gain a perspective on the present"
(Fabian Linden).

3. The appearance of objects in depth as perceived by normal binocular
vision.

4. a. The relationship of aspects of a subject to each other and to a whole:
a perspective of history; a need to view the problem in the proper
perspective. b. Subjective evaluation of relative significance; a point of
view: the perspective of the displaced homemaker. c. The ability to perceive
things in their actual interrelations or comparative importance: tried to
keep my perspective throughout the crisis.



These are ordinary, everyday definitions in Standard English., which
everyone can easily understand. Note that there is NOTHING in them--any of
them--which declares that distance alone must be the determinant of
perspective.


Numbers one, three, and four describe an aspect of photographs that is
determined by camera position relative to the subject and is *not*
influenced by lens focal length. Number two is a general term, not a
specific technical term.

None of those definitions says that in photography it's only
influenced by camera position, no. So what? That's a general
dictionary definition, not an art text or a photography text or an
optics text.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/
  #26  
Old August 2nd 04, 06:24 AM
Jeremy Nixon
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?

Nostrobino wrote:

Yes. However, a wide-angle lens includes more objects and therefore has more
and different relationships, than a long lens.


No; it has more relationships, but the ones it shares are exactly the same.

Wide-angle lenses tend to exaggerate differences in distance, while
telephoto (or more correctly, long-focus lenses whether they are true
telephotos or not) produce the effect of spatial compression. These are
clearly differences in perspective, as it is perceived by the viewer.


Except that the effect is not in any way the result of the focal length of
the lens, but of the magnification.

If that were true, wide-angle photos and long-lens photos would appear to
have the same perspective. They do not. I know you know this as well as I
do.


Except that they quite clearly do.

Wide-angle photos taken from the same distance do not have a "telephoto
look," do they?


There is no such thing as a "telephoto look". The "look" you are talking
about is a product of magnification, and the relationship between objects
in the picture is exactly the same as it would be from a wide angle lens.
You can easily prove this to yourself by taking two pictures and comparing
them.

If I shoot buildings with an ultra-wide lens with the camera tilted upward,
the sides of those buildings will converge toward the top in a way that
appears very distorted, very spatially exaggerated. This is clearly a matter
of perspective, and meets every ordinary definition for perspective. If I
shoot the same buildings from the same position with a long lens, there will
be no such effect; on the contrary there will be a flattening and spatial
compression as verticals are made more parallel and distance differences are
made to appear less.


Except that this just plain won't happen. You will merely see less of the
buildings, and thus not notice that the parallel lines are doing exactly
the same thing in both pictures.

Changing the field of view (from the same position) CHANGES the perspective,
is what I am saying.


And this is incorrect.

Just remember that perspective is something that involves THE WHOLE PICTURE.


No, it's not.

Those things aren't what matters as much as perspective. With 35mm for
example, why does anyone use a 105mm or so lens for portraiture? Because a
longish lens gives a more flattering perspective.


No, that's not why. It's because standing farther away from the subject
gives a more flattering perspective, and the telephoto lens lets you fill the
frame with the subject from farther away. The long lens absolutely, clearly,
provably does *not* flatten anything.

You could use a 28mm lens and move in to fill the frame just the same,
couldn't you? But the results would be horrid. Perspective is what makes
the difference.


Yes, and as you said, you've moved in to fill the frame, changing the
perspective. Try it from the same place, and the perspective will be
exactly the same as the telephoto shot; the features of the person's
face will have the same relationship to each other and to their
surroundings.

If you used the 28mm from the original 105mm position would the perspective
be the same (this is what you're claiming, right)?


Yes, it would.

No, it would not. The 28 would produce not only a smaller image of the
subject, but also more convergence in parallel lines outside of the subject


It would produce a smaller, but identical image of the subject, and the
parallel lines would be the same except that you'd see more of them, and
thus be fooled into thinking there is more convergence when in fact there
is not.

How often do you have to see a certain look with your own eyes before you
admit that that look does, in fact, exist?


The wide-angle look is a product of the larger field of view, not of the
perspective. The reason things seem to distort at the edges of a wide-
angle image is because you are projecting a spherical image onto a flat
plane, and the larger the area of the sphere you use, the more that will
result in "distortion" from what you expect to see (but in fact it's not
distorted, it's just one possible projection; a fisheye lens produces
another, equally valid, projection, but one that differs from the way
we assemble images in our brain and therefore one that looks weird).

--
Jeremy |
  #27  
Old August 2nd 04, 06:24 AM
Jeremy Nixon
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?

Nostrobino wrote:

Yes. However, a wide-angle lens includes more objects and therefore has more
and different relationships, than a long lens.


No; it has more relationships, but the ones it shares are exactly the same.

Wide-angle lenses tend to exaggerate differences in distance, while
telephoto (or more correctly, long-focus lenses whether they are true
telephotos or not) produce the effect of spatial compression. These are
clearly differences in perspective, as it is perceived by the viewer.


Except that the effect is not in any way the result of the focal length of
the lens, but of the magnification.

If that were true, wide-angle photos and long-lens photos would appear to
have the same perspective. They do not. I know you know this as well as I
do.


Except that they quite clearly do.

Wide-angle photos taken from the same distance do not have a "telephoto
look," do they?


There is no such thing as a "telephoto look". The "look" you are talking
about is a product of magnification, and the relationship between objects
in the picture is exactly the same as it would be from a wide angle lens.
You can easily prove this to yourself by taking two pictures and comparing
them.

If I shoot buildings with an ultra-wide lens with the camera tilted upward,
the sides of those buildings will converge toward the top in a way that
appears very distorted, very spatially exaggerated. This is clearly a matter
of perspective, and meets every ordinary definition for perspective. If I
shoot the same buildings from the same position with a long lens, there will
be no such effect; on the contrary there will be a flattening and spatial
compression as verticals are made more parallel and distance differences are
made to appear less.


Except that this just plain won't happen. You will merely see less of the
buildings, and thus not notice that the parallel lines are doing exactly
the same thing in both pictures.

Changing the field of view (from the same position) CHANGES the perspective,
is what I am saying.


And this is incorrect.

Just remember that perspective is something that involves THE WHOLE PICTURE.


No, it's not.

Those things aren't what matters as much as perspective. With 35mm for
example, why does anyone use a 105mm or so lens for portraiture? Because a
longish lens gives a more flattering perspective.


No, that's not why. It's because standing farther away from the subject
gives a more flattering perspective, and the telephoto lens lets you fill the
frame with the subject from farther away. The long lens absolutely, clearly,
provably does *not* flatten anything.

You could use a 28mm lens and move in to fill the frame just the same,
couldn't you? But the results would be horrid. Perspective is what makes
the difference.


Yes, and as you said, you've moved in to fill the frame, changing the
perspective. Try it from the same place, and the perspective will be
exactly the same as the telephoto shot; the features of the person's
face will have the same relationship to each other and to their
surroundings.

If you used the 28mm from the original 105mm position would the perspective
be the same (this is what you're claiming, right)?


Yes, it would.

No, it would not. The 28 would produce not only a smaller image of the
subject, but also more convergence in parallel lines outside of the subject


It would produce a smaller, but identical image of the subject, and the
parallel lines would be the same except that you'd see more of them, and
thus be fooled into thinking there is more convergence when in fact there
is not.

How often do you have to see a certain look with your own eyes before you
admit that that look does, in fact, exist?


The wide-angle look is a product of the larger field of view, not of the
perspective. The reason things seem to distort at the edges of a wide-
angle image is because you are projecting a spherical image onto a flat
plane, and the larger the area of the sphere you use, the more that will
result in "distortion" from what you expect to see (but in fact it's not
distorted, it's just one possible projection; a fisheye lens produces
another, equally valid, projection, but one that differs from the way
we assemble images in our brain and therefore one that looks weird).

--
Jeremy |
  #28  
Old August 2nd 04, 02:04 PM
Nostrobino
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?


"David Dyer-Bennet" wrote in message
...
"Nostrobino" writes:

Yes, there are several definitions for perspective.

Here are some from the American Heritage Dictionary of the English

Lanuage,
Third Edition:

per·spec·tive (p?r-spek'tiv) noun


1. The technique of representing three-dimensional objects and depth
relationships on a two-dimensional surface.

2. a. A view or vista. b. A mental view or outlook: "It is useful
occasionally to look at the past to gain a perspective on the present"
(Fabian Linden).

3. The appearance of objects in depth as perceived by normal binocular
vision.

4. a. The relationship of aspects of a subject to each other and to a

whole:
a perspective of history; a need to view the problem in the proper
perspective. b. Subjective evaluation of relative significance; a point

of
view: the perspective of the displaced homemaker. c. The ability to

perceive
things in their actual interrelations or comparative importance: tried

to
keep my perspective throughout the crisis.



These are ordinary, everyday definitions in Standard English., which
everyone can easily understand. Note that there is NOTHING in them--any

of
them--which declares that distance alone must be the determinant of
perspective.


Numbers one, three, and four describe an aspect of photographs that is
determined by camera position relative to the subject and is *not*
influenced by lens focal length. Number two is a general term, not a
specific technical term.


Actually the only one relevant to this discussion is No. 1, "The technique
of representing three-dimensional objects and depth relationships on a
two-dimensional surface."


None of those definitions says that in photography it's only
influenced by camera position, no. So what? That's a general
dictionary definition, not an art text or a photography text or an
optics text.


Sure, but the crux of this argument is whether "perspective" is properly
used as ordinary people who understand the word do in fact use it, as
opposed to some supposedly technically correct definition with restrictions
invented by someone who does not appear to have fully understood what he was
talking about. (I agree that the latter has gained wide currency as we see
here; I read the same nonsense many years ago myself.)

From the title of this thread and the first quoted post available to me
here, it seems that the original poster (the original post is not available
to me here, though I suppose I could search Google for it) was asking about
perspective with 35mm SLR lenses on a digital SLR which would effectively
increase the f.l. by a factor of 1.5.

The first post I have here gives the reply, "Actually, it will not make any
deifference at all. Lens focal length has nothing to do with perspective. In
fact perspective wasn't even invintet until railroads became popular. There
is no such thing as a telephoto/wide angle look. . . ."

This is what I originally disputed. OF COURSE there IS such a thing as a
telephoto look or a wide-angle look, that particular look in either case IS
because of the characteristics of perspective, those characteristics ARE
related to the focal length of the lens used, and anyone whose eyes and
brain work together properly is able to see this.

Can you seriously tell me that if, for example, you walked around a city
with an SLR and two lenses, a 20mm and a 200mm, taking hundreds of pictures
and interchanging the lenses frequently, taking no notes about distance or
which lens was used for which shot, etc., then viewing the photos even
months or years later you would NOT be able to tell which shots were taken
with the 20 and which with the 200?

I don't think you are going to tell me that. Now tell me HOW you could tell
the difference.

What I am saying is that people who faithfully repeat "There is no such
thing as 'wide-angle perspective'--perspective depends solely on shooting
position" are simply refusing to believe the evidence of their own eyes, and
refusing to believe it on the basis of some nonsense they have read. Yes, I
grant you it is widely circulated nonsense, but nonsense all the same.

Ordinary people who have not had the dubious benefit of such "learned"
explications can immediately see that most photos taken with a 24mm lens,
for example, do indeed (when viewed in their entirety) have a wide-angle
perspective.


  #29  
Old August 2nd 04, 02:36 PM
Nostrobino
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?


"Jeremy Nixon" wrote in message
...
Nostrobino wrote:

Yes. However, a wide-angle lens includes more objects and therefore has

more
and different relationships, than a long lens.


No; it has more relationships, but the ones it shares are exactly the

same.

It is the relationships NOT SHARED that make the difference.


Wide-angle lenses tend to exaggerate differences in distance, while
telephoto (or more correctly, long-focus lenses whether they are true
telephotos or not) produce the effect of spatial compression. These are
clearly differences in perspective, as it is perceived by the viewer.


Except that the effect is not in any way the result of the focal length of
the lens, but of the magnification.


The magnification IS a direct result of the focal length used.



If that were true, wide-angle photos and long-lens photos would appear

to
have the same perspective. They do not. I know you know this as well as

I
do.


Except that they quite clearly do.


You are saying that you really cannot see any difference in perspective
between a shot taken with a 24mm lens and one taken with a 200mm lens?
Remarkable.



Wide-angle photos taken from the same distance do not have a "telephoto
look," do they?


There is no such thing as a "telephoto look".


You honestly BELIEVE this? Looking at photos taken with 200mm and 300mm
lenses, you would have no clue from their appearance that they'd be taken
with long lenses? Remarkable.


The "look" you are talking
about is a product of magnification,


Take a 24mm shot and magnify it all you like, it will never (when viewed in
its entirety) look like a 300mm shot.


and the relationship between objects
in the picture is exactly the same as it would be from a wide angle lens.
You can easily prove this to yourself by taking two pictures and comparing
them.

If I shoot buildings with an ultra-wide lens with the camera tilted

upward,
the sides of those buildings will converge toward the top in a way that
appears very distorted, very spatially exaggerated. This is clearly a

matter
of perspective, and meets every ordinary definition for perspective. If

I
shoot the same buildings from the same position with a long lens, there

will
be no such effect; on the contrary there will be a flattening and

spatial
compression as verticals are made more parallel and distance differences

are
made to appear less.


Except that this just plain won't happen. You will merely see less of the
buildings,


Of course.


and thus not notice that the parallel lines are doing exactly
the same thing in both pictures.


There is nothing to notice or not notice; many parallel lines in the
wide-angle shot do not even exist in the long-lens shot.


Changing the field of view (from the same position) CHANGES the

perspective,
is what I am saying.


And this is incorrect.

Just remember that perspective is something that involves THE WHOLE

PICTURE.

No, it's not.


Of course it is. This is really the sticking point, as I have indicated
before. When one speaks of any picture as having perspective, it is the
whole picture that one is talking about. If you start zeroing in on smaller
and smaller components of the picture, you not only change the perspective
as you do so but could eventually reach a point where there is no
perspective at all.



Those things aren't what matters as much as perspective. With 35mm for
example, why does anyone use a 105mm or so lens for portraiture? Because

a
longish lens gives a more flattering perspective.


No, that's not why. It's because standing farther away from the subject
gives a more flattering perspective, and the telephoto lens lets you fill

the
frame with the subject from farther away. The long lens absolutely,

clearly,
provably does *not* flatten anything.

You could use a 28mm lens and move in to fill the frame just the same,
couldn't you? But the results would be horrid. Perspective is what makes
the difference.


Yes, and as you said, you've moved in to fill the frame, changing the
perspective. Try it from the same place, and the perspective will be
exactly the same as the telephoto shot; the features of the person's
face will have the same relationship to each other and to their
surroundings.

If you used the 28mm from the original 105mm position would the

perspective
be the same (this is what you're claiming, right)?


Yes, it would.

No, it would not. The 28 would produce not only a smaller image of the
subject, but also more convergence in parallel lines outside of the

subject

It would produce a smaller, but identical image of the subject,


"Smaller but identical" is a contradiction in terms.


and the
parallel lines would be the same except that you'd see more of them,


Then they would not be "the same."


and
thus be fooled into thinking there is more convergence when in fact there
is not.


The convergence is not really there anyway, i.e. parallel lines do not
converge in a three-dimensional world. It is only the APPEARANCE of
convergence that lends any picture its perspective. It is the exaggerated
convergence of parallels in a wide-angle shot that give it the familiar and
easily seen (no matter how strenuously denied) wide-angle perspective.



How often do you have to see a certain look with your own eyes before

you
admit that that look does, in fact, exist?


The wide-angle look is a product of the larger field of view, not of the
perspective. The reason things seem to distort at the edges of a wide-
angle image is because you are projecting a spherical image onto a flat
plane,


No, not a spherical image. What is projected onto the flat plane is the
two-dimensional representation of a three-dimensional world. That's
perspective.


and the larger the area of the sphere you use, the more that will
result in "distortion" from what you expect to see (but in fact it's not
distorted, it's just one possible projection; a fisheye lens produces
another, equally valid, projection, but one that differs from the way
we assemble images in our brain and therefore one that looks weird).


The fisheye lens does project a spherical image (more correctly, an
inside-the-hemisphere image) onto a flat plane. But I don't believe we have
any real disagreement about that, and it's really off the subject of
perspective anyway. Perspective, at least in the classical sense, is only
obtained with (reasonably) rectilinear lenses.

We could probably get into a discussion of non-classical perspective with
fisheye lenses, but it would make my teeth hurt.


  #30  
Old August 2nd 04, 02:36 PM
Nostrobino
external usenet poster
 
Posts: n/a
Default perspective w/ 35mm lenses?


"Jeremy Nixon" wrote in message
...
Nostrobino wrote:

Yes. However, a wide-angle lens includes more objects and therefore has

more
and different relationships, than a long lens.


No; it has more relationships, but the ones it shares are exactly the

same.

It is the relationships NOT SHARED that make the difference.


Wide-angle lenses tend to exaggerate differences in distance, while
telephoto (or more correctly, long-focus lenses whether they are true
telephotos or not) produce the effect of spatial compression. These are
clearly differences in perspective, as it is perceived by the viewer.


Except that the effect is not in any way the result of the focal length of
the lens, but of the magnification.


The magnification IS a direct result of the focal length used.



If that were true, wide-angle photos and long-lens photos would appear

to
have the same perspective. They do not. I know you know this as well as

I
do.


Except that they quite clearly do.


You are saying that you really cannot see any difference in perspective
between a shot taken with a 24mm lens and one taken with a 200mm lens?
Remarkable.



Wide-angle photos taken from the same distance do not have a "telephoto
look," do they?


There is no such thing as a "telephoto look".


You honestly BELIEVE this? Looking at photos taken with 200mm and 300mm
lenses, you would have no clue from their appearance that they'd be taken
with long lenses? Remarkable.


The "look" you are talking
about is a product of magnification,


Take a 24mm shot and magnify it all you like, it will never (when viewed in
its entirety) look like a 300mm shot.


and the relationship between objects
in the picture is exactly the same as it would be from a wide angle lens.
You can easily prove this to yourself by taking two pictures and comparing
them.

If I shoot buildings with an ultra-wide lens with the camera tilted

upward,
the sides of those buildings will converge toward the top in a way that
appears very distorted, very spatially exaggerated. This is clearly a

matter
of perspective, and meets every ordinary definition for perspective. If

I
shoot the same buildings from the same position with a long lens, there

will
be no such effect; on the contrary there will be a flattening and

spatial
compression as verticals are made more parallel and distance differences

are
made to appear less.


Except that this just plain won't happen. You will merely see less of the
buildings,


Of course.


and thus not notice that the parallel lines are doing exactly
the same thing in both pictures.


There is nothing to notice or not notice; many parallel lines in the
wide-angle shot do not even exist in the long-lens shot.


Changing the field of view (from the same position) CHANGES the

perspective,
is what I am saying.


And this is incorrect.

Just remember that perspective is something that involves THE WHOLE

PICTURE.

No, it's not.


Of course it is. This is really the sticking point, as I have indicated
before. When one speaks of any picture as having perspective, it is the
whole picture that one is talking about. If you start zeroing in on smaller
and smaller components of the picture, you not only change the perspective
as you do so but could eventually reach a point where there is no
perspective at all.



Those things aren't what matters as much as perspective. With 35mm for
example, why does anyone use a 105mm or so lens for portraiture? Because

a
longish lens gives a more flattering perspective.


No, that's not why. It's because standing farther away from the subject
gives a more flattering perspective, and the telephoto lens lets you fill

the
frame with the subject from farther away. The long lens absolutely,

clearly,
provably does *not* flatten anything.

You could use a 28mm lens and move in to fill the frame just the same,
couldn't you? But the results would be horrid. Perspective is what makes
the difference.


Yes, and as you said, you've moved in to fill the frame, changing the
perspective. Try it from the same place, and the perspective will be
exactly the same as the telephoto shot; the features of the person's
face will have the same relationship to each other and to their
surroundings.

If you used the 28mm from the original 105mm position would the

perspective
be the same (this is what you're claiming, right)?


Yes, it would.

No, it would not. The 28 would produce not only a smaller image of the
subject, but also more convergence in parallel lines outside of the

subject

It would produce a smaller, but identical image of the subject,


"Smaller but identical" is a contradiction in terms.


and the
parallel lines would be the same except that you'd see more of them,


Then they would not be "the same."


and
thus be fooled into thinking there is more convergence when in fact there
is not.


The convergence is not really there anyway, i.e. parallel lines do not
converge in a three-dimensional world. It is only the APPEARANCE of
convergence that lends any picture its perspective. It is the exaggerated
convergence of parallels in a wide-angle shot that give it the familiar and
easily seen (no matter how strenuously denied) wide-angle perspective.



How often do you have to see a certain look with your own eyes before

you
admit that that look does, in fact, exist?


The wide-angle look is a product of the larger field of view, not of the
perspective. The reason things seem to distort at the edges of a wide-
angle image is because you are projecting a spherical image onto a flat
plane,


No, not a spherical image. What is projected onto the flat plane is the
two-dimensional representation of a three-dimensional world. That's
perspective.


and the larger the area of the sphere you use, the more that will
result in "distortion" from what you expect to see (but in fact it's not
distorted, it's just one possible projection; a fisheye lens produces
another, equally valid, projection, but one that differs from the way
we assemble images in our brain and therefore one that looks weird).


The fisheye lens does project a spherical image (more correctly, an
inside-the-hemisphere image) onto a flat plane. But I don't believe we have
any real disagreement about that, and it's really off the subject of
perspective anyway. Perspective, at least in the classical sense, is only
obtained with (reasonably) rectilinear lenses.

We could probably get into a discussion of non-classical perspective with
fisheye lenses, but it would make my teeth hurt.


 




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