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#21
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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