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### AuthorTopic: when is wide too wide?  (Read 63824 times)

#### Slobodan Blagojevic

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##### Re: when is wide too wide?
« Reply #80 on: May 21, 2013, 12:21:39 PM »

Exactly. That's why I don't really understand what Ray wants to point out...

Hmmm... not sure about the "exactly" part. If I understood correctly, Rays wants to point out that your proposed test proves only that "the same" is "the same," i.e., proves nothing.

#### torger

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##### Re: when is wide too wide?
« Reply #81 on: May 21, 2013, 12:59:50 PM »

Hmmm... not sure about the "exactly" part. If I understood correctly, Rays wants to point out that your proposed test proves only that "the same" is "the same," i.e., proves nothing.

It's a bit confusing, but I guess the reason is some misunderstandings. Reading through some of the posts earlier in the thread it seems like Ray understands all this, so I don't really know what the discussion is about.

There seems to be no disagreement in how things work, just hair-splitting on exactly how to use the word "perspective", and about the practicality of cropping in post. Of course cropping a 14mm lens to a 200mm framing is inpractical because of lost resolution, and it seems like Ray is using that as a base for saying that a 50 and 80mm lens can be made equivalent through cropping but not a 14 and 200, and throw in some "perspective" into that and confusion begins.
« Last Edit: May 21, 2013, 01:03:14 PM by torger »
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #82 on: May 21, 2013, 04:28:30 PM »

Cropping from the center is of course important to achieve the same effect, if cropping off-center one will instead simulate a shifted lens, and shift is as we know often used for perspective control in architecture photography.

What you correct with a T/S lens is the apparent perspective distortion of the lens.  The perspective - spatial relationships - remains the same.

The reason to crop from the centre is because that's where the two lenses can be seen to have the same angle of view and the same subject matter for comparison.  Crop from the edge of a WA frame and there'll be nothing in the tele frame to compare to.
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#### Ray

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##### Re: when is wide too wide?
« Reply #83 on: May 22, 2013, 08:24:33 PM »

Ray,

To take the discussion further you need to post images that proves your point. Here's an experiment for you:

1. Mount the camera on a tripod, point it at some area with geometric objects, like a playground or similar
2. Shoot two photographs with one wide angle and one longer focal length (or use a zoom). Do not move the camera or change its direction.
3. Make sure that you apply distortion correction in your raw converter so the lenses render as close as possible to perfect rectilinear
4. Crop the wide angle so it has the exact same FOV as the longer focal length
5. Compare.

If I understand you correctly you claim that there will be some more difference apart from lower resolution. I have not been able to understand what difference that would be from all your long posts. Can you describe in a short way what you mean the difference between cropping a wider and using a longer focal length would be?

I can give you a lead: the experiment above will show that there is no difference to be found.

Torger, I have posted images relating to this issue in other threads. I own a Nikkor 14-24 so I'm very familiar with the effect of moderately distant objects, such as mountains in the background, appearing really tiny in relation to the much larger objects in the foreground  which seem closer to their normal size, or the size one might expect them to be.

I also know very well that cropping a wide angle shot to the same FoV as a shot from a longer lens, from the same position, results in images with the same perspective, provided that resolution is sufficient for one to be able to recognize the elements in the cropped image.

For me, this issue is about describing a phenomenon or image characteristic clearly, precisely and logically so that the statement holds true in all situations. If there are exceptions, then the theory cannot be claimed to be true, in the absence of other explanations for the anomalies.

All I'm asking is for some bright spark to provide the explanation for these obvious exceptions and inconsistencies, as in the following example which highlights the problem and perhaps even proves that people like JJJ and Bart are wrong on this issue. I never accuse people of being wrong unless I'm also able to provide reasons and evidence for their being wrong.

In view of the categorical statement from JJJ that "Cropping has zero effect on perspective, nor does print/sensor size or viewing distance and the biggest myth of all, focal length", then why have you required the act of cropping, in procedure # 4 above, in order to demonstrate that cropping has no effect on perspective?

If two images taken with different focal lengths of lens appear to have the same perspective, and after cropping one of the images, the perspective is still the same, then that would demonstrate that cropping has no effect on perspective, provided one repeated the cropping a few times with different images just to be sure there were no exceptions.

However, if all images taken from the same position, without exception, appear to have the same perspective, whatever focal lengths of lens was used, then what is the purpose of cropping, in your experiment as described above? Are you with me so far?

Is it reasonable for me to assume that you recognise that the image from the wider-angle shot only appears to have a different perspective and that you have cropped the wider-angle shot in order to demonstrate that this apparent difference is a mere illusion?

Now this is what I suspect is going on here.  People like JJJ and Bart, and others, are trying to claim that images taken with wide-angle lenses only appear to have a different perspective as a result of various lens distortions, and that cropping removes such distortions to reveal the true perspective which is determined only by lens position.

let's examine this argument to see if it makes sense. It's true that wide-angle lenses tend to produce a type of distortion known as Volume Anamorphosis, which editing programs from DXO can correct reasonably well, and it is now commonplace for image editing programs such as ACR and Lightroom to correct for various types of lens distortions, provided there's a profile available for the lens.

But let's take this a step further and claim that despite such distortion corrections in programs from DXO and Adobe, the images from the wider-angle lenses are still distorted and this is the only reason why the wider-angle shots appear to have a different perspective.
If this statement is true, then it would follow that in any comparison of shots taken with different focal lengths of lens, the longer focal length would always provide the truer perspective. In other words, the shot from the 14mm lens appears to have a different perspective to the same scene  shot with a 35mm lens, only because the 14mm lens is plagued by uncorrectable distortions. Also. we would have to claim that the shot from the 35mm lens compared with another shot from an 85mm lens only appears to have a different perspective because 35mm lenses are inherently more prone to distortions than 85mm lenses.

We could apply the same comparisons of 85mm lenses with 200mm lenses, 200mm with 400mm lenses and 400mm lenses with 1,000mm lenses and so on. With each comparison between longer and longer focal lengths of lenses, we would eventually arrive at the situation where the longest focal length of lens that it is possible to manufacture would provide the truest perspective and that any differences in perspective that may appear in images taken with shorter focal lengths, are merely illusions.

Is this what you believe, Torger?

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#### torger

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##### Re: when is wide too wide?
« Reply #84 on: May 23, 2013, 02:27:16 AM »

It seems to me that you are describing self-explanatory things like "a wider lens has a wider FoV and therefore perspective appears different"?

The most natural-looking perspective is typically something whose focal length is close to the diagonal of the sensor, the appearance becomes close to what our eyes experience. As soon as you crop you effectively lengthen focal length and get a more compressed perspective in the image, but you also see less.

When people say that cropping has no effect on perspective what they mean is that no angles or relations change in the scene, ie no magic lightbending happens. They don't mean that the appearance of the perspective of final image does not change, because it does of course. It's a confusion around how people use the word "perspective". You seem to use it in a painter's way, the apparent perspective in the final image, while those other guys use it as the eye see it when at the actual scene (ie "to get a different perspective you need to move to a different view point"). Partly in the discussion it seems like there are some deliberate misunderstandings and misinterpretations which makes it very difficult to move the discussion forward.

Viewing distance of the image can change the appearance too, if you stand very far away from a tele shot it may look more natural and less compressed, as what you see is so small it could be a cutout of what the eye sees. Likewise standing very close to a large print of a wide angle shot can make it appear more natural, as long as you look at the center and don't turn your head. But in practice viewing distance is rather irrelevant I think as one nearly always watch an image at a typical distance and/or the trained eye has learnt to concentrate on what's in the frame only, ie a wide angle will always have the wide angle perspective look and the tele will have that compressed look.
« Last Edit: May 23, 2013, 02:35:18 AM by torger »
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#### BartvanderWolf

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##### Re: when is wide too wide?
« Reply #85 on: May 23, 2013, 05:10:39 AM »

Now this is what I suspect is going on here.  People like JJJ and Bart, and others, are trying to claim that images taken with wide-angle lenses only appear to have a different perspective as a result of various lens distortions, ...

Hi Ray,

You suspect wrong.

Re-read the posts that were linked to before, and you'll see that lens distortions play no role in linear perspective, they are merely aberrations.

We're simply dealing with an apparent perspective distortion caused by projection on a flat plane, and from usually viewing it from the wrong position/distance. If the flat plane projection were to be viewed from the proportionally correct position, the perspective would look exactly the same at it did in real life.

Since, for obvious reasons, we usually do not adjust our viewing position to achieve 'correct' perspective, prints may exhibit e.g. a seemingly wide-angle look or a compressed tele-lens look, and a good photographer can use that as a compositional element.

This article on Wikipedia opens with the following overview:

Quote from: Wikipedia
Linear perspective always works by representing the light that passes from a scene through an imaginary rectangle (the painting), to the viewer's eye. It is similar to a viewer looking through a window and painting what is seen directly onto the windowpane. If viewed from the same spot as the windowpane was painted, the painted image would be identical to what was seen through the unpainted window.

"torger" summed it up pretty well in the preceding post, so I see no further need to keep repeating what has been said before by myself and others.

Cheers,
Bart
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#### jjj

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##### Re: when is wide too wide?
« Reply #86 on: May 23, 2013, 08:27:41 AM »

All I'm asking is for some bright spark to provide the explanation for these obvious exceptions and inconsistencies, as in the following example which highlights the problem and perhaps even proves that people like JJJ and Bart are wrong on this issue. I never accuse people of being wrong unless I'm also able to provide reasons and evidence for their being wrong.

In view of the categorical statement from JJJ that "Cropping has zero effect on perspective, nor does print/sensor size or viewing distance and the biggest myth of all, focal length", then why have you required the act of cropping, in procedure # 4 above, in order to demonstrate that cropping has no effect on perspective?

If two images taken with different focal lengths of lens appear to have the same perspective, and after cropping one of the images, the perspective is still the same, then that would demonstrate that cropping has no effect on perspective, provided one repeated the cropping a few times with different images just to be sure there were no exceptions.

However, if all images taken from the same position, without exception, appear to have the same perspective, whatever focal lengths of lens was used, then what is the purpose of cropping, in your experiment as described above? Are you with me so far?
Grief Ray are you trying to convince everyone you have lost your marbles? Cropping is done so you can [easily] compare same sized image subjects side by side, thus proving that it is position, not lens choice that affects perspective. The only difference then is image quality.

Quote
Now this is what I suspect is going on here.  People like JJJ and Bart, and others, are trying to claim that images taken with wide-angle lenses only appear to have a different perspective as a result of various lens distortions, and that cropping removes such distortions to reveal the true perspective which is determined only by lens position.
You assume incorrectly. So everything else you said about this daft assumption is irrelevant.
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#### Ray

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##### Re: when is wide too wide?
« Reply #87 on: May 23, 2013, 12:52:02 PM »

Hi Ray,

You suspect wrong.

Re-read the posts that were linked to before, and you'll see that lens distortions play no role in linear perspective, they are merely aberrations.

Good! I'm glad to hear it. We can now rule that out as a possible explanation as to why changing focal length of lens appears to change perspective.

Quote
We're simply dealing with an apparent perspective distortion caused by projection on a flat plane, and from usually viewing it from the wrong position/distance. If the flat plane projection were to be viewed from the proportionally correct position, the perspective would look exactly the same at it did in real life.

Linear perspective always works by representing the light that passes from a scene through an imaginary rectangle (the painting), to the viewer's eye. It is similar to a viewer looking through a window and painting what is seen directly onto the windowpane. If viewed from the same spot as the windowpane was painted, the painted image would be identical to what was seen through the unpainted window.

Good analogy, Bart. I accept that as being reasonable and possibly correct. But we should inform JJJ because he seems to be under the misapprehension that viewing distance of print is irrelevant to perspective. This is what he wrote in reply#52. "Cropping has zero effect on perspective, nor does print/sensor size or viewing distance and the biggest myth of all, focal length."

I can imagine if one makes a huge print of a very wide-angle shot that appears to make the mountains in the background more distant than they did to the naked eye when the shot was taken, one can at least partially correct for that perspective distortion by viewing the print from a very close distance so that the mountains then appear to be at the correct distance within the over all scene. Unfortunately, I suspect that from such a close viewing distance required, one would unavoidably create other distortions when viewing at an extreme angle other  elements in the image that exist towards the edges of the print.

To correct for this one would probably have to mount the print on a concave surface. Unfortunately again, one cannot so easily do the opposite of viewing up close, that is viewing a small print from a long telephoto shot from a great distance. A long telephoto shot may result in a distant speck, hardly discernible by the naked eye, appearing as a large bird on the print, so close that one could reach out and grab it if it were real.

I understand that the rules of perspective were formulated before the camera was invented, and such rules seem to apply to perceptions by the unaided human eye. Instead of painting the scene directly onto the window, as viewed through a particular size of window, if we were to photograph the view through the window, standing in the same spot as the painter and using different focal lengths of lenses to take a number of shots from the same position, then make prints the same size as the window and paste them onto the window, we would have a lot of different perspective effects instead of the one effect that the painter sees.

Quote
"torger" summed it up pretty well in the preceding post, so I see no further need to keep repeating what has been said before by myself and others.

Maybe, but still a few mistakes, Bart. I'm doing my best to dispel muddled thinking on this issue, but it's not easy.
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#### Ray

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##### Re: when is wide too wide?
« Reply #88 on: May 23, 2013, 01:13:31 PM »

Grief Ray are you trying to convince everyone you have lost your marbles? Cropping is done so you can [easily] compare same sized image subjects side by side, thus proving that it is position, not lens choice that affects perspective. The only difference then is image quality.

Good grief, JJJ. Is that how you cheat? You compare two shots taken with different 'effective' focal lengths, and to make it easy, you crop the wider-angle shot to the same FoV as the narrow angle-shot so that no-one can tell the difference. Are you sure that's ethical?

By the way, the image quality doesn't always have to be different. That depends on lens quality and sensor pixel density. To get people really confused so they can't see any difference at all between the two images, you could use a D700 with a lower quality, longer focal length and a D800 with a better quality shorter lens so that both images, after cropping the D800 shot, have the same pixel count and resolution.
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#### Ray

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##### Re: when is wide too wide?
« Reply #89 on: May 23, 2013, 01:49:29 PM »

It seems to me that you are describing self-explanatory things like "a wider lens has a wider FoV and therefore perspective appears different"?

That a wider lens has a wider FoV is self-explanatory, but that explanation doesn't include the reason why perspective appears different. In fact, what I consider as very self-explanatory is the notion that a wide-angle shot after cropping to the same FoV as a narrow angle shot will then look the same, provided both shots were taken from the same position. Or as Slobodan wrote, "Ray wants to point out that your proposed test proves only that "the same" is "the same," i.e., proves nothing", and Slobodan is often quite perceptive.

Quote
The most natural-looking perspective is typically something whose focal length is close to the diagonal of the sensor, the appearance becomes close to what our eyes experience. As soon as you crop you effectively lengthen focal length and get a more compressed perspective in the image, but you also see less.

By seeing less, do you mean you see fewer elements within the image; those things that Bob Fisher denies have any relevance to perspective?

Quote
When people say that cropping has no effect on perspective what they mean is that no angles or relations change in the scene, ie no magic lightbending happens. They don't mean that the appearance of the perspective of final image does not change, because it does of course.

If that's what they mean, they are of course at least partly right and partly in error. But notice that I don't claim people are wrong without providing detailed and helpful information on precisely why they are wrong. They are right in thinking that no magic light-bending occurs as a result of cropping. One is not able to see around corners without changing position.

However, it seems clear to me, almost self-explanatory, that some spatial relationships do change as a result of cropping. Not all change of course. Only the relationships of those elements that remain after cropping, with those elements in the wider-angle shot that have been cropped out, change.

I've mentioned very clearly, earlier in the thread, that I'm discussing the perspective as it appears in the final image. This is a photographic forum. Lens focal length and concepts of cropping apply only to photographic images, not paintings. But I'm glad you agree that the appearance of perspective does change with cropping.

Quote
It's a confusion around how people use the word "perspective". You seem to use it in a painter's way, the apparent perspective in the final image, while those other guys use it as the eye see it when at the actual scene (ie "to get a different perspective you need to move to a different view point").

I've never, ever argued that moving to a different viewpoint does not provide a different perspective. I'm not only using  perspective in a painter's way, but in a way that I assume most people see things whether they are painters or photographers, or neither.

Quote
Partly in the discussion it seems like there are some deliberate misunderstandings and misinterpretations which makes it very difficult to move the discussion forward.

I assure you there are no deliberate misunderstandings on my part. I believe that some of the confusion may be due to some people interpreting perspective too narrowly, as though it were a single thing, either/or, black or white.
I interpret perspective as an impression, not only of the relative positions of all the objects in the scene, but their relative size and an impression of their relative distance to each other, and distance from the viewer as determined by their relative size.

Quote
Viewing distance of the image can change the appearance too, if you stand very far away from a tele shot it may look more natural and less compressed, as what you see is so small it could be a cutout of what the eye sees. Likewise standing very close to a large print of a wide angle shot can make it appear more natural, as long as you look at the center and don't turn your head.

Absolutely true! You should tell that to JJJ.

Quote
But in practice viewing distance is rather irrelevant I think as one nearly always watch an image at a typical distance and/or the trained eye has learnt to concentrate on what's in the frame only, ie a wide angle will always have the wide angle perspective look and the tele will have that compressed look.

I find that what mainly influences my viewing distance is the size of the image or print. I tend to peer closely at small prints on the wall, and stand back from large prints, whatever the focal length of lens that was used for the shot, so yes, I agree that adjusting viewing distance to correct for perspective distortion is not something that most viewers would attempt or bother to do.

However, I would maintain, if it is true that the use of a particular focal length of lens on a particular camera results in an unavoidable perspective distortion that requires the viewer to adjust his viewing distance to the image in order to correct that distortion, or at least partially correct it, then logically one surely has to admit that a change in focal length can affect the perspective in the final image or print.

I rest my case.
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #90 on: May 23, 2013, 02:12:02 PM »

I rest my case.

Good.  Get all the rest  you can.  Because I don't think even you know what you're talking about any longer.  Not that you ever did, at least in this regard.
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#### Ray

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##### Re: when is wide too wide?
« Reply #91 on: May 23, 2013, 11:15:20 PM »

Good.  Get all the rest  you can.  Because I don't think even you know what you're talking about any longer.  Not that you ever did, at least in this regard.

What I think is far more likely, Bob, is that it is you who do not understand what I am talking about, not me.
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#### Ray

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##### Re: when is wide too wide?
« Reply #92 on: May 23, 2013, 11:46:30 PM »

I can only conclude that some of you guys are, shall we say, logically challenged, to be polite, which is why I keep bringing up the Alice in Wonderland scenario. Your arguments sometimes remind me of  the amusing absurdities in that book.

For example, I write:
"Now this is what I suspect is going on here. People like JJJ and Bart, and others, are trying to claim that images taken with wide-angle lenses only appear to have a different perspective as a result of various lens distortions, and that cropping removes such distortions to reveal the true perspective which is determined only by lens position."

Notice that I am not declaring that I believe that lens distortions and aberrations are the cause of perspective appearing different with different FLs of lens. I am merely speculating on the possible reasons why some people do.

Now Bart responds with the flat statement, "You assume incorrectly", thus speaking on behalf of all those who are of the opinion that choice of lens has no bearing on perspective. Notice in my original statement, I used the phrase People like JJJ and Bart, and others. I wasn't referring only to Bart.

In my opinion, Bart could have more correctly responded along the lines, "I can only speak for myself and I can assure you that I do not believe that lens distortions contribute to an apparent difference in perspective."

Now, you might think this is just nitpicking, but I find it revealing because JJJ immediately jumps in and declares if I'm wrong on one point I must be wrong on all points. He writes: "You assume incorrectly. So everything else you said about this daft assumption is irrelevant", thus demonstrating his own incapacity for logical thinking.

This is all the more ironic because Bart is speaking on behalf of JJJ who has previously declared that viewing distance to the resulting image has no bearing on perspective, whereas Bart considers that viewing distance to the resulting image is instrumental in correcting the apparent distortion of perspective that presumably varies with the changing focal length of lens, requiring a print from a wide-angle lens to be made large and viewed from close up, and a print from a telephoto lens to be made small and viewed from a proportionally greater distance.

I have always made it clear in these discussions that I am referring to perspective as seen in a photographic image.

Now that I'm fully rested, I'll expand upon the point that Bart has made in relation to his explanation for this apparent change in perspective, hoping that he can clarify matters a bit more. He writes: "We're simply dealing with an apparent perspective distortion caused by projection on a flat plane, and from usually viewing it from the wrong position/distance."

I'm not sure how simple that is if we have to adjust viewing distance for every individual print in accordance with both print size and 'equivalent' focal length of lens used, with the almost infinite number of variables implied. That sounds very complicated to me.

If the perspective distortion caused by the projection of a 3-dimensional view onto a flat plane were a fixed quantity that varied only in proportion to print size, then that would be simple.

I can only conclude, in accordance with very basic laws of logic, that focal length and cropping, or effective focal length, can change our perception of perspective in the final print. What further proof does one need?

By the way, I'm using very basic laws of logic which I assume we are all capable of understanding. If A=B and B=C, then it follows logically that A also equals C. Would anyone care to dispute that?
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #93 on: May 24, 2013, 07:29:30 AM »

"Perception" of perspective is a different matter, Ray.  It's like 'apparent' perspective distortion.  It doesn't change the fact that linear perspective is solely a function of distance to subject.  It's like saying the road looks like it's converging in the distance but when you get to that spot it isn't, but it then looks like it is further along.
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#### Ray

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##### Re: when is wide too wide?
« Reply #94 on: May 24, 2013, 08:51:36 AM »

Bob,
This is a photographic forum, not a mathematics or geometry forum.

A photograph is usually a 2-dimensional representation, on a flat surface, of a particular scene that the photographer captured with camera and lens of choice.

Linear perspective is a scientific theory attributed to the architect Fillipo Brunelleschi, sometime around the year 1413.

Now don't tell me, whilst I've been discussing the perception of perspective as it appears on photographic images, all along you've been discussing Brunelleschi's scientific theory and never once mentioned it.
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #95 on: May 24, 2013, 09:12:22 AM »

Bob,
This is a photographic forum, not a mathematics or geometry forum.

Tell that to the members who go on for pages and pages and pages about the minutiae of pixel density or examine 500% enlargements for image noise.

Quote
A photograph is usually a 2-dimensional representation, on a flat surface, of a particular scene that the photographer captured with camera and lens of choice.

That's what a photograph is?  [slapping hand to forehead]

Quote
Linear perspective is a scientific theory attributed to the architect Fillipo Brunelleschi, sometime around the year 1413.

Now don't tell me, whilst I've been discussing the perception of perspective as it appears on photographic images, all along you've been discussing Brunelleschi's scientific theory and never once mentioned it.

I'm using the same term Bart (and I think JJJ) used.  You can obfuscate all you want.  You're wrong.  You've always been wrong on this and if you persist in the silliness you've been engaging in up till now you'll continue to be wrong.

I'll admit to having been hard headed in a few discussions in the past where my thought process was incorrect.  But in the end even I came around to the right answer.
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#### Ray

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##### Re: when is wide too wide?
« Reply #96 on: May 25, 2013, 01:56:25 AM »

I'm using the same term Bart (and I think JJJ) used.  You can obfuscate all you want.  You're wrong.  You've always been wrong on this and if you persist in the silliness you've been engaging in up till now you'll continue to be wrong.

Bob,
Anyone can tell anyone he is wrong. It means nothing unless you can explain why a person is wrong. If the explanation is satisfactory the person who is wrong on any particular issue  may change his way of thinking. If the explanation is either absent or unsatisfactory, only a fool would change his way of thinking on that basis.

I have made it very clear from the start that I am talking about the appearance of perspective in photographic images.

I have always made a clear distinction between the perspective as seen in a real 3-dimensional scene by the human eye, and the representation of that same scene in a photographic image. I've mentioned this several times in this thread.

I understand completely that light, as relfected from the objects we see, generally travels in a straight line, except when it's diffracted for whatever reason. If an object is fully or partially obscured by another object which is situated in front of it, then no matter what lens you use with your camera, no matter what you ate for breakfast, no matter what clothes you happen to be wearing, that object that is further away will remain obscured in the real scene, unless one changes one's viewing position, or unless the objects move of their own accord.

Furthermore, if one is able to capture those particular objects with a camera, and present only those objects, and nothing but those objects, in a photographic image, then the perspective of those particular objects will not change whatever the focal length of lens used.

This is what is being demonstrated when people crop the wider shot to the same FoV as the narrower shot. They are demonstrating that perspective is the same if all the objects represented in the photo are the same, and provided the shots were also taken from the same position.

This is an important principle in photography because it demonstrates something of practical significance known as 'focal length equivalence'. Focal length equivalence, or effective focal length, is always a particular combination of lens focal length and cropping. All photographs without exception are crops. Whether such cropping is done in-camera or during post-processing is immaterial regards effective focal length.

The point I've always made regarding this issue is that a wider lens captures more objects than a narrower lens, and the presence of those additional objects in the wide-angle shot changes the perspective of those fewer objects, seen as a whole in the narrower or cropped shot. Without cropping, those fewer objects would be seen in a different context. They would be surrounded by other elements which create a different perspective with regard to relative distances.

This is why I think it is a scientifically fraudulent practice to crop a wide-angle shot to the same FoV as a telephoto shot, in order to demonstrate that perspective is the same whatever the focal length. It's equivalent to destroying evidence in order to maintain a falsehood.
« Last Edit: May 25, 2013, 02:01:19 AM by Ray »
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #97 on: May 25, 2013, 07:11:24 AM »

Tired of reading.
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#### Wim van Velzen

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##### Re: when is wide too wide?
« Reply #98 on: May 25, 2013, 04:43:24 PM »

Original poster here. Shall I change the subject title to: 'when is much too much?'? :-)
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#### RFPhotography

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##### Re: when is wide too wide?
« Reply #99 on: May 25, 2013, 07:04:58 PM »

Original poster here. Shall I change the subject title to: 'when is much too much?'? :-)

Way past that.
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