Why do they say the 50mm lens is a like a human eye? (continued)

jrtrent said:

aman74 said:

There was a post in the other thread where someone was talking about how the 50 feels "real", etc. That's fine if that's the photographers thoughts and approach, but I always get a kick out of it when people don't seem to embrace photography as an abstract art form. The reference Ansel Adams as pure when he knew this as well as anyone and said as much. Also, his darkroom work in today's equivalent would be considered seriously heavy PP.

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That may well have been me. I don't embrace photography as art at all (at least not my own), but as an aid to remember things (and as fun toys to play with!).

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Like I said, that's valid as well.

I guess I should clarify. I guess it's when people tout about how everything should be as natural as possible, whatever that means, and condemn others for their practices as if they are somehow impure. Meanwhile, right from the start it's an abstract image. People say a little PP is ok, but then who draws the line?

It's somehow more true to let a cameras jpeg engine make all the decisions rather than have the photog make every choice along the way to final output.

I didn't mean to slight you, I just went on a bit of a rant I guess.

Frank LoPriore said:

aman74 said:

Frank LoPriore said:

Actually, I'm the one who originally said tele lenses cause compression. Not sure why you don't think those two pictures demonstrate that?

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Umm, because they don't.

Frank LoPriore said:

The author even describes the picture taken with the tele as "perspective compression". No mention that I can see about moving and cropping. Both subjects appear to be the same size
but there is quite a difference in the apparent distance to the background.
--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

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Your actually explaining it to yourself and you still don't get it.

Sherwoodpetes recent couple of posts explain it perfectly. I don't have the patience he does. If you don't understand at this point I don't think there's much I can do about it. You seem determined to live in ignorance on this issue.

I think the concept is dead simple to understand. Why don't you go out in your backyard with a normal or a wide lens along with a tele and learn it on your own.

Stay in the SAME spot, pick a nice subject with a nice background aways back from your subject, take 2 pics, one with each lens and crop the wider lens to match the tele.

Seriously, I learned this 15 years in photography 101. It really is the ABC's of photography and this is getting ridiculous. More serious forums would be laughing their asses off about this one.

Edit to add this:

I'm sure this article was linked to and referenced but here's a snippet from LL:

"Exercise C

Take a photograph of the same scene, without moving your camera and tripod, with both a wide angle and a telephoto lens. When you return to your studio crop and enlarge the photograph taken with the wide angle lens so that you get the same composition as the image taken with the telephoto lens.

Compare the two telephoto images: the one created with a telephoto lens and the one created by cropping the wide angle view. You will not see any differences as far as composition and “compression” of the scene are concerned. "

Dead simple.

aman74 said:

Take the shot with a wide angle lens and then crop and the relationship between the subject and it's background will be the same as if you had used a long tele. Tele lenses cause no flattening, compressing, etc....

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When I first broke into wildlife photography I was shooting a colony of Cormorants on an island. The island was about 1/2 mile from where I was shooting. The shore looked about the same distance from the opposite side of the lake.

So, I wasn't really thinking, but when I got home and looked at the pictures, the opposite shore looked maybe 200 yards from the island. So on my mext trip, I wind up hiking three miles with my gear, to get to that spot - Well it was actually further away then my original location.

The perspective might be the same, but the magnification is not. In theory, since my rig at the time was 1600mm, the island from the original location appeared only 81 feet away, while the far shore was simply double that - 162 feet. But at these distances, that's compressed. And it appeared to be much closer to the shore.

Lesson learned.

Dave

aman74 said:

aman74 said:

I didn't realize people were actually debating whether tele lenses cause compression. As someone who shoots wildlife with an 800mm lens, and also takes shots of the same scenes with a 24mm lens, the answer is obvious on every shot.

Of course they do.

Dave

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Take the shot with a wide angle lens and then crop and the relationship between the subject and it's background will be the same as if you had used a long tele. Tele lenses cause no flattening, compressing, etc....

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Are you saying the background buildings are the same in that link? The subject is, for all practical purposes, the same size so cropping or moving back was most likely already done. So, moving back with the tele brought the buildings closer, or moving closer moved them further away. If cropping was used, the subject is the same, but the background is not. Makes sense to you?
--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

In that example the camera was moved.

I'm done with this one.

Frank LoPriore said:

Before this thread goes south again, allow me to explain my position fully. I have never stated that camera position does not effect perspective. Of course it does. But given the same camera position, focal length also effects perspective. To say, as some do, that focal length has no effect on perspective is incorrect.

--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

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Yes, I tend to agree. Consider these two shots:





The first is taken with an 18mm wideangle lens on 35mm film.

The second is merely a crop and enlargement from the centre of the first. The intention was to simulate the angle of view of a 50mm lens.

Now to my eyes, the second shot is beginning to show more of the character of a telephoto lens, though not to an extreme degree.

The point being, that both shots were taken from exactly the same spot (on the same piece of film!) yet the visual effect is clearly very different.

The purists will argue that the perspective is identical, and I agree it is, by definition, but nevertheless merely changing the angle of view has a strong influence on the image.

Regards,
Peter

sherwoodpete said:

http://books.google.com/books?id=wiaciWKK2xEC&lpg=PA62&dq=perspective%20compression&pg=PA62#v=onepage&q=perspective%20compression&f=false

Quote:

"The human eye has a fixed focal length and a fixed field of vision. Apparent perspective in the viewfinder can be altered by changing the focal length of the lens together with the distance of the camera from the subject. "

Note that here it is mentioned that two things are changed:

• focal length
• distance of camera from subject

There are those who say that only one of these factors is important - in some cases the first, in others the second, but I think it is fair to include both together as a more complete description of what is happening.

Regards,
Peter

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Yes, Peter, I agree, That is a fair statement. Thank you for being open minded. I admit I learned more about perspective.
--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

Between the original thread & this one, too many posts to go through, but after browsing several, I haven't seen the mathematical explanation:

It's based on a "standard viewing distance" for a print and assumes the viewer is looking at a print from a distance equal to the diagonal of the print. Obviously this doesn't work for small snaps (my eyes can't focus that close !)

If you photograph a scene with a lens whose FL == film/sensor diagonal, then print the shot, then view it at a viewing distance == print diagonal, the print occupies the same field of view that the original scene did. If you went back and stood in the exact same place you were when you took the shot and held the camera out in front of you (at 'standard viewing distance') then the print would "blend" into the scene.

When those assumptions are met, the 'magic' of a normal lens occurs; the print viewed at the right distance looks natural because the scene that it shows appears to your eyes as it would if you were looking at it from where the photographer stood.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

Frank LoPriore said:

To say, as some do, that focal length has no effect on perspective is incorrect.

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OK, I'll say it. Focal length has no effect on perspective

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

sherwoodpete said:

The purists will argue that the perspective is identical,

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If by 'purist' you mean someone who subscribes to the definition of the word perspective, sure

sherwoodpete said:

and I agree it is, by definition, but nevertheless merely changing the angle of view has a strong influence on the image.

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Of course. But let's not mix up perspective and FOV.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

Chato said:

I didn't realize people were actually debating whether tele lenses cause compression.

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I agree it's a silly debate ... I can't imagine why anyone would think that a telephoto lens causes compression !

Chato said:

As someone who shoots wildlife with an 800mm lens, and also takes shots of the same scenes with a 24mm lens, the answer is obvious on every shot.

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The answer should be obvious: that they do not ! But you seem to be confusing the cause of 'compression' in your images but ignoring some variables. Like subject distance.

'Telephoto compression' is real, but it's due to shooting distance that accompanies use of a telephoto lens. Telephoto compression can be obtained with a WA lens and sufficient cropping.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

I can see resistance is futile. I will concede the point as I have no acceptable proof to the contrary. Hopefully this will be sufficient to extricate myself from a discussion I am not qualified to be in. Peace.
--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

Dennis said:

sherwoodpete said:

The purists will argue that the perspective is identical,

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If by 'purist' you mean someone who subscribes to the definition of the word perspective, sure

Dennis said:

and I agree it is, by definition, but nevertheless merely changing the angle of view has a strong influence on the image.

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Of course. But let's not mix up perspective and FOV.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

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Some would hold the opinion that the camera position is the only influence on the perspective.

Imagine an infinitely long road, with monotonously similar buildings along each side. Add the constraint that the camera is aimed straight down the length of that road.

You could march up and down all day, but changing the camera position would have zero effect upon the image. However, changing the focal length would have a dramatic effect.

Regards,
Peter

Dennis said:

Telephoto compression can be obtained with a WA lens and sufficient cropping.

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Of course it can.

But what would the angle of view then be? I guess it's just possible it would no longer be WA.

Regards,
Peter

Dennis wrote:
snip

Dennis said:

When those assumptions are met, the 'magic' of a normal lens occurs; the print viewed at the right distance looks natural because the scene that it shows appears to your eyes as it would if you were looking at it from where the photographer stood.

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But the same thing happens with ANY f-length of lens, Dennis, not just with what people are pleased to call a "normal".

The print simply has to be held at the mathematically correct viewing distance for the print in question... which is given by the formula..

focal-length-of-lens-used multiplied by degree-of-linear-enlargement-in-print

Your example is just ONE of the examples that works. All other f-lengths work similarly... the prints are just held at different distances, that is, longer for long lenses, shorter for short ones...

..... [Oh! What a surprise!]

AS ALWAYS , it is the distance you view from that creates a perspective, not the bl00dy f-length of the lens you framed it with ...

...... as it is in viewing the subject, so it is in viewing the print.

Q: Does this mean that if you stand close enough to a wide angle print, the apparent 'distortion' will somehow disappear?

A: Hmmm... Tell you what, work it out for yourselves . You guys have had enough clues, now. :-(
--
Regards,
Baz

I am 'Looking for Henry Lee (could be Lea, or even Leigh) and despite going 'Hey round the corner', and looking 'behind the bush', I have not yet found him. If he survives, Henry is in his mid-60s, British, and quite the intellectual.

What is it all about? Well, something relating to a conversation we had in the pub 35 years ago has come to spectacular fruition, and I'd like him to know how right he was.

If you know somebody who could be this man, please put him in touch with me. Thank you.

sherwoodpete said:

Dennis said:

Telephoto compression can be obtained with a WA lens and sufficient cropping.

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Of course it can.

But what would the angle of view then be? I guess it's just possible it would no longer be WA.

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Nice try. The compression is there whether you crop or not. Take the WA image, print it huge, then stare at the center of it. There's no difference in the relationship between objects.

This is "The Earth Is Round" stuff here ... your shooting position affects perspective; FL does not. It's not debatable.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

Barrie Davis said:

Barrie Davis said:

When those assumptions are met, the 'magic' of a normal lens occurs; the print viewed at the right distance looks natural because the scene that it shows appears to your eyes as it would if you were looking at it from where the photographer stood.

Click to expand...

But the same thing happens with ANY f-length of lens, Dennis, not just with what people are pleased to call a "normal".

The print simply has to be held at the mathematically correct viewing distance for the print in question... which is given by the formula..

focal-length-of-lens-used multiplied by degree-of-linear-enlargement-in-print

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Sure, but those viewing distances are contrived to create the effect, whereas the viewing distance == print diagonal is supposed to be a sort of a standard used in art galleries, used by painters centuries ago; might even be the basis for DOF calculations; I'm not sure.

Anyway, you're of course free to ignore any such properties of the 'normal' by rejecting the 'standard viewing distance' argument; I'm just repeating an explanation I've read.

Barrie Davis said:

Your example is just ONE of the examples that works. All other f-lengths work similarly... the prints are just held at different distances, that is, longer for long lenses, shorter for short ones...

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Again, the standard lens works because there's a school of thought out there about what a standard viewing distance is that is NOT derived from this exercise, but that originated even before photography.

You might reject the standard viewing distance argument, but odds are people don't prefer to view images at a distance that 'works' for a 400mm lens or a 20mm lens.

Barrie Davis said:

AS ALWAYS , it is the distance you view from that creates a perspective, not the bl00dy f-length of the lens you framed it with ...

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Who are you telling this to ?

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

sherwoodpete said:

Some would hold the opinion that the camera position is the only influence on the perspective.

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Like some hold the opinion that the earth is round, not flat ?

sherwoodpete said:

Imagine an infinitely long road, with monotonously similar buildings along each side. Add the constraint that the camera is aimed straight down the length of that road.

Click to expand...

sherwoodpete said:

You could march up and down all day, but changing the camera position would have zero effect upon the image.

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Unless those building are infinitesimally small, it will certainly have an effect (unless you move in increments equal to the distance between buildings).

Further, the picture will appear to have no change in perspective, but only because the viewer cannot differentiate between objects.

It's an interesting thought exercise. And if I'm ever photographing on that road and subject to the constraints that I can only move in increments equal to the distance between buildings, have to stand in the center of the road (or at least maintain a fixed distance from the sides) and can only aim up & down the road, I'll acknowledge that changing my location along the road,can't affect perspective.

sherwoodpete said:

However, changing the focal length would have a dramatic effect.

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On the FOV, not on perspective.

• Dennis

--
Gallery at http://kingofthebeasts.smugmug.com

Dennis said:

On the FOV, not on perspective.

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Yep, that's the crux of it all. I thought Pete had it earlier in the thread and then he went off the reservation.

I'm sincerely surprised that this is even an issue.

It's nice of you Dennis and some other to make the effort to explain things for folks. I just feel it's falling on deaf ears.

Frank LoPriore said:

I can see resistance is futile. I will concede the point as I have no acceptable proof to the contrary. Hopefully this will be sufficient to extricate myself from a discussion I am not qualified to be in. Peace.
--
Frank
Please check out my galleries here
and http://www.pbase.com/fjlsolys

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Just take a deep breath and relax. Re-read the info given. I think it will soak in and then the next time the subject comes up you will be qualified to be in it and you'll be on the right side of the fence.

You have the means to achieve the proof. Why not go shoot some tests. It would be a good exercice and you'll learn something.

I'm not trying to be a smartass either. I'd genuinely like people to be able to see that it's all pretty simple. If you're able to figure it out I promise you'll have a moment where you realize your side of the argument is like someone said "saying the earth is flat".

Dennis laid it very clearly. I believe Barrie did as well. There's the LL link, etc... 2+2 is 4.