How your lens selection controls portrait outcome

[J-see]

That's three times you've mentioned Cambridge here, which is the most that I can forgive you for. Some of it is OK, but I am not a fan, so I cringe.There are other things, you ought to see their gamma page, they actually imagine gamma was done for the human eye. How soon we forget.

Right, there is no telephoto perspective. It shows a larger subject of course (magnification and cropping, which we can easily just do later, except for pixel count), but the spatial relations are unchanged ,either way we do it. Perspective is only because of where we stand, due to what we see when we stand there, which any lens will capture there. We can speak of telephoto compression, but which is only true in a few special cases, depending on where we stand. The opposite is true if we stand other places. It's not about the lens. It's about where we stand. Why is that difficult for you?

Me thinks there's a whole lot of different perspectives going on in those shots.

 

[WayneF]

View attachment 203096

Me thinks there's a whole lot of different perspectives going on in those shots.

Damn, I guess we are starting all over. OK, I'm game.

Yes, of course several different perspectives because the photographer is choosing many different places to stand (to get same image size). Where we stand determines perspective. Not the lens. You might read the top of the thread.

Perspective is that view we see when we stand there, in that spot.
Any lens will capture that view, from there in that spot.
How hard is that?

If you consider perspective as depending upon a relation between the subject and its background, then a wide-angle can never reproduce a telephoto shot and vice versa.

I had decided to let it go by, but now that you're here, of course I just showed here that there is no perspective difference between 24 and 120 mm... IF we stand in the same place. I assumed by "reproduce", you only meant pixel count, which is a difference in cropping, but the way the image perspective looks is the same if we stand in the same place, regardless of lens.

​

 

[J-see]

Let's first come to an agreement about perspective. We use a cube to make things simple.



If I had taken this shot (cube - white background) it would not matter where I stood or which lens I used to calculate the perspective of this shot. I simply follow the lines until their vanishing points and I got the perspective. That's all there is to it.

And here background compression comes into play. Because the longer the focal length, the closer (or bigger) the background looks, those same perspective angles will start to differ more and more. When I use a 14mm and shoot the cube it'll appear distorted while when shooting it at 600mm it'll almost look straight. That's what compression does.

Because of this, my perspective (if visible in a shot) will always be affected by focal length regardless of where I am standing during the shot. Of course under the assumption the actual subject of the shot itself remains identical within each shot (size-wise).

 

[J-see]

BTW: when shooting portraits with wide-angle lenses, the distortion is not that people have big noses. The actual distortion is them having small heads. That's compression at work; or better the lack thereof.

It's this lack of compression that "forces" us to use longer lenses for decent portraiture.

 

[WayneF]

Let's first come to an agreement about perspective. We use a cube to make things simple.

If I had taken this shot (cube - white background) it would not matter where I stood or which lens I used to calculate the perspective of this shot. I simply follow the lines until their vanishing points and I got the perspective. That's all there is to it.

No, let's not. I doubt many of us actually take photos of graphics vanishing points.

Let's discuss the first pictures you posted at top of this page, of the girl in front of the building. Must have been some purpose for it too?

The perspective there is the constant height of the girl, and the variable height of the building. About how the building is made to look.

400 mm lens FX, I'd guess camera was 100 feet from the girl.

24 mm lens, camera maybe 6 feet from the girl.

That is going to change perspective, don't you think?

So of course you will see greatly different views in all those different locations there. And whatever lens will capture each view, from wherever you were standing.

And every distance was designed to keep the height of the girl constant.

But if you stand in the same one place for every focal length, and then crop results as necessary to see the same view in all, then you will see the same perspective view in all, the same building and girl heights, in all of them, any and all focal lengths (because you are standing in the same place for all - perspective does not change with any lens). Other than pixel count (which will suffer), their appearance will all be indistinguishable if you cropped well. Perspective is NOT about the lens.

Agreed that procedure is probably not a useful goal, except that it strongly makes the obvious point that perspective is NOT about the lens. It makes it dumb to argue that the lens causes perspective. Obviously it does not.

We could argue that the lens does make it desirable to stand in different places. And I would agree, the pictures desperately need the 100 foot and the 6 foot distances. But in the discussion about what causes perspective, perspective is only about where we choose to stand. It is not about the lens.

Perspective is the view you see when you stand in a certain spot. Any lens captures that view faithfully. It can do nothing else.

Because of this, my perspective (if visible in a shot) will always be affected by focal length regardless of where I am standing during the shot. Of course under the assumption the actual subject of the shot itself remains identical within each shot (size-wise).

No, that assumption is bogus for purposes here. Any perspective differences will strictly be due to where you choose to stand (to cause that constant subject size). It is NOT about the lens. Where you choose to stand may be about the lens, but perspective is only about where you choose to stand. Perspective is not about why you choose to stand there, but of course, we could choose where we stand for certain perspective goals.

Stand at a different distance with the SAME lens, and you will get a different perspective. Or stand at the same place with a different lens, and you will get the same perspective. It is about where you stand, not the lens.

I would argue the lens is only chosen to frame the subject. I know your preferred assumption would argue the lens could be chosen to permit the distance that gives the perspective we want, but that is my argument too, perspective is only about where we stand.

If you want to show evidence otherwise, the first step is to maintain a constant camera location, to rule out the effect of where you stand. But of course, you cannot, because where you stand is the only factor affecting perspective.

We see the view that we see when we stand there.

 

[J-see]

If you want to believe the perspective of a shot has nothing to do with vanishing points, be my guest.

If vanishing points are too "hypothetical" for photographers (about all landscape and architecture photography is based upon it), I assume shooting identical shots at relative positions using hypothetical lenses and sensors in order to crop to identical proportions is more "real world" to them.

I can't even make sense of the "where you stand" argument.

Take a baseball, put it on a table and shoot it with a 14mm at closest distance. Now you take a 600mm and reproduce that shot. You can stand wherever you desire to take the exact same shot with the exact same perspective distortion.

I can easily shoot a portrait in front of a building with my 600mm that has only one vanishing point but when going shorter in focal length, more of the building comes into the scene and it shifts from a one point to two or even three if I go short enough.

Those differences in perspective simply can not be accomplished with another focal length while maintaining the same subject magnification.

 

[Stoshowicz]

That's three times you've mentioned Cambridge here, which is the most that I can forgive you for. Some of it is OK, but I am not a fan, so I cringe.There are other things, you ought to see their gamma page, they actually imagine gamma was done for the human eye. How soon we forget.

Right, there is no telephoto perspective. It shows a larger subject of course (magnification and cropping, which we can easily just do later, except for pixel count), but the spatial relations are unchanged ,either way we do it. Perspective is only because of where we stand, due to what we see when we stand there, which any lens will capture there. We can speak of telephoto compression, but which is only true in a few special cases, depending on where we stand. The opposite is true if we stand other places. It's not about the lens. It's about where we stand. Why is that difficult for you?

If speaking of any so called "equivalent focal length", that is purely because of the smaller sensors cropping the image. Assuming same lens, the lens remains exactly the same lens, zero telephoto effect, but when we have to enlarge the cropped image more (because it is smaller), then we see a larger result view as if from a larger sensor with a longer lens (but the small one is necessarily enlarged more). All that happened was the smaller sensor cropped the image. If we stand in the same place, perspective remains the same either way. We are not required to stand in the same place, but perspective remains to be about where we do stand. Not due to the lens.



I wish you wouldn't say that because I'm not agreeing that we agree. Macro being so close does NOT cause extreme perspective effects. It is relative, ratio of near subject to far subject. We probably could assign a number to it, except there are a few planes. Macro is just the same percentage thing, already addressed.



Of course different lenses can cause many differences, that's why we choose them. But perspective is not one of those lens properties. Where we stand determines perspective. The lens might influence where we want to stand, but perspective is determined by where we choose to stand.

You realize we are just spinning wheels here? No added substance.

Its Not difficult for me! I agree entirely on the physics or optics which you are describing, Im just saying that the word perspective is used by people in a way which is not the same as your more specific esoteric use of the word ,, which is confusing to the neophyte. I promise I wont mention CiC again. Theres plenty of fish in the sea.

 

[WayneF]

If you want to believe the perspective of a shot has nothing to do with vanishing points, be my guest.

If vanishing points are too "hypothetical" for photographers (about all landscape and architecture photography is based upon it), I assume shooting identical shots at relative positions using hypothetical lenses and sensors in order to crop to identical proportions is more "real world" to them.

Not hypothetical at all, but more necessarily applicable to painting than photos. I do understand vanishing points, but I'm wondering if you do, why you would bring that cube up here in this discussion? Properties of your cube are real, but simply a distraction here, in the following sense: The photos you showed (of girl and building) are of course flat onto the building, not showing how the line of the building (or anything) recedes towards any horizontal vanishing points that you instead want to discuss somehow, This photo is a much simpler case, of simple near and far subjects, present in most photos (other than of flat documents maybe). The pictures you posted have no horizontal width or angles to show vanishing points (as you want to discuss with your cube.)

The simple vanishing point present in all photos is directly in front of the camera, on lens axis, receding into that distant frontal point.

I'm trying to get the subject back onto photography, the discussion subject should be the actual photos that show perspective.

The photo case is simpler than graphic painters face, just about apparent size differences, front to back, and side to side, up and down, apparent size dimensions due to distance. That is our photo perspective. It is pretty much just simple similar triangles, receding into the background. I am calling that perspective, because since we are not enrolled in elementary drawing classes, that is what we have. We are not creating a building on paper as we wish, we can only stand in front of it with our camera. The camera (with any lens) records what we see when we stand there. If we wish to see a different perspective, we can only stand someplace else. This is extremely obvious, not difficult, just forget your cube and think for a second.

I can't even make sense of the "where you stand" argument.

Take a baseball, put it on a table and shoot it with a 14mm at closest distance. Now you take a 600mm and reproduce that shot. You can stand wherever you desire to take the exact same shot with the exact same perspective distortion.

It does seem that you can't, but OK, I will call your statement. Lets see your baseball picture, standing in different places and showing "the same exact perspective" as you claim. I'd like to see how a lens can possibly create different perspectives (other than by standing someplace else - and I should rule out tilts and swings, not applicable here). Any lens merely captures what it sees there.

Photo perspective is caused simply by the geometry of where we stand (meaning subject distance). Of course, we can only see what we see when we stand there. All any lens can do in that same place is to take a picture of it, showing exactly what we see when we stand there. If we want any lens to see something different, we must stand at a different place. How hard is that?

Those differences in perspective simply can not be accomplished with another focal length while maintaining the same subject magnification.

Of course they can. Very easily. I just showed you in msg #6 of this thread.

The lens provides magnification of what we see, but really, the lens just frames the subject,

Where the camera stands determines perspective. What we see when we stand there is perspective.

If we want the same frame, yes, the lens is important too, frames are what lenses do.

If we want the same perspective, the place that the camera stands is the only thing that matters. (where we stand means subject distance, but of course we can make horizontal changes too)
By your "subject magnification", I ignore any the surrounding frame, and only look at the subject magnification.

I just showed you how in the photos in #6 of this thread. I just told you how to do it in my #25 here. Do you not read? I am expecting better of you Jsee. Your problem is that you seem only able to "measure" perspective by the outer frame (I call that angle of field of view, which is not a factor of perspective). I judge perspective by how the subject actually looks, relative say to the background. The spatial relationship of objects in the scene is perspective. The frame is only a border.

The various photos showing perspective differences supposedly attributed to the different lenses are falsely misleading, since they are only possible by standing at different distances to fill the existing frame. The distance is what affects the perspective. The lens merely provides the frame. A useful frame, but the lens does not affect perspective.

 

[Stoshowicz]

Look at these other examples all instructing on perspective ...

Picturecorrect.com Perspective in photography can be defined as the sense of depth or spatial relationships between objects in the photo, along with their dimensions with respect to the viewpoint (camera lens or the viewer).


Photinf.com
Let's have a look at a relatively wide focal lenght first: 28mm. The following image samples show 4 trees with an equal distance between neighbour trees. At the wide setting it seems that this distance actually increases dramatically towards the foreground (exponential behaviour of the distance). It other words: the tree to the left seems to be totally seperated from the rest of the gang. The background seems to be far in the distance.


Wikipedia
In photography and cinematography, perspective distortion is a warping or transformation of an object and its surrounding area that differs significantly from what the object would look like with a normal focal length,


Photographytuts.com
A wide angle lens will increase the perception of depth by singling out objects and therefore giving the impression of bringing them to the fore of the image. A telephoto lens that is zoomed in will do the opposite, and will compress the perspective, reducing the perception of depth by flattening out the objects within the image. So choose sensibly according to the type of work that you are undertaking.

Clearly this term and its mechanism is not being used consistently. But the general idea is that focal length is the aspect associated with perspective even though depth is at play. Like I said , I agree with the point Wayne is making, I just dont think the photographic community overall is taking the same vantage-point relative to the triumvirate nature of the phenomenon.

perhaps ..Almost everyone is wrong or misleading , in describing the way perspective works I think its commendable that you are willing to stand alone against the tide , in dissociating focal length from perspective.

 

[WayneF]

Clearly this term and its mechanism is not being used consistently. But the general idea is that focal length is the aspect associated with perspective even though depth is at play. Like I said , I agree with the point Wayne is making, I just dont think the photographic community overall is taking the same vantage-point relative to the triumvirate nature of the phenomenon.

perhaps ..Almost everyone is wrong or misleading , in describing the way perspective works

Yes, I agree, much inconsistency. Probably all are wrong or right in some degree, probably often errors of omission.
I think this Wikipedia text is poor, at least in this tiny context, I didn't see any more of it, but it is not how I would ever start.

Looking only at these brief quotes, the first two seem good, esp the first. But the last one photographytuts, is wrong in the sense this thread was wrong, they attribute perspective to the lens, when all that matters is where the lens stands. We can in fact create either effect they describe with either lens they mention, by merely choosing a different place to stand to do it. It's not the lens that directly does it. The lens merely takes a picture of the scene it sees when standing there.

Again, for portrait photos, it does not matter if using a long lens for head and shoulders, or a short lens for full length standing, it is extremely wise advice either way to be sure to stand back at least 6 or 7 feet for proper portrait perspective. Then use the lens that the framing needs.

 

[Stoshowicz]

Yes, I agree, much inconsistency. Probably all are wrong or right in some degree, probably often errors of omission.
I think this Wikipedia text is poor, at least in this tiny context, I didn't see any more of it, but it is not how I would ever start.

Looking only at these brief quotes, the first two seem good, esp the first. But the last one photographytuts, is wrong in the sense this thread was wrong, they attribute perspective to the lens, when all that matters is where the lens stands. We can in fact create either effect they describe with either lens they mention, by merely choosing a different place to stand to do it. It's not the lens that directly does it. The lens merely takes a picture of the scene it sees when standing there.

Again, for portrait photos, it does not matter if using a long lens for head and shoulders, or a short lens for full length standing, it is extremely wise advice either way to be sure to stand back at least 6 or 7 feet for proper portrait perspective. Then use the lens that the framing needs.

Yeah , I did take quotes to support my point , but figured it was fair because Im arguing for a broader definition rather than a narrower because I too think the presentations appear to be a cockeyed way to look at the issue. so , To me all of the quotes appear misleading actually.
If you wanted to find the extended versions most likely all you have to do is probably highlight the entire passage and google it as a whole search item. I didnt think it highly important since you arent actually confused about what you mean. I understand Jsee's argument as well,but the lines thing actually is kind of more mathematical than Im usually comfortable about. Like you said were starting to recover ground so Ill leave you to your own way of public clarification rather than insist on mine.

 

[J-see]

Not hypothetical at all...

Help lines for perspective are evidently heavily used in painting and drawing but it's not different for photography since they all have one thing in common: being a two-dimensional medium and thus suffering from "flatness". That's where perspective comes in to try and present an illusion of depth.


That's why I used the cube; it’s a very simple shape to show what perspective is about. That perspective is also present in the before shared images, at least in the ones with a shorter focal length. There you could draw the lines until they intersect and define the vanishing points and horizon. Those of course do not necessarily need to be "in" the shot.


So even if we get back to photography, the exact same perspective rules apply. We show depth by showing “imaginary” lines leading towards vanishing points. That’s the only way to create an illusion of depth in a two-dimensional medium.


The camera evidently only records what is in front of the lens but the lens affects what is shown in the photo and that does not need to correspond to what we actually see while taking the shot. I do not see the compression a 600mm lens shows nor do I see the “increased” distances extreme wide-angle lenses display so well. If I take a shot of my dogs with my 14mm; the shot shows an almost cartoon-like version. The camera does only record what we "see" while using a very limited focal length. All the rest is a distortion of the reality we perceive.


The lens defines the magnification of our subject which in turn defines the exact distance between the sensor and our subject when framing. If I want to take a portrait filling 2/3th of my sensor using a 135mm lens, I will have to stand at an exact distance from my subject to accomplish that. The compression of my lens will in turn define the perspective I can include within my shot. Even if there’s a building behind my subject, when using a long enough focal length I will not be able to include enough vanishing points because of compression while such is easy as pie when using a wide-angle lens.


Btw, I start to wonder if what you call perspective isn’t "angle of view" which depends upon where we point the lens yet, while it can affect the perspective of a shot, has little else to do with it.

To add some shots showing perspective in photography. Both wide angle, both different perspective.

 

[Stoshowicz]

Nah, the angle of view is part of what Im calling perspective , Wayne isnt including it and he isnt including 'croppage' either.

Picture this

Your sweetie's face covers the camera , so you back up, and then you start to see the mountains behind her , the farther you back up , the more her relative size fits the mountain. You change your focal length and it crops in on her and the image looks 'compressed'. (Because the lines of sight converge on a lens, and a focal length is just an angle of view, which is a crop essentially, ....,) Thats all there is to it All the examples one sees of telephoto effect or compression are just a combination of altered proximity to the subject and a crop, if you include it -- in the form of an altered focal length.

 

[J-see]

But that's not relevant to what was initially talked about: subject/background in portraiture.

The key here is that the subject remains identical in size which limits/defines the to-be-used distances and because of that, focal length/compression starts to play a serious role.

 

[WayneF]

The camera evidently only records what is in front of the lens but the lens affects what is shown in the photo and that does not need to correspond to what we actually see while taking the shot. I do not see the compression a 600mm lens shows nor do I see the “increased” distances extreme wide-angle lenses display so well. If I take a shot of my dogs with my 14mm; the shot shows an almost cartoon-like version. The camera does only record what we "see" while using a very limited focal length. All the rest is a distortion of the reality we perceive.

You're not paying attention to what you see then. There is only one possible perspective view from any given spot, and the camera cannot show something that is not there. The camera just takes the picture of the view already there. The lens can only magnify, but only where we stand can change the view seen. There's a cable TV show here on the National Geographic channel called Brain Games, and only a little is about perspective, but it delights in showing us how our brain fools us about what we think we perceive.

Take a baseball, put it on a table and shoot it with a 14mm at closest distance. Now you take a 600mm and reproduce that shot. You can stand wherever you desire to take the exact same shot with the exact same perspective distortion.

So I take it that you thought better about trying to show us any evidence of that notion? I don't blame you, I certainly would too, it cannot work that way. The lens does not affect perspective, but where we stand with it is all important.

I have already shown obvious evidence here of that correct thought (the lens magnification does not matter except to framing, only how far back we stand matters to perspective seen).

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The lens defines the magnification of our subject which in turn defines the exact distance between the sensor and our subject when framing. If I want to take a portrait filling 2/3th of my sensor using a 135mm lens, I will have to stand at an exact distance from my subject to accomplish that. The compression of my lens will in turn define the perspective I can include within my shot. Even if there’s a building behind my subject, when using a long enough focal length I will not be able to include enough vanishing points because of compression while such is easy as pie when using a wide-angle lens.


Btw, I start to wonder if what you call perspective isn’t "angle of view" which depends upon where we point the lens and, while it can affect the perspective of a shot, has little else to do with it.

LOL. That is hilariously weak. Sorry, no, it is you that imagines drawing a border around the image is perspective. I think perspective is the spatial relationships seen within the image, reproducing what can be seen from where we stand with the camera.

The lens is of course extremely linear, a lens has no compression. If it did, it would always be a problem, not just present when we thought we wanted it. Compression is of course instead caused by where we stand... the view seen from where we choose to stand, which view the lens will simply record.

Let's do drop it, this is just dumb, it isn't going anywhere. Neither of us are interested in the others notion.

 

[Stoshowicz]

Sure it is the compression effect is just as valid for your sweeties nose and the presentation of her portrait is altered by proximity- compression.
Holding subject size constant is the part that makes the issue appear confusing, because folks presenting the idea are changing two variables, focal length and distance, to get that effect.

 

[J-see]

you're not paying attention to what you see then. There is only one possible perspective view from any given spot, and the camera cannot show something that is not there.

This isn't there yet my camera is showing it. If you see this in reality, you need to go see a doctor.

 

[WayneF]

This isn't there yet my camera is showing it. If you see this in reality, you need to go see a doctor.

A. The idea is that the SLR viewfinder should show the picture it will take. If it doesn't, you should see a camera doctor. And without a camera, if you get your eye in that same place (up close), you should also see what the camera sees there, if you take notice.

B. The camera lens cannot make anything up. Some can magnify things, but see A.

 

[Woodyg3]

Wow, Wayne, I don't know how much more accurately and clearly you can explain perspective. For what it's worth, I agree completely that you are 100% correct.

J-see, your cube diagram proves Wayne's point. The perspective diagramed can clearly ONLY be seen from one viewing point. The diagram clearly shows this.

Aw, I was going to stay out of this. But this is Basic Art and Photography class stuff. I don't want any new photographers reading this and getting unnecessarily confused.

Look at the original post, see the differences in the portrait perspective due to focal length of lens, keeping the subject size the same, and CHANGING DISTANCE FROM SUBJECT. Understand that and you know what you need to as a photographer.

 

[J-see]

Since when do we suddenly change the previous use of "perspective" into "point of view"?

Isn't that what I said: your focal length defines how much perspective you see in your shot and in the end is responsible for differences in perspective?

It's focal length that affects it since focal length defines which distance we have to pick. Focal length in combination with a particular sensor.

If I have a 50mm on my FX and want a particular scene framed in a particular way, I can't randomly decide where I want to stand and make my 50mm fit.

If I put that 50mm on my crop, I again have to readjust my distance if I want the same scene.

My field/angle of view (degrees) limits me in how much I can frame of a particular something which forces the distance I pick.