Ultra Wide-Angle distortion\compression question

[george013]

The bottom line, as my first boss told me way back in 1967 (I was then a very junior medical photographer) is that perspective is entirely and only determined by viewpoint.

The fact that zoomed in images look more compressed is caused by the fact that you have effectively cropped out the parts of the image that are nearer you and so lost the parts that are much nearer to you. You can enlarge a wide angle / short lens image to the same scale as a telephoto / long lens image and the images will be identical assuming the camera hasn't moved between the exposures. Sensor size is equally irrelevant. Viewpoint is all!

Martin

I must correct that.
Perspective is any suggestion of a third dimension in a 2-dimensional plane.. In the renaissance painters started to add perspective in their paintings. On way was to make use of lines. That's called the line perspective and that's what you're referring to.
Stating that "perspective is entirely and only determined by viewpoint" does me wondering what you mean with that. If my viewpoint is determined than the perspective is determined? Independent of the angle of view?. That would mean less thinking when making pictures.
The first part of the Vertigo movie shows a nice example of perspective manipulation. That guy is just standing on the stairs and making silly movements with his arms and face. Playing with a constant magnification of the person but changing the focal length and distance give you the suggestion he falls.
The change in magnification is the magic idea in this thread. And not compared to sensor size but to image size, so also including crops.

Just a Gooogle search on "different ways to add pespective", I just picked out 2.
http://vanseodesign.com/web-design/p...al-depth-cues/
http://www.digitalcameraworld.com/20...-perspectives/

George

[Dave Humphries]

George,

I think you may have missed the point of the OP's original post in challenging Martin's post.

While semantically your definition of the word "perspective" is correct, I'm not sure it is helpful to take this thread in that direction.

I acknowledge the links you provide are valid when considering the artistic concept of "perspective", but that's not what this thread is about.

Regards, Dave

[george013]

George,

I think you may have missed the point of the OP's original post in challenging Martin's post.

While semantically your definition of the word "perspective" is correct, I'm not sure it is helpful to take this thread in that direction.

I acknowledge the links you provide are valid when considering the artistic concept of "perspective", but that's not what this thread is about.

Regards, Dave

I already wrote over and out but I started again.

I didn't miss the point of OP. It's all about perspective. And see perspective as a change of magnification in a 2 dimensional plane of the 3th dimension. That's exactly what the line perspective is. The so called distortion of a wide angle lens is caused by an extreme difference in magnification.

Somebody else may take it over.

George

[xpatUSA]

I agree with George (no fainting, please).

Like many things photographical, "perspective" seems to mean different things to different people.

I like the "base" Wiki, which has a general definition of the word "perspectivity" (ugh):

https://en.wikipedia.org/wiki/Perspective

However, there seem to be at least five points-of-view on the subject.

This one seems to apply best here.

https://en.wikipedia.org/wiki/Perspe...photography%29

I like it that the Wiki actually qualifies the word - as in perspective distortion and further defines two forms of distortion: extension and compression:

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, due to the relative scale of nearby and distant features. Perspective distortion is determined by the relative distances at which the image is captured and viewed, and is due to the angle of view of the image (as captured) being either wider or narrower than the angle of view at which the image is viewed, hence the apparent relative distances differing from what is expected. Related to this concept is axial magnification -- the perceived depth of objects at a given magnification.
Perspective distortion takes two forms: extension distortion and compression distortion, also called wide-angle distortion and long-lens or telephoto distortion,^[1] when talking about images with the same field size.

I believe that the Wiki is credible and applies to the OP pretty well. Indeed, so well that I do prefer it to the many ad hoc definitions or explanations found in forum posts

[Dave Humphries]

Yes that last quote (via Ted) from Wikipedia gets my vote too.

... and George; yes, I appreciate your earlier contributions to the thread, which were indeed relevant to the OP.

[xpatUSA]

Saw this over on a Sigma forum elsewhere:




Just offered as an example of artistic usage of perspective distortion. Camera (not mine) is a Sigma dp0 Quattro 14mm (21mm equivalent, not real 'ultra'). More here:

http://www.dpreview.com/forums/post/56474342
.

[William W]

. . . Like many things photographical, "perspective" seems to mean different things to different people. . .

It shouldn't.

I think it is very important to take the time to qualify both of the word 'perspective' and also the word 'distortion' to ensure precise meaning: the words do indeed have different meanings, depending upon the context in which they are used.

***

Perspective (of the image) is dependent upon: the DISTANCE from CAMERA to SUBJECT and the CAMERA ELEVATION relative to the SUBJECT.

On the other hand and for just one example: Distortion (of a lens) might be BARREL Distortion or PINCUSHION Distortion.

***

Unfortunately, (in my opinion), the Wikipedia definition of "perspective distortion" (as quoted by Ted - I haven't read through the whole document), is most insufficient.

Whilst the wiki definition takes into account the CAMERA to SUBJECT distance aspect of PERSPECTIVE when it discusses 'perspective distortion', it seems to ignore the aspect of CAMERA ELEVATION relative to the Subject.

As a result the wiki explanation limits 'perspective distortion' to 'extension' and 'compression' but does not include those 'perspective distortions' caused by moving the camera to a low or high CAMERA ELEVATION relative to the SUBJECT and then tilting the camera to Frame the Subject. CAMERA ELEVATION is the often forgotten element of 'PERSPECTIVE' .

The resultant 'perspective distortions' caused by an unusually high or low Camera Elevation are more commonly referred to as 'Keystone Distortion' and 'Convergence'.

***

Also, it is important to note that many 'distortions' (both LENS distortions and PERSPECTIVE distortions) may present simultaneously in the one image:



WW
Images © AJ Group Pty Ltd Aust 1996~2015, WMW 1965~1996

[tao2]

Ach well, in for a penny - in for a groat...

Technical - The lens...

A wide angle lens has a focal length shorter than the diagonal of the image format. A simple explanation but tending tae tie-in focal length tae angle of view. This is, of course not fundamental, as there's no direct relationship. It's simply that, out of any number of lenses for a particular camera, the shorter focal lengths have the greater angle of view.
The reason for that is related tae focal length in that it controls image size. So the shorter the focal length, the smaller in scale parts of the object(s) are produced and the more of the object ye get on the film/sensor.

Physical...

A wide angle lens has tae provide a sharp image from rays emerging from the back of the lens at acute angles. These rays travel much farther than the axial (central) rays and so the aperture is "seen" as an ellipse and not a circle. On small format cameras, these rays are used much less than on larger formats, thus the designer has much less tae worry about. The wider the angle, the more difficult this becomes. Advantages of wide angles is that they cannot be duplicated (except by a wider angle). A long focus lens can be imitated by a shorter lens by enlarging a part of the image. A wide angle takes in a much greater area of a scene and ye can't replicate that with a longer lens - except by changing yer viewpoint . Which means ye change perspective and so ye have a different photo...

A simple and clear explanation of perspective which ah read somewhere is - " the apparent size relationship between objects at different distances from the observer. Distant objects that look smaller than nearby objects which are, in reality, the same size. The closer you are to a nearby object, the greater the apparent disparity in size. Conversly, the farther away the objects are, the greater the separation has to be, before any difference in size between them becomes apparent."

The phenomenon described above leads tae the mistaken idea that wide angle lenses produce perspective distortion. This apparent distortion is caused by the close viewpoint afforded by wide angle lenses. It is actually correct perspective as yer eye would see it from the same viewpoint. Viewing the image from the theoretically correct distance, it will look natural. Most small discrepancies would be eliminated by the eye as the brain tends tae discard "wrong" perspective.

A contact print from film/sensor should be viewed from the focal length of the lens. Viewing an enlargement of, say a 24mm lens at 5x, it should be viewed at around 120mm (about 4.5 inches). Such enlargements are usually viewed around 250mm (10") so perspective looks all wrong.

Wide angle lenses do cause distortion. Solid objects at the image edges look wider than same sized objects in , or near, the centre. A 3D object like a sphere shows a strongly angled aspect in respect of the film plane. A sphere on the lens axis has equal light paths but... projecting from the back of the lens, the light path from the outer edge is greatly increased and thus image magnification increases towards that edge. That image becomes misshapen, a column appears wider but a sphere or sphere-like object becomes pear shaped.

The above is true wide angle distortion, having nothing tae do with viewpoint and only affecting 3D objects.

[george013]

William,

Perspective (of the image) is dependent upon: the DISTANCE from CAMERA to SUBJECT and the CAMERA ELEVATION relative to the SUBJECT.

This is the same. The subject has dimensions. Elevating the camera means you're using different distances to the same object. Thus using different magnifications in that same object. The shorter your distance to the object, the bigger the diffferences in magnification due to elevation.

Whilst the wiki definition takes into account the CAMERA to SUBJECT distance aspect of PERSPECTIVE when it discusses 'perspective distortion', it seems to ignore the aspect of CAMERA ELEVATION relative to the Subject.

It's AND the angel of view. And again camera elevation is using different distances to different parts of the same object. As used in your photo.

From the tutorial on this site https://www.cambridgeincolour.com/tu...gle-lenses.htm
You see the difference in magnification with the wide angle is bigger, using the same framing of the main object.



George

[William W]

(William wrote) - Perspective (of the image) is dependent upon: the DISTANCE from CAMERA to SUBJECT and the CAMERA ELEVATION relative to the SUBJECT.

(George replied) This is the same. The subject has dimensions. Elevating the camera means you're using different distances to the same object. Thus using different magnifications in that same object. The shorter your distance to the object, the bigger the diffferences in magnification due to elevation.

No, it is not the same. Elevating the camera to does NOT necessarily mean that the Camera to Subject Distance changes by any appreciable / significant distance.

In the sample image that I provided above, the principle Subject Element is the Head (Face). The Camera to Subject Distance can remain the same (and it did remain the same) as I moved the Camera lower to create the example of CONVERGENCE (as evidenced in the Shape of the Head).

***

Another good example is the PERSPECTIVE (of an image) of a Batsman at a CRICKET MATCH:

Image one: is taken just beyond the Boundary Fence, behind the Bowler’s Stumps where the camera is situated about 6ft above the ground. This is a typical ground-level Television shot.

Image two: is taken at the same distance behind the Boundary Fence, but from a tower elevated about 40~50ft above the ground. This is also a typical Television Shot.

The PERSPECTIVE of the Batsman and the Cricket Wicket in those two images are totally different, yet the Camera to Subject distance is the same and only the Camera Elevation changes.

WW

[William W]

Just re reading the entire thread and using the term “perspective” as it applies to simple PHOTOGRAPHY:

Post 20: The bottom line, as my first boss told me way back in 1967 (I was then a very junior medical photographer) is that perspective is entirely and only determined by viewpoint . . . Viewpoint is all!

That’s it in a nutshell.

And ‘Viewpoint’ comprises: SUBJECT DISTANCE and CAMERA ELEVATION.

When the DoP instructs the Cinematographer of ‘the shot’, the first instruction is the Camera Viewpoint this has two components, being (a) Camera to Subject Distance and (b) Camera Elevation. The Camera Viewpoint then determines the Perspective of The Shot. The second instruction is the Focal Length of the Lens and this instruction determines the Field of View of The Shot.

Some of the other commentary in this thread uses the word ‘perspective’ to speak of and refer to ART (i.e. Painting and Drawing) and the word ‘Perspective’ in that application is related to, but not the same as using the word ‘perspective’ as a Technical Term in Photography. For one example, Artists are quite free to make their perspective FALSE: and much Art (Painting, Drawing and Sculpting) does indeed contain false perspective.

Mechanical Drawing (or Drafting) has various TYPES of ‘perspective’. For example there is a simple one point ‘perspective’ style of drawing and then, a more complex two point ‘perspective’ style and these might have other layers of complexity, such as the type of ‘projection’ that is used, for example isometric or oblique projection.

Then also, in PHOTOGRAPHY we have the more colloquial and NON-Technical Term ‘perspective’. This usage is especially common when it is used as an adjective (or compound noun) such as “Perspective Distortion”. This colloquial compound noun “Perspective Distortion” seeks to group all the Technical Terms, for example ‘Foreshortening’; ‘Compressing’; ‘Extending’; Keystoning’; ‘Converging’ – and sometimes also confuses some of the DISTORTIONS of a LENS and incorrectly groups these distortions under the colloquial umbrella of ‘Perspective Distortion’- a common example of this confusion is when BARREL DISTORTION (of a wide angle lens) is mistaken for COMPRESSION or FORESHORTENING caused by the combination of short SUBJECT DISTANCE and WIDE ANGLE LENS.

BTW the term 'Perspective Distortion' as described in the para. above, is not new terminology. The term is referenced in many (older) Technical Photography Texts and is well documented as having that meaning, pertaining to 'simple photography' throughout the later part of 20th Century when the smaller Viewfinder; Rangefinder; TLR; and SLR cameras became very popular and began to replace the larger and more cumbersome Technical Cameras. For one example: The Ilford Manual of Photography, Fifth Ed. 1958 - pp 87, 93 ("with wide angle lenses"); p93 ("with long focus lenses"); pp92, 94, 95 ("by viewing prints at incorrect distances").

Note that the opening sentence of this commentary mentions “using the term ‘perspective’ as it applies to simple PHOTOGRAPHY” (my bold now for emphasis). ‘Perspective’, as it applies to PHOTOGRAPHY, can indeed become more complex when it applies not to ‘simple’ Photography, by that I mean when the Photographer is using a CAMERA with MOVEMENTS for example a FIELD CAMERA or a VIEW CAMERA. A reasonable facsimile of using a Camera with Movements is attained when using a DSLR (or SLR) with a lens that has both TILT and SHIFT facilities. In these cases, whilst there are still rules for ‘perspective’ the simplicity of that ‘perspective’ becomes more complex and, for example, might allow the photographer to overcome some of the ‘perspective distortion of the image’ – a common example of which is overcoming the CONVERGENCE of the Vertical Lines of a (tall) Building when the Camera ELEVATION is near Ground Level. An example of this can be viewed at this CiC Link.

I think that it was reasonably obvious the Opening Post was describing and asking about ‘perspective distortion’ of the image. (These are not distortions of the lens).

Further, I think that it was reasonably obvious the Opening Post was describing ‘perspective distortion’ as it applies to the Subject of Simple Photography. (Simple Photography is not Art; Painting; Sculpture; Technical Drawing; or when using the more elaborate TECHNICAL CAMERAS, such as Field Cameras and View Cameras or Lenses with Tilt and Shift Movements).

If that was not obvious in the Opening Post, then is was certainly obvious that the initial responses were addressing this subject of ‘perspective distortion of the image’ and as that relates to ‘simple photography’ and this is summarized by Manfred’s opening sentence in post #12, viz:

The distortion you are concerned about has nothing to do with the lens focal length, but is associated with the camera to subject distance.

The whole point of Dave Humphries' post #22, was to ensure (perhaps hopefully ensure) that the conversation stays on the topic of ‘perspective distortion of the image as it applies to simple photography’ and that the clarity of meaning and quality of discussion is maintained by not diluting the conversation with other definitions of ‘perspective’ which are more applicable to Art and disciplines, other than Photography.

WW

[george013]

William,

This thread is about "distortion" of wide angle lenses. The perspective used in this context is solely the line perspective. That line perspective causes a difference in magnification . Ones that differences in magnification exceeds a certain point, we experience that as unnatural, distorted.

No, it is not the same. Elevating the camera to does NOT necessarily mean that the Camera to Subject Distance changes by any appreciable / significant distance.

In the sample image that I provided above, the principle Subject Element is the Head (Face). The Camera to Subject Distance can remain the same (and it did remain the same) as I moved the Camera lower to create the example of CONVERGENCE (as evidenced in the Shape of the Head).

Don't think in distances as a distance to the point you focused on but to the plane parallel to your sensor you focused on. Elevating your camera has influense on that. It's shouldn't be to difficult to draw it and to "catch" it in a mathemathical formule.

Another good example is the PERSPECTIVE (of an image) of a Batsman at a CRICKET MATCH:

Image one: is taken just beyond the Boundary Fence, behind the Bowler’s Stumps where the camera is situated about 6ft above the ground. This is a typical ground-level Television shot.

Image two: is taken at the same distance behind the Boundary Fence, but from a tower elevated about 40~50ft above the ground. This is also a typical Television Shot.

The PERSPECTIVE of the Batsman and the Cricket Wicket in those two images are totally different, yet the Camera to Subject distance is the same and only the Camera Elevation changes.

That's composition you're talking about now. As I stated before, to me pespective is any suggestion of a third dimension in a 2 dimensional plane. It became part of this discussion for people also say that perspective is related to the viewpoint/plaace of the photographer.

When talking in the context of wide angle lenses, the we are talking about line perspective. And when talking of that specific subject, we must first define it. I did and it's a different magnifictaion of subjects in real distance seen on a 2 dimensional plane.

I don't know about cricket.

George

[William W]

William wrote: Another good example is the PERSPECTIVE (of an image) of a Batsman at a CRICKET MATCH:

Image one: is taken just beyond the Boundary Fence, behind the Bowler’s Stumps where the camera is situated about 6ft above the ground. This is a typical ground-level Television shot.

Image two: is taken at the same distance behind the Boundary Fence, but from a tower elevated about 40~50ft above the ground. This is also a typical Television Shot.

The PERSPECTIVE of the Batsman and the Cricket Wicket in those two images are totally different, yet the Camera to Subject distance is the same and only the Camera Elevation changes.

That's composition you're talking about now.

No. It is NOT an example of "Composition"

It is an example of a change in PERSPECTIVE of the Image or 'The Shot'. It is a classic and also text book example of that. It is one of the simplistic examples of Change of Perspective of The Shot which is taught in First Year Cinematography and Television. (T.V.O.C.P.)

***

. . . As I stated before, to me pespective (sic) is any suggestion of a third dimension in a 2 dimensional plane. . .

Yes.

That is understood by me and I expect it is understood by others also.

It appears to be the sole predicate upon which much of your commentary on this thread is based and the reason why those parts your commentary based upon that restrictive definition appears out of kilter with many of the other comments.

Accordingly and because we each choose to define the topic of conversation differently it serves no purpose to continue and I shall withdraw from further discussion with you on this topic.

All the best to you.

WW

[george013]

I stopped twice allready.

If you change the viewpoint you change your composition.

It is an example of a change in PERSPECTIVE of the Image or 'The Shot'. It is a classic and also text book example of that. It is one of the simplistic examples of Change of Perspective of The Shot which is taught in First Year Cinematography and Television. (T.V.O.C.P.)

I don't know how you can change the perspective in an image. An image is statical. I don't know about your examples of Change of Perspective of The Shot, but I think you refer to what in the Vertigo video is shown. That's no photography. But it shows what I try to say all the time: a difference in magnification of 2 subjects in the depth. Wide angel is big difference is big depth feeling, small angel is small difference is flattening.

I'll stop again. Lot of reading but no reaction.

George

[pnodrog]

Perspective is as previously stated solely dependent on viewpoint.
Distortion is due to deficiencies or limitations in lens design.

What seems to be overlooked in this discussion is our perception of what looks normal is due to human vision having a viewing angle of about 54 deg with peripheral vision extending to about 70 deg. The images taken with perfectly corrected ultra wide angle or long telephoto lenses are neither "distorted" nor "compressed" but simple display relationships that are beyond the capacity of our unaided vision system. To us they look unnatural because from a given viewpoint/perspective our eyes cannot capture the relationships that some lenses can.

I wonder what a fish, frog or fly would make of this discussion.......

[george013]

Perspective is as previously stated solely dependent on viewpoint.
Distortion is due to deficiencies or limitations in lens design.

Well, then you can go in discussion with William. Both he and me have other ideas of perspective.

George

[pnodrog]

Well, then you can go in discussion with William. Both he and me have other ideas of perspective.

George

Do not need to discuss it thanks......

[george013]

William,
One more about the camera elevation.
Below a normal setup.
The focus plain(?) is a plain perpendicular on the optic ax.
The magnification is focal length/subject distance, not counting macro.



Then we elevate the camera. The focal distance stays the same. The top and the bottom of the subject are going through different focus plaines(?). Those plaines have different distances to the optical centre, so different magnifications. In this case the bottom of the subject will be more magnified as the top. Thats also the story behind the Keystone effect off which I never heard before.


Going back to the thread. As I wrote before, the magic word is magnification, and more directly the difference in magnificartion.

Over and out out ot out.

George

[William W]

For the archival integrity of this conversation and for clarity of meaning of the technical words which were previously used, here are some individual but related points for consideration for those who are interested in this topic:

***

Please refer to this diagram:

1. The above, the second diagram in Post #38 does NOT illustrate a CHANGE in CAMERA ELEVATION,as that term 'camera elevation' has been used in this conversation regarding 'Camera Viewpoint' and 'Perspective'

The diagram illustrates CAMERA TILT of a simple camera. That is to say the Camera is tilted so that the Film Plane (or Sensor Plane) is not parallel to the ‘face of’ the Subject. Usually and for most simple photography, this means that the lens’s axis is NOT parallel to the ground.

(N.B. This is ‘Camera Tilt’ of a Simple Camera, as opposed to ‘Lens Tilt’ or ‘Back-board Tilt’ of a Technical Camera).

Assuming the liberty of using George's illustration (please) and overlaying on it, the below yellow and red, represents a change in CAMERA ELEVATION:



***

2. Concerning ‘Keystoning’ and ‘Converging’:


‘Keystoning’ or 'Keystone Distortion' and ‘Converging’ or ‘Convergence Distortion' are a result of the Film Plane (or Sensor Plane) NOT being parallel to the (vertical or horizontal) Plane of the Subject.

Two simple examples are standing near a tall building and looking up, vs. standing far away from a tall building and looking at 90° to the front face of it.

When we are close to the building and look up the vertical lines of the side of the building appear to converge, this is ‘Convergence’:



However, if we can get far enough away from a building and manage to keep our Film Plane parallel to the face of the building we will make an image which is geometrically correct in respect of the vertical and horizontal edges (that is if the Lens does not have Distortion, for example the lens needs to be free from Barrel or Pincushion Distortion):



***

3. Special note about the term 'Keystoning'

‘Keystoning’ the opposite of ‘Converging’, although ‘Converging’ is often used to mean also ‘Keystoning’: that is to say ‘Keystoning’ is when the vertical edges of the Subject converge downwards in the image, rather than upwards in the image:



The term ‘Keystoning’ and ‘Keystone Distortion’ is derived from the shape of the Mason’s ‘Keystone‘, which is used to lock an Arch.

***

4. CAMERA ELEVATION and CAMERA TILT and PERSPECTIVE

After re-reading the thread and especially considering Post #38, it occurs to me that there probably existed a misunderstanding of the term “Camera Elevation” and specifically this term might have been misinterpreted or misunderstood by George. I trust this clarifies what exactly Camera Elevation is and what Change in Camera Elevation means.

Obviously applying a Camera Tilt without making any change in the camera's ELEVATION might cause convergence in many Subjects within the scene.

More importantly, the Camera Tilt will introduce new elements into the scene - BUT - even with Wide Angle Lenses used at close distances there will be very little, if even any perceivable change in the Perspective of the elements which are in both scenes.

If you’ve read this far, and are still interested in this topic, then please refer Posts #30; 32; 33; 34 and this statement and the conversations concerning it:

William wrote: Another good example is the PERSPECTIVE (of an image) of a Batsman at a CRICKET MATCH: . . . etc

The example involved a large playing field and a long Subject Distance and I have plenty of images illustrating how a change in Perspective will be caused by Changing the Camera Elevation.

But subsequently, it was mentioned that this thread particularly concerns Ultra Wide Angle Lenses when used at Short Subject Distances. Also it seems possible that the image sample provided in Post #27 did not adequately illustrate how a Change in Camera Elevation does change the Perspective of The Shot even when using a UWA Lens at a Short Subject Distance.

Therefore below is a set of four images made to illustrate this point. All the images are JPEG SOOC made with an 5D Series Camera and a lens set at FL = 16mm. The typical SD is about 24 inches, thus this A:B:C:D comparison meets the criteria of “UWA Lens used at a Short Subject Distance”:



The main Subjects are: Jewellery Box; Fish; Stuffed Bear. Please concentrate on those as being the Subjects of the Scene.

Image A is the Camera’s Sensor Plane parallel to the ‘face of’ the Main Subjects – i.e. NO TILT

Image B is the Camera TILTED downward.

Image C is the Camera TILTED upward.

Image D is the Camera’s ELEVATION moved upward and NO TILTING of the camera.

Ignore the BARREL DISTORTION created in the Subjects (especially the Fish in Image B).

When the camera is TILTED in images B and C, whilst ‘convergence’ in definitely noticeable in Jewellery Box and Fish: the PERSPECTIVE (the internal relationship of the three main Subjects) remains the essentially the same in the three shots A, B and C.

However, the PERSPECTIVE of The Shot does change noticeably simply by Changing the Camera ELEVATION in Image D

*

After the Camera Elevation is changed, and upon RE-FRAMING the SUBJECT, there often is (probably nearly always is), a necessity for CAMERA TILT to be applied to make the COMPOSITION more acceptable:



Certainly this Camera Tilt (because of the Change in Camera Elevation) may cause ‘converging’ or ‘keystoning’ in individual the Subjects within in the Image: but it still remains that the change in Camera Elevation causes the change in the Perspective of The Shot.

*

5. Do it yourself, without a camera

One doesn’t need a camera to see how CAMERA ELEVATION will change the PERSPECTIVE of The Shot and the relationship between the Subjects within that scene: simply go to any Field Sporting Event and look at the players on the field from Ground Level and then go high into the Grandstand and compare and contrast what you see – the two images have an entirely different Perspective.

WW

(except illustration in Section 1)
All Images ©AJ Group Pty Ltd Aust 1996~2015, WMW 1965~1996

[george013]

William,
You see, good guys never stop.

I tried to check what you could meant with elevation. At last I thought you meant elevating only the lens. That's where a drawing can be clarifying. Excuse for the misunderstanding, but the theory was correct.

When elevating you don't change your focus plaine(?).

Perspective is a difficult idea. It's a suggestion of that third dimension. Line perspective is rather easy to describe. In your photo D, only elevation, the top of the desk is coming visible and with that forward going lines adding more perspective to the image.


Is there a reason for shooting photo's after elevation. It seems to me that one can do the final composition at once and focus on the subject out of the center. Or is this technique meant when you're not able to focus on the border?

I know the keystone in arches. Sometime nice decorated. But I can't see a correlation with photography.

One doesn’t need a camera to see how CAMERA ELEVATION will change the PERSPECTIVE of The Shot and the relationship between the Subjects within that scene: simply go to any Field Sporting Event and look at the players on the field from Ground Level and then go high into the Grandstand and compare and contrast what you see – the two images have an entirely different Perspective.

This is a good example of the different perspectives. Perspective as an overall suggestion of that third dimension is enlarged by the low position. But the line prespective is the same. It also depends how one approaches this.

Thanks for the answers.

George