The point is, the main factor is the distance of your point of view to the objects in the scene, it's not the lens that causes the compression. 'Lens compression' is a bad name.
May 7, 2023
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If the 15mm lens is f/1.4, then it's maximum entrance pupil is 15mm/1.4 = ~10.6mm. For the slowest 800mm lenses, say the Canon RF800/11, the maximum entrance pupil is 800/11 = ~71mm. From the same distance from a subject, relative DOF depends on the pupil size. So, even the slowest 800mm lenses have much, much shallower DOF than any 15mm lens cropped to an 800mm-FF-equivalent FOV.
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We'll just have to disagree on this one :-)
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That's only true if you don't crop and show the full image at the same size. As a person who takes a subject-oriented approach to photography, that seems like an artificial thing to do. What is your subject, the room, or the darts?
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I know what you mean, but these views don't look anything like actually being closer. They can just "feel" closer.
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The psychological compression effect has nothing to do with lens focal length, or with the lens, except inasmuch as DOF affects the visibility of the effect, but that is a function of pupil size and distance; not focal length. Using a narrow AOV at a wider angle of display is not a focal length phenomenon.
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Thank you for your thoughts. We clearly have a different definition of "lens compression" so we'll have to disagree on this one :-)
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Perhaps this thread could use more references and less unsupported statements.
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I don't have a definition of "lens compression", because there is no such thing as "lens compression".
All the phenomena spoken of here that are real, are due to relative magnifications of various objects in a scene due to relative distances, and that somewhat variable psychological effect of having significant angular magnification. A crop is as good as a long focal length, or even pressing your face up against a mural made from a wide angle lens.
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This is where we disagree. In the example I posted earlier, I mentioned that although nothing actually moved Object B will appear to be closer to Object A after you zoom in.
Many people call that "lens compression". If you don't want to call it that or prefer to call it something else that is fine as it is your choice to make.
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Some good animations and diagrams here:
mastinlabs.com/blogs/photoism/the-truth-about-lens-compression
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So you think that this shot is an example of telephoto compression?
That is exactly the sort of nonsense I was referring to in the title of this thread.
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That article is another example of the nonsense I mentioned in the title to this thread.
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So there's a lot of nonsense here except Tom. Is that right Tom?
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To those who argue that telephoto compression is all down to distances:
Suppose the scene in front of you is a long straight road with one vehicle 100 yards away, another vehicle 300 yards away, another 400 yards away and a fourth a mile away. If you take a shot from your present position, will it show telephoto compression?
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From the Wikipedia article:
"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"
If the angle of view of the image (as captured) is wider than the angle of view at which the image is viewed, wide-angle perspective distortion is seen.
If the angle of view of the image (as captured) is narrower than the angle of view at which the image is viewed, telephoto perspective distortion (more commonly called telephoto compression or lens compression) is seen.
Note that the angle of view at which the image is viewed depends on the viewing distance (relative to the size of the image).
(Unfortunately, that Wikipedia article, like many, also contains some incorrect and nonsensical statements.)
Another source of information about perspective is very old textbooks. Here are a few excerpts from " The Manual of Photography" (7th Edition, 1978):
The Manual of Photography, from which these excerpts are quoted, was first published in 1890 as The Ilford Manual of Photography. Early photographers had a very good understanding of perspective. It is sad that perspective is so poorly explained by many modern tutorials on photography.
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No, obviously not 'tele'. You missed the next image and its description, and quoted a part of my message out of context.
In the OP you claimed that the compression had nothing to do with the physical distances from the camera to the objects:
That's wrong on at least two levels: first, the compression is indeed due to distance; second, 'lens compression' is a misnomer, but as long as you use it, why do you call your perception of perspective when viewing a photo a 'lens compression'?
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I was asking about this image, not the next one. So, you agree that it does not show telephoto compression. Are you implying that it shows another sort of compression? If so, please explain what determines if a shot shows your sort of compression.
My position is very simple. A shot shows telephoto compression if it was taken with a longer than normal focal length and is viewed in the normal way. The degree of compression is equal to the focal length divided by the normal focal length.
Of course, the shot must be of a suitable scene for it to show any depth at all. If there is no apparent depth in the scene, it cannot show telephoto compression.
Definitions:
Normal focal length is equal to the length of the sensor diagonal (43mm for full frame).
Normal viewing is viewing from a distance equal to the length of the (uncropped) image diagonal.
Please state precisely how you would define your sort of compression.
