Talk:Field of view

Field of View vs. Visual Field

The article currently implies that the field of view and the visual field are the same thing. I believe that they are actually so different that they would deserve separate articles. To me, the field of view is more related to a specific situation, like "my field of view was blocked by a truck (and therefore I could not see the bicycle crossing the street)", while the visual field is an abstract concept in the sense of a 2D-image representation of the real world by the visual system. --Dontaskme 19:05, 22 August 2005 (UTC)

Uh. I fail to see the distinction you are making. Graft 19:38, 22 August 2005 (UTC)

OK, I'll try to make a better effort in explaining what I mean. The article states (correctly, as I believe), that "the field of view is the part of the observable world that is seen at any given moment." That means, it relates to a specific situation in which the person (or animal or machine) is interacting with it's environment. In a more limited definition, the field of view might only be considered that part that is currently relevant for the person's task or action, and irrelevant objects that are blocking the view are shrinking the field of view even though these objects are of course visible (cf. my example above with the truck). The visual field, on the other side, is a mapping of retinal locations to the real world, that is unrelated to any specific situation. It's more a philosophical-physiological concept. Maybe, one could say that the visual field is the 'sum' of all receptive fields. But since the definition of "receptive field" usually uses the term "visual field", this is not very helpful. Another example: If you look into a rear-view mirror and observe the traffic behind you, your field of view is partly behind you. The visual field, however, is unaffected by the mirror, in the sense that it is a 2D mapping between the outer world and the retina. Only, there happens to be a mirror in the visual field that shows things that are behind you. I'm afraid that this new explanation does not really help much more. The article cited here might help us, but I don't have it right now. If I find time, I'll get it.--Dontaskme 20:19, 22 August 2005 (UTC)

I have now read the above-mentioned article. According to the author, the term 'field of view' refers to "the physical objects and light sources in the external world that impinge on the retina." The visual field "forms the input to the computational mechanisms of the brain [...]". In contrast, the term 'visual field' refers to "the spatial array of visual sensations available to abservation in introspectionist psychological experiments". The visual field "forms the output of the representational mechanisms of the brain". While this is not exactly what I said originally, I would more or less agree with this definition, though the use of the term "visual field" in neurology and ophthalmology seems to be slightly broader that the one cited. Dontaskme 23:35, 19 September 2005 (UTC)

Something more to add: Today, I asked a colleague of mine whose main area of work are visual field defects. She also believes that that the visual field and the field of view are two different things. If there are no objections, I will try to split the current article into two that hopefully accurately describe the two things. Dontaskme 22:24, 20 September 2005 (UTC)

I have now created an extra visual field article. Eventually, some of the information from the field of view article should be moved over there. Dontaskme

I disagree with this distinction - if you mean to say, "field of view" implies everything I can see, whereas "visual field" means the portion of physical space that maps to my retina, I think the two are identical. In your above example, you assert that the rear-view-mirror increases your "field of view". Not so - that's only because your brain further interprets the image of the mirror to mean that which is behind you. In point of fact you can only ever see a specific subset of radians. Graft 14:51, 3 October 2005 (UTC)

I agree with Dontaskme. The information and images regarding visual field loss are better suited in Visual field, so I have moved them. There is probably quite a bit of information that should be there instead of here. AED 22:22, 2 October 2005 (UTC)

I agree with Dontaskme in that there is a confusion of concepts here. As a vision scientist working on the human visual field I am confident to say that the term “field of view“ is rarely if ever used in scientific writing on human vision to describe “the extent of the observable world that is seen at any given moment”. The proper term there to describe that extent is the “visual field”. If the term “field of view” is used in the context of human vision it is, as Dontaskme said, to describe a restriction imposed by apparatus (e.g. in “Restricting the field of view: Perceptual and performance effects. PL Alfano, GF Michel - Perceptual and motor skills, 1990”).

If judged by the stated definition, the two concepts seem to agree, as Graft said. However, for human vision the above definition is vague because it is not clear what “seen at any given moment” means: That seems to exclude eye movements (as required for the definition of the visual field), but what is seen at any moment, i.e. the percept, is some integration across saccades.

(With respect to the term FOV in human vision, there is further the concept of a “useful field of view” (UFOV) which is something different altogether.)

For animals, the use of terms seems to vary across species. For monkeys, which are similar to humans, the term "visual field" dominates in Google Scholar. For spiders, FOV dominates a little.

So to be consistent with current terminology, the term FOV in the section “Humans and Animals” should (at least for humans) be replaced by “visual field”. Otherwise the section could stay mostly unchanged or could be moved to “Visual Field”. (The entry “Visual Field” currently has problems of its own.) Strasburger (talk) 23:00, 6 May 2015 (UTC)

Future expansion topics

Would be useful to have a general discussion of the FOV of various movie cameras, video games, and 360-degree Circlevision cameras. Tempshill 18:04, 2 November 2005 (UTC)

Field of view vs. Angle of view

How does Field of view relate to angle of view? This article currently states that humans have a 180 degree field of view, but angle of view says that a fisheye lens has an angle of view of 180 degrees, and human eyes don't have fisheye lenses. Hackwrench 04:46, 13 September 2006 (UTC)

The two are really the same, just that one or the other is more popular in certain contexts. Angle of view is always measured in angular units (degrees, radians, and so on), but "field of view" is often used if non-angular units are used (such as "200 feet at 1000 yards" for the field of view of a pair of binoculars). Humans with normal vision have a 180-degree field of view/angle of view (at least, from left to right; might be smaller up to down--it is for me anyway), approximately, and so do fisheye lenses (which compress the field of view, such as onto a flat photograph).--Todd 17:49, 13 September 2006 (UTC)

But wouldn't that mean one should be able to see something flush with the eye, the eye looking forward, no matter how far away from the side of the face it moves? I'm trying to figure out how it relates to generating 3d computer models in the proper perspective. I think that a significant number of readers will be coming here with that in mind. Hackwrench 20:23, 14 September 2006 (UTC)

As is discussed in the article, acuity varies across the visual field - peripheral vision is much weaker for regular daytime vision since there's far fewer rods and cones than in the macula. So, to say that you can "see" something at 90 degrees to your left or right is strictly true, but you may not be able to see it very well. However, you're pretty good at detecting motion there. Not really sure what this has to do with 3d computer models... Graft 21:26, 14 September 2006 (UTC)

The article stated:

The field of view (also field of vision) is the angular extent of the observable world that is seen at any given moment.

and

Although related, FOV is not exactly the same as angle of view; FOV is measured in linear, spatial dimensions (feet, inches, metres, etc) whereas AOV (more properly called the angular field of view) is measured in degrees of arc.

I have amended the former to be more general. —DIV (138.194.12.32 (talk) 04:04, 13 November 2009 (UTC))

Birds with 360-degree field of vision?

The article states that some birds have a complete field of view of 360 degrees. The statement absolutely needs a source or examples of such birds. --Gwaur ^(Spokening) 16:34, 1 June 2007 (UTC)

I agree. The claim seems dubious, and I marked it as such. --Stybn 21:01, 2 June 2007 (UTC)

Claim is not dubious - Look up American woodcock. —Preceding unsigned comment added by 140.247.236.228 (talk) 22:01, 20 October 2007 (UTC)

Indeed, this claims that the American Woodcock has 360° vision, citing: Keppie, D. M., and R. M. Whiting, Jr. 1994. American woodcock (Scolopax minor). In A. Poole and F. Gill, editors. The birds of North America 100. Academy of Natural Sciences, Philadelphia, Pa. American Ornithologists' Union, Washington, D.C. 28 pp. I'm not hunting that down, but I'm removing "dubious" tag. --Stybn 08:06, 21 October 2007 (UTC)

Predatory animals often have both eyes facing forward, to maximize depth perception via parallax (eg lions). The price for overlapping the field of view of each eye is a smaller field of view overall. Conversely, many non-predatory animals (eg horses) have eyes which basically point more in opposite directions, giving them a huge field of view (so they can see the lions coming) but little parallax (so they're more likely to trip over the lion). Of course there are also many, many exceptions to this rule (eg octopi). Redbobblehat (talk) 00:18, 25 August 2008 (UTC)

Diagonal Field of View for Wide Angled Lenses

There is an apparent problem with the diagonal field of view for very wide angled lenses. When looking at a scene with a very wide angled lens, the vertical and horizontal fields of view are fairly well defined, but the diagonal ones are a problem. In a digital camera for example, I have noted that if a lens and sensor system is so designed that a 640x480 pixel array fits tidily into a lens image circle, then the light falls off towards the corners of the pixel array, as the corners of the pixel array tend towards the edge of the image circle. Thus, the corners of the image become darker and darker until they fade to black. So the question arises, how does one define the field of view here? Is it best to say that the diagonal field of view periphery is corresponds to the pixels that are receiving x% of the light falling on the centre.

I have seen several treatments of this online, but it seems to me that the only good way to do this is to agree an --x-- % relevant to the application and test the lens / sensor system pointing at a evenly lit white target.

Are there any thoughts on this out there? -- PD 19:55, 1 August 2007 (UTC)

The problem you have is vignetting, which is measured by relative illuminance across the image. Field of view is not an optical measurement of image quality, but a way of measuring spatial geometry; describing how a (theoretically perfect) camera relates to its environment. If the vignetting is mechanical, the field of view may be considered circular rather than rectangular, and the reason it appears blurred is because the offending aperture (whatever it is) is out of focus. Geometrically, however, the edge of the circle can be measured definitively. Redbobblehat (talk) 21:58, 24 August 2008 (UTC)

Dubious definition

All the photography books I can find define FOV as what we call angle of view, not the unsourced definition in this article. Does anything know why it says what it does, or where to get a source for it? Dicklyon (talk) 06:54, 17 December 2010 (UTC)

More Neutral Image

In case a illustration of equal quality, not featuring a military drone, could be found I would find this more tasteful. — Preceding unsigned comment added by 129.206.128.16 (talk) 07:36, 17 June 2015 (UTC)

Find one then. Seems perfectly OK to me at the moment. Grognard Extraordinaire Chess (talk) Ping when replying 00:18, 16 October 2015 (UTC)

I concur that the images of a military drone were incongruous and not particularly relevant to the article's likely readers. I have replaced them with images from elsewhere on the Wiki illustrating the FOV for humans. --Toddfast (talk) 18:20, 30 October 2020 (UTC)

It's a nice image, illustrating the FOV of the telescope, and fits well for the article. It is not related to the FOV of humans, however, so I have changed the legend slightly. Strasburger (talk) 07:50, 1 November 2020 (UTC)

Italian Content?

Why is not possibile to add italian language link to this page? (https://it.wiki.x.io/wiki/Campo_visivo) thank u — Preceding unsigned comment added by White wolf (talk • contribs) 02:05, 17 February 2016 (UTC)

Article is misleading or incorrect

I don't have the time or resources to dig into the cited articles, but the 210 degree figure is incorrect for what I believe this article is meant to explain. I believe this is a case of conflating the full range of vision when allowing eye movement with the range from unmoving eyes focused forward. There are many sources which put a the "forward facing" horizontal range at 120-130 degrees. Diagrams that include the 210 degree figure usually make this distinction clear. The vertical range is less of an issue, since the limiting factors (cheek and brow) are give approximately the same range as the eye in any case.

If the article IS about full "looking around" field of view, then there are several misleading statements in the text. LordQwert (talk) 18:50, 27 March 2021 (UTC)

You might be confusing the (size of the) field of view with the (size of the) visual field. The latter is about 210° horizontally or plus/minus 105° to the side. Per definition, this is without eye movements. The reason why this is more than the often-cited plus/minus 90° = 180° is explained in ref 6 (online). In brief, it is because light rays that enter from the side are refracted at the cornea. There are two figures in ref 6 (Fig. 8 and 7) which explain this.

I have not seen references with 120-130 deg (I believe that is incorrect). Please give a source.

Strasburger (talk) 20:35, 27 March 2021 (UTC)

The entire second paragraph of "Humans and Animals" is explicitly talking about "visual field". One specific sentence: "Humans have a slightly over 210-degree forward-facing horizontal arc of their visual field." At this point I don't know whether Field of View or Visual Field is the term which refers to "centrally focused eye positions" measurements, but whichever it is, the talk about "Visual Field" should be in the "Visual Field" article, not the "Field of View" article. LordQwert (talk) 17:51, 15 April 2021 (UTC)

The section Humans and animals is about the FoV of humans and animals from what I can see. The distinction between FoV and VF is often not clear cut (think of animals that have no eye movement). So just removing the content will not work.

For the 210° figure, I have added "(without eye movements)" so that it is not ambiguous. With eye movements allowed, it will be slightly larger but I have no reference for how much. Strasburger (talk) 10:19, 16 April 2021 (UTC)

I agree, btw, that much more should be said about the FoV or visual field for different species but this is a thorny issue because much of what is floating around on this matter is of dubious quality. Strasburger (talk) 10:27, 2 May 2021 (UTC)

Panoramic image at bottom of article is misleading

The image at bottom of page is misleading as it does not properly illustrate the topic. I have removed one sentence (improper description of image process and content). The image is is a stitched together composite of multiple original images mapped onto a distorted plane to give an illusion of the edge of a fish-eye lens effect at the apex of sky dome. The image is striking but confusing. I suggest the image be removed until a better example is found. Perhaps a panoramic image with superimposed lines that mark of binocular and peripheral fields and the points at which a humans head must be turned to bring additional areas into view.

— Neonorange (talk to Phil) (he, they) 08:45, 3 March 2022 (UTC) —

The image is indeed misleading: it has nothing to do with human or animal vision. Perhaps it is a left-over from previous sections on equipment like cameras or telescopes etc? Adding markers for aspects of human vision will make it even more confusing (since the concept of the FoV is not terribly well defined for humans). So I agree the image should be removed from the section on human and animal vision. Perhaps it could go to the astronomy section? Or, as a first step, be moved to the talk page (but then better put the explanatory sentence back in, to know what it was intended to show, namely the hypotheticl FoV of the entire telescope, including something like camera movements). Strasburger (talk) 13:14, 3 March 2022 (UTC)

Perceived Size

In the edit of 4 Aug. 2023, some information was moved from “Angle of view (photography)” to here (FoV), among it a section on perceived size. The latter, unfortunately, is ill-conceived, transporting the popular myth that angular size determines perceived size. It is further unrelated to the field of view since that refers to the overall size that is seen, not to its content. I therefore deleted the section in the article and moved it back to the “Angle of view (photography)” talk page, in case somebody wants to do something with it. Strasburger (talk) 11:12, 8 August 2023 (UTC)