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Tepp
25-05-2017, 16:28
The problem with all these FOV calculators and all these "proper" and "mathematically correct" values is the assumption that the FOV setting in the game should be equal to the angle of your view to your monitor. This usually explained as the window you are looking through. So the field of view (FOV) should depend on distance you are standing from this window.

But, THIS IS WRONG !!!

Imagine you are looking at a 30x40cm photograph hanging on the wall in front of you. The picture is taken with some standard camera with standard lens, which has it's own parameters - focal length, field of view, frame size, and many other.

Now try to step back few steps. Then a few more. Did the FOV on the picture change? Think of it? Does it?

The answer is NO!

The same is with the games. You are looking at the PICTURE, and the FOV does not depend on the distance how far you are sitting/standing from it.

Let me introduce a new term from world of photography, which is tightly related to all the lens and optical parameters - and the term is PERSPECTIVE.

Every experienced photographer knows about it. And he (she) knows that the wide-angle lenses (have wider FOV) extends the perspective - distance between the objects in the field of the picture looks increased comparing to a "normal" perspective. But, the telephoto lenses (narrow FOV) compress the perspective, so the objects look closer to each other and to a viewer than they are "normally". Both these cases are called PERSPECTIVE DISTORTION.

Actually, when you are changing the FOV in the game (actually this should be called AOV - Angle of View, or Angular Field of View), two things happen and they are tied togehter:

1. The field of view (proper FOV term) changes - the visible part of the image, so you can see more - that's why most of the users set this higher, so they see more of the scene.
2. The perspective also changes. And if you set too high or too low, you've got the perspective distortion.

So actually we want the "NORMAL" perspective, to avoid the perspective distortion, right?

I'm a photographer, so I know that the "normal" lens, which does not have (or have minimal) perspective distortion is the f=50mm lens (f=focal length, on full frame camera with 24x36mm frame size, 3:2 aspect ratio). So we can calculate the "normal" field of view (horizontal angular FOV) for 16:9 image, which is 45 degrees.

This will give you the "natural" view without the perspective distortion. But in real life this view will be too narrow and pretty limited for driving, so it's usually can be expanded to a moderate wide-angle view (horizontal 50-70 deg). The more you change it from "normal", the wider picture will be, but more perspective distortion you will get.

And remember: the FOV is NOT related to a distance you are sitting from the screen! This is wrong assumption.

References:
https://en.wikipedia.org/wiki/Perspe..._(photography)
https://en.wikipedia.org/wiki/Angle_of_view
https://en.wikipedia.org/wiki/Normal_lens
https://www.nikonians.org/reviews/fov-tables
http://themetalmuncher.github.io/fov-calc/

P.S. Sorry for my English.

bradleyland
26-05-2017, 06:02
Perspective and FOV (as implemented in sim racing games) are related concepts, but are not the same. When you view a photograph, there is no expectation that objects will appear to be "actual size". In sim racing, that expectation is not just present, it is implicit.

I actually wrote this up for another forum, but you may find it useful:

FOV is both subjective (preference) and objective (factual).

The size of objects, their location within your view, and the translation (movement) of objects across your screen are all dictated by simple geometry. That is to say, for a given screen size and viewing distance, the correct field of view will render objects at the same size as if you were sitting in an actual car. Likewise, objects will translate (move) through your view in the same proportions as real life. This is fact, not preference.

Unfortunately, many console gamers are playing on a couch (more than 1 meter away) with a reasonably sized television 36"-55". If the geometry of your viewing setup doesn't work well for optimal FOV, you have to compromise. That's where preference comes in: how much are you willing to compromise?

To get a sense of how poor the geometry of a typical couch setup is, just imagine someone built a black box around a car. The wall in front of you is the same distance as your TV. Now imagine that someone cut a hole in the wall that is the size of your TV. It's like viewing the world through a keyhole.

In order to see more, you have two options: make the window larger (bigger TV), or move closer to the window (sit closer to the TV). When you look at the geometry, something interesting is revealed. Moving closer yields much greater improvement than making the window larger. This is why it is so important to sit as close as possible to your TV.

Tepp
26-05-2017, 07:53
bradleyland,

Yes you are right, Perspective and FOV are different concepts, but they are tightly tied together.

If you increase the FOV, the perspective expands, so the distant objects appear further than they actually are. If you decrease FOV, the perspective contracts, so the objects appear closer than they actually are (like in binoculars).

About "actual" size of the objects - there is nothing to do with FOV, just buy a larger TV or sit closer. Or use the VR ... :)

I'm just trying to tell that if you sit further, you don't have to change the FOV accordingly. It's independent of the viewing distance.

hkraft300
26-05-2017, 08:10
In order to see more, you have two options: make the window larger (bigger TV), or move closer to the window (sit closer to the TV). When you look at the geometry, something interesting is revealed. Moving closer yields much greater improvement than making the window larger. This is why it is so important to sit as close as possible to your TV.

Option 3: move the wall :)
I've noticed many 3-screen setups using dash/bonnet cam.

MaximusN
26-05-2017, 09:05
Option 3: move the camera :)
I've noticed many 3-screen setups using dash/bonnet cam.

I prefer a closer monitor/TV(my 32" is as close to my wheel as possible). You cannot move the camera forward without also moving the side view forward. And the left/right view is all-important in knowing where your opponent is. You might even say that you're giving back some of the extra spatial-awareness you bought the 3 monitors for...

hkraft300
26-05-2017, 10:01
I thought the same, seeing others' 3-screen view.

I sit ~a meter away from a 42". As close as I can get.
But I run Hugh fov to compensate and have better side vision.
Sure the view is slightly warped. Compromise.
Until VR :)

bradleyland
27-05-2017, 01:40
bradleyland,

Yes you are right, Perspective and FOV are different concepts, but they are tightly tied together.

If you increase the FOV, the perspective expands, so the distant objects appear further than they actually are. If you decrease FOV, the perspective contracts, so the objects appear closer than they actually are (like in binoculars).

About "actual" size of the objects - there is nothing to do with FOV, just buy a larger TV or sit closer. Or use the VR ... :)

I'm just trying to tell that if you sit further, you don't have to change the FOV accordingly. It's independent of the viewing distance.

The further away you are, the smaller your TV appears, and by proxy, the objects in your screen. This necessitates a change in FOV, which effectively magnifies what is displayed on screen.

In order to maintain 1:1 scale, display size, viewing distance, and FOV must all be balanced. You might be tempted to make the argument that you don't care about the size of objects on screen, but because the game is projecting 3D objects onto a 2D plane, correct FOV is required for translation to occur correctly. This is actually the most significant impact, because it relates to our ability to judge distance to objects; i.e., depth perception.

A perfect display would be hemispherical, but because most displays are flat, you'll always have some degree of distortion.

bradleyland
27-05-2017, 01:43
Again, this all relates to the objective aspect of FOV. Subjectively, compromise is a fact of life. It all gets rather academic, but IMO, it's important to be accurate in our assessment of what is objectively accurate, and what we do out of compromise.

inthebagbud
27-05-2017, 06:21
I need to ask here as FOV is a little soapbox of mine in the game. On xbox FOV settings only move your position in the car (you get nearer the windscren or further from the windscreen) they do not alter the distance too objects outside of the car.

I have always presumed this is incorrect as FOV should alter the distance too objects outside of the car .

Am I correct?

And if so I assume pc and ps4 work correctly it's just xbox that doesn't work

Fanapryde
27-05-2017, 07:30
I thought the same, seeing others' 3-screen view.

I sit ~a meter away from a 42". As close as I can get.
But I run Hugh fov to compensate and have better side vision.
Sure the view is slightly warped. Compromise.
Until VR :)
Triple 27" monitors angled at 45, all three about 54cm from my eyes (which is as close as I can physically get them as I need to have the middle of the screen at eye height).
I don't remember right now what value I use for FOV, but I can change that on the fly if wanted.
Apart from the warped view in the side monitors (which is not going to be an issue in pCars2, since we will have proper triple screen support) it is great.
Tried VR three times now, got upcoming nausea after about 10 minutes each time, so I ruled that out (for several other reasons too).

About a year ago I made a cardboard frame representing the bezels of the triples and took it inside my car to check what I see IRL and I must say that the view in my rig is pretty close (apart from the side screens with the warped view and huge mirror on the drivers side - not even seeing the one on the other side).
I only use cockpit view with my real wheel matching the place of the disabled virtual wheel, and I can rely on the dash instruments/gauges.

bradleyland
27-05-2017, 08:12
I need to ask here as FOV is a little soapbox of mine in the game. On xbox FOV settings only move your position in the car (you get nearer the windscren or further from the windscreen) they do not alter the distance too objects outside of the car.

I have always presumed this is incorrect as FOV should alter the distance too objects outside of the car .

Am I correct?

And if so I assume pc and ps4 work correctly it's just xbox that doesn't work

That is very strange. On PS4, we can use a keyboard to press ctrl k and adjust FOV in real time. It doesn't "save", but you can really see the effect it has on perspective. It definitely scales objects outside the car. The track width at a given distance is what's most obvious. I'm wondering if you aren't just struggling with a perception issue though. Everything scales together, so the effect is kind of hard to pinpoint when you can't compare it live.

hkraft300
27-05-2017, 08:27
On xbox FOV settings only move your position in the car (you get nearer the windscren or further from the windscreen)
Am I correct?


Are you sure you're not adjusting the seat?
Adjusting FoV shouldn't change your virtual position in the virtual car.

inthebagbud
27-05-2017, 11:28
That is very strange. On PS4, we can use a keyboard to press ctrl k and adjust FOV in real time. It doesn't "save", but you can really see the effect it has on perspective. It definitely scales objects outside the car. The track width at a given distance is what's most obvious. I'm wondering if you aren't just struggling with a perception issue though. Everything scales together, so the effect is kind of hard to pinpoint when you can't compare it live.

Yes ctrl k works on xbox as well but only adjusts your position in car nothing changes externally


Are you sure you're not adjusting the seat?
Adjusting FoV shouldn't change your virtual position in the virtual car.

This is a video showing that fov doesn't work and also fov speed sensitivity and look to apex doesn't either on the xbox.

Look to apex used to so did sensitivity but as far as I can remember fov only ever changed your position in car.


http://youtu.be/OmCkvy1cwkY

Mad Al
27-05-2017, 11:45
Yes ctrl k works on xbox as well but only adjusts your position in car nothing changes externally



This is a video showing that fov doesn't work and also fov speed sensitivity and look to apex doesn't either on the xbox.

Look to apex used to so did sensitivity but as far as I can remember fov only ever changed your position in car.


FOV Test* https://youtu.be/OmCkvy1cwkY

How do you say that shows FOV isn't working ? First run is with a stupidly small FOV so every corner looks like a hairpin and the second run shows a more normal setting where the corners look longer.. just as expected

Roger Prynne
27-05-2017, 12:19
Looks like it is working as intended to me, even the look to apex is working in the first half of the vid.

inthebagbud
27-05-2017, 12:53
How do you say that shows FOV isn't working ? First run is with a stupidly small FOV so every corner looks like a hairpin and the second run shows a more normal setting where the corners look longer.. just as expected


Looks like it is working as intended to me, even the look to apex is working in the first half of the vid.

H''mm I will have to recheck when at machine as mobile at present so can't double check maybe I am missing something here :)

Silraed
27-05-2017, 13:18
Checked in game to be sure (on PC) and your video is working properly. The main difference of the larger FOV is the "funnel" effect, so if you park the car on a pit straight and change your FOV from one extreme to another the pit buildings near the edge of the screen will seem to stretch out longer or appear shorter. The more obvious effect is that the road appears far narrower in the distance with a wider FOV.

bradleyland
27-05-2017, 20:27
Looks like it's working correctly to me. The reason you appear to move forward in the car is because you see less of the car as the FOV narrows.

inthebagbud
29-05-2017, 06:10
Thanks for the replies which are appreciated and it appears I was wrong.

I think what was throwing me ws the fact that I moved in car , I expected the view outside of the car to change but for me to remain static in the car. When I have tried fov in the past and have moved towards the windscreen I have been u bale to drive so I gave up wth it.

Once you have changed fov canny then alter your position in the car using ctrl k or will this alter the fov as well?

Luckily bank holiday in UK so full day practicing coming up :D

TorTorden
29-05-2017, 09:45
Thanks for the replies which are appreciated and it appears I was wrong.

I think what was throwing me ws the fact that I moved in car , I expected the view outside of the car to change but for me to remain static in the car. When I have tried fov in the past and have moved towards the windscreen I have been u bale to drive so I gave up wth it.

Once you have changed fov canny then alter your position in the car using ctrl k or will this alter the fov as well?

Luckily bank holiday in UK so full day practicing coming up :D

You never move in the car, you just see a lot less of it because of a narrower field of view and for a myriad of other options this means getting a zoomed view.

Nobody would consider playing using a 30 FOV either so why would you?
The goal for most is to get the widest FOV possible so we can actually see things.

inthebagbud
29-05-2017, 10:28
You never move in the car, you just see a lot less of it because of a narrower field of view and for a myriad of other options this means getting a zoomed view.

Nobody would consider playing using a 30 FOV either so why would you?
The goal for most is to get the widest FOV possible so we can actually see things.

I'm not saying I wanted a fov of 30 however I wanted to move some of the world nearer to me but did not like or understand why my position in the car changed , which has now been explained, but for me I do not like that when I bring the FOV in (smaller) that I end up basically with my face against the dash.

I want to keep my position in the car but bring the outside world nearer to suit my reaction times and perception

bradleyland
29-05-2017, 22:13
Not possible, because FOV adjustments affect the entire field of view, not just outside the car. Your position in the car isn't changing, you're just seeing less. I know it seems counter-intuitive, but that's just how FOV works. It's best to find a balance. I used this FOV calculator (http://www.projectimmersion.com/fov/), but bumped mine up a few degrees so that I can see a bit more of the cockpit... which is what pretty much everyone gaming on a TV does.

The most important thing you can do is to sit closer to the television. Imagine the TV screen as a frame that you're looking through while sitting in your car. Imagine if you hung that frame 6 feet in front of you. It would be outside the car. More than likely, it would be past the hood! That's why it's so important to sit close to the display. It's like moving the frame closer (hopefully, inside the car), thus you can see more of the inside of the car.

inthebagbud
30-05-2017, 05:53
Not possible, because FOV adjustments affect the entire field of view, not just outside the car. Your position in the car isn't changing, you're just seeing less. I know it seems counter-intuitive, but that's just how FOV works. It's best to find a balance. I used this FOV calculator (http://www.projectimmersion.com/fov/), but bumped mine up a few degrees so that I can see a bit more of the cockpit... which is what pretty much everyone gaming on a TV does.

The most important thing you can do is to sit closer to the television. Imagine the TV screen as a frame that you're looking through while sitting in your car. Imagine if you hung that frame 6 feet in front of you. It would be outside the car. More than likely, it would be past the hood! That's why it's so important to sit close to the display. It's like moving the frame closer (hopefully, inside the car), thus you can see more of the inside of the car.


So of after Altrincham fov is this then affected by seat position or ctrl k changes.

And as have people who know what they are taking about any chance you could review my video from early and see if I am using the fov speed sensitivity correctly as again I am under the believe that this doesn't work properly ?

Thanks for your patience

bradleyland
31-05-2017, 20:36
So of after altering fov, is this then affected by seat position or ctrl k changes.

Yes and no. When you move the seat forward and backward, your FOV isn't affected, but you'll still notice you see less/more of the car. To understand why, imagine looking through a box, which limits your field of view. Now step forward. The objects at the edge of your view will move out of sight, because they are now "behind" the edge of your visible area. Likewise with ctrl-k settings for camera movement. Keep in mind that numpad +/- actually changes FOV, so that's a solid "yes".

This happens in real life as well, but it happens at the periphery of your vision, so you don't notice. You can perform a simple experiment to see the effect more easily

- Close one eye
- Cup your hands around your open eye in a sort of tube shape
- Move forward and backward, but keep your head straight ahead
- Move left and right, but keep your head straight ahead
- Tilt your head
- Notice how things move in and out of view

That's like moving the camera.

Using the same experiment:

- Increase the size of the opening in your cupped hands
- Now decrease it

That's like changing FOV.

The key thing to remember is that the game uses a "camera" system. That is to say, your view is provided by a virtual "camera" in the game world. Whatever the camera "sees" in 3D is projected in 2D on to your display. That's why changing FOV looks so strange; because you're seeing changes in a projection, which not only changes what you see/don't see, but distorts the view as it is flattened to 2D.

In the experiment using your hands, a tube, a window frame, or any other mechanism, you're only limiting what you see. Our perception of sight doesn't include the ability to "stretch" a limited field of view to our entire perceptive FOV, so we can't really duplicate what the 3D engine does.


And as have people who know what they are taking about any chance you could review my video from early and see if I am using the fov speed sensitivity correctly as again I am under the believe that this doesn't work properly ?

It looks like it's working normally to me.


Thanks for your patience

Not a problem. Questions are how we learn :)

inthebagbud
01-06-2017, 05:41
@bradleyland thanks again for the reply and I can play now with ctrl k and fov :yes:

On the speed sensitivity what are you seeing that indicates ut works as I assume the settings mean that at a certain low or high speed the actual fov will be set % larger or smaller than that which you have set. . I didn't see any such change in the fov.

I am just wondering if I have become used to the changes and whereas when I first used them they seemed exaggerated as I had never seen the effect before , now that I have used the game for a couple of years the changes do not seem exaggerated and just happen without me really noticing

If that makes sense

bradleyland
01-06-2017, 13:57
@bradleyland thanks again for the reply and I can play now with ctrl k and fov :yes:

On the speed sensitivity what are you seeing that indicates ut works as I assume the settings mean that at a certain low or high speed the actual fov will be set % larger or smaller than that which you have set. . I didn't see any such change in the fov.

I am just wondering if I have become used to the changes and whereas when I first used them they seemed exaggerated as I had never seen the effect before , now that I have used the game for a couple of years the changes do not seem exaggerated and just happen without me really noticing

If that makes sense

Ah, sorry. I was more focused on the FOV change to make sure it was reflected correctly. To be honest, the speed sensitivity stuff is very subtle. You can move the settings so that it's more extreme, but that obviously makes things a little goofy. I never really mess with the settings, because I don't really want it to be noticeable, if you know what I mean. I don't necessarily mind if it happens; I just don't want to notice.

Tepp
06-06-2017, 12:34
The key thing to remember is that the game uses a "camera" system. That is to say, your view is provided by a virtual "camera" in the game world. Whatever the camera "sees" in 3D is projected in 2D on to your display. That's why changing FOV looks so strange; because you're seeing changes in a projection, which not only changes what you see/don't see, but distorts the view as it is flattened to 2D.

Exactly!



In the experiment using your hands, a tube, a window frame, or any other mechanism, you're only limiting what you see. Our perception of sight doesn't include the ability to "stretch" a limited field of view to our entire perceptive FOV, so we can't really duplicate what the 3D engine does.


We can! Just take the photo camera with a zoom lens ... :)

Focal Length affecting perspective distortion:
http://imgur.com/gallery/yNcPX

Mascot
06-06-2017, 12:58
Very interesting discussion..! :encouragement:

Olijke Poffer
06-06-2017, 13:07
Exactly!



We can! Just take the photo camera with a zoom lens ... :)

Focal Length affecting perspective distortion:
http://imgur.com/gallery/yNcPX

Cool images and dito example to show things.. nevertheless I keep my FOV set to 46 on my 55inch screen. Love it this way..

inthebagbud
06-06-2017, 21:29
Cool images and dito example to show things.. nevertheless I keep my FOV set to 46 on my 55inch screen. Love it this way..

Wow 46 is that in car view and does that mean you don't see any of the car dash and exterior mirrors as you are so far forward

bradleyland
06-06-2017, 23:52
Wow 46 is that in car view and does that mean you don't see any of the car dash and exterior mirrors as you are so far forward

Remember, he hasn't moved forward, he has just narrowed his view ;) Imagine looking through a narrow tube.

bradleyland
06-06-2017, 23:59
Exactly!



We can! Just take the photo camera with a zoom lens ... :)

Focal Length affecting perspective distortion:
http://imgur.com/gallery/yNcPX

I love this Imgur gallery. Any time someone asks me why their camera-phone photos of cars look so horrible, I try to explain to them that it's the focal length. They always look at me funny :) That's also why I love the larger iPhone with the dual-lens camera. You get two actual, different focal lengths. It's so hard to explain to people that zooming on a camera phone does not eliminate perspective distortion, you're just cropping the photo. Since most camera phones have an focal length (35mm equivalent) of around 28mm, you get the usual 35mm distortion, which makes everyone's face look like it's poking out a bit. The telephoto lens on the iPhone 6/7 Plus is about 57mm (35mm equivalent), so you get a much more natural looking portrait. I prefer to shoot portraits at ~85mm, but I'll take 57mm over 28mm.

hkraft300
07-06-2017, 01:37
Since most camera phones have an focal length (35mm equivalent) of around 28mm, you get the usual 35mm distortion, which makes everyone's face look like it's poking out a bit.

But first let me take a selfie...

Olijke Poffer
07-06-2017, 05:10
In car view indeed. I use a keyboard to position myself further backwards just befor the cam is entering the chair so to speak. This way I see a good part of the dashboard. And in most cars also a bit of the side mirriors.


An example of the FOV on my setup. This is in a BMW Z4 GT3 so indeed no left and right side mirriors to see. In an openwheel car I can see the mirrors. Happy with my Crewchief app used for spotter. ;)


https://youtu.be/bHivOeYj4J8

And as seen as from my point of view. Sorry for the darkness. But closed blindings and recorded with a cellphone..

https://youtu.be/sj9_j9BiEpA

inthebagbud
07-06-2017, 12:21
In car view indeed. I use a keyboard to position myself further backwards just befor the cam is entering the chair so to speak. This way I see a good part of the dashboard. And in most cars also a bit of the side mirriors.


An example of the FOV on my setup. This is in a BMW Z4 GT3 so indeed no left and right side mirriors to see. In an openwheel car I can see the mirrors. Happy with my Crewchief app used for spotter. ;)


https://youtu.be/bHivOeYj4J8

And as seen as from my point of view. Sorry for the darkness. But closed blindings and recorded with a cellphone..

https://youtu.be/sj9_j9BiEpA

Thanks for the videos its nice to see rather tahn read what others POV looks like ;)

Time to have a play a bit more with these settings

Thanks guys

honespc
07-06-2017, 20:43
I thought the same, seeing others' 3-screen view.

I sit ~a meter away from a 42". As close as I can get.
But I run Hugh fov to compensate and have better side vision.
Sure the view is slightly warped. Compromise.
Until VR :)lower the default 80 folv or the higher you have set it from there down to 60 or so, and witness your best old lap times improved by a second and a half or more, as well as increased vehicle control with better reaction times

hkraft300
08-06-2017, 03:38
Got it at 70.
Little distorted. But I see what I need.
I've tried 60. Couldn't see much of the dash or my sides (need more buttons for seat adjustment).
Even Monaco felt spacious.