11 ms·

TV Size-to-Distance Calculator and Science

109 points by nkjoep 6y ago

jdashg 6y ago
I know that the value here is that it saves people effort to pre-digest this knowledge, but oh man this is the stuff that high school math definitely taught us to solve. Heck, maybe this makes it a useful interview question scenario?
- TeMPOraL 6y ago
  > oh man this is the stuff that high school math definitely taught us to solve And if only it taught us on problems like this, people would be more interested in and able to apply this knowledge.
- iso1631 6y ago
  The key bits of information you don't have by default are 1) The field of view that's recommended - 30 degrees (SMPTE) or 40 degrees (THX) 2) The angular resolution of a 20/20 eyeball (1/60th of a degree) The rest of it you can calculate yourself from basic trig.
- driverdan 6y ago
  > Heck, maybe this makes it a useful interview question scenario? Only if the job requires making these types of calculations.
BlueTemplar 6y ago
When it comes to visual acuity for TV watching, doing calculations while basing yourself on their suggested '20/20 vision'=1/60 of a degree, is probably wrong (on average) : https://www.homecinemaguru.com/can-we-see-4kuhd-on-a-normal-sized-screen-you-betcha/ https://www.homecinemaguru.com/can-we-see-4kuhd-on-a-normal-... (The real limit seems only to start around 310 pixels/degree !)
- iso1631 6y ago
  That would suggest with the naked eye you could look at the moon and pick out features about 20km wide https://skyandtelescope.org/observing/how-to-see-lunar-craters-with-the-naked-eye102820152810/ https://skyandtelescope.org/observing/how-to-see-lunar-crate... "At 0.8′ (arcminutes) across, the crater alone hovers at the naked-eye limit" Which seems to back the the c. 1/60th idea. Judging the resolution of an eye is a subjective process, not least beacuse of the relative sensititivty and density of rods and cones at different parts of the eye.
  - BlueTemplar 6y ago
    Exactly, 'subjective', the criteria the NHK used is 'sense of realness', not 'being able to consciously pick out features'.
trabant00 6y ago
Glad to see this get some exposure. It always kills me when people buy expensive 4k, curved, HDR, etc 50" TVs and sit over 10 feet away from them. (127 cm diagonal and over 3m away for Europe) You just threw your money away. Another thing is when you plan your sofa and TV furniture. Having over 10ft/3m (a common occurrence in homes) means you will need 100 inch screen for a cinematic experience, which means having lots of money or a projector, which brings a lot of problems itself. My personal setup is 6.5feet/2.5m 65 inch diagonal 1080p plasma Panasonic Viera from 2007. Everybody who hears about this thinks it's way too big for that close. But when guests ask for the specs of what they find an impressive picture in person they are always shocked to find it's "obsolete" technology. EDIT: as people dispute the real distance you can notice 4k vs 1080p, you don't need to trust any graph. Get close enough to your TV to notice individual pixels, then back away a little bit until you can't. That's the distance and I bet you will find it a lot close than you would think.
- HPsquared 6y ago
  It's a compromise between spacious living quarters (Feng Shui), and a cinematic experience when watching the TV.
  - iso1631 6y ago
    Cinema means you want 30-40 degrees, but once you've fixed your screen size and your distance, you can then work out if 4k is worthwhile over 2k (or 8k over 4k) Of course this all falls down because it them comes down to availability, other features (number of hdmi ports, "smart" options, power use), and "4k" tends to also mean things like HDR, which is worthwhile (with the right source) no matter the screen.
  - driverdan 6y ago
    > It's a compromise between spacious living quarters (Feng Shui) Feng Shui is not "spacious living quarters", it's pseudoscience nonsense.
- BlueTemplar 6y ago
  I wish I could buy a FullHD HDR TV...
mankyd 6y ago
Recently upgraded from a 1080p 40" TV to a 4k 55". According to this, at ~12ft away, we should have bought an 85" TV?! That's crazy and dumb. Or rather, a misrepesentation. This article states that we _could_ get away with up to an 85" TV. It is only at that limit that we'd start to see "imperfections" as they call it. I don't want to see imperfections. I also don't need a TV that will take up my whole field of view while bathing me in light. The 55" we have already feels quite large, much sharper, and is brighter. This article may be interesting from an academic point, but people shouldn't misconstrue this to think they should be getting a bigger TV. Get a TV that fits your space and feels comfortable. Bigger is not always equal to better.
- hundchenkatze 6y ago
  I think it's useful outside of an academic thought experiment. It hasn't encouraged me to get a bigger tv, quite the opposite. My takeaway isn't that I need a bigger tv, it's that I can get by with a smaller screen and lower resolution.
  - mankyd 6y ago
    Except that at the very top is a slider that gives you a recommendation of screen distance to screen size. I think a lot of folks will encounter this and stop there.
    - hundchenkatze 6y ago
      Maybe, but the article is still useful for people that read it in it's entirety.
- simlevesque 6y ago
  You missed the point.
  - mankyd 6y ago
    What is the point then? I feel as though lots of people will read this and say "My couch is 10+ feet from my tv. This states that I _need_ to get a giant tv".
jb1991 6y ago
I totally don’t understand what this chart is trying to expose. What is meant by the distance here?
- iso1631 6y ago
  Distance from eyeball to screen. There are 2 things this page shows, one is the size of screen you need relative on the distance you sit from it based on how much of your view you want it to fill, the other is what resolution the screen needs to be before you have no improvement. First decide what you want 30 degrees means you'll be able to focus on the picture, but it will fill your focus area, that's recomended by SMTPE 40 degrees is the "immersive" portfolio recommended by THX, you may lose some detail at the edge of the screen depending where you're looking. Then it's just a bit of trig to work out the size you need for the distance you are sitting (or vice versa), to match your preferred "fullness" Second is whether you'll benefit from more pixels. They base this on having 20/20 vision and your optical resolution being 1 arc-minute (1/60th of a degree). For comparison the moon is about 30 arc minutues wide. Seems reasonable to me, if I take a picture of the moon and shrink it to 30px by 30px, I feel it's on par with what I can see in real life. Then it's just more trig to work out how many pixels you need for a given size/distance combination. A 20" screen that's 10 feet away, you won't be able to tell the difference between SD and HD. A 40 inch monitor 2 feet away and you'll benefit from going higher than 4k. (This assumes a 16:9 aspect ratio).
  - BlueTemplar 6y ago
    Except they are probably wrong... https://news.ycombinator.com/item?id=26088890 https://news.ycombinator.com/item?id=26088890
    - iso1631 6y ago
      Well they're quoting a definition of "20/20" vision from a researched article on wikipedia https://en.wikipedia.org/wiki/Visual_acuity https://en.wikipedia.org/wiki/Visual_acuity Which states "At 6 metres or 20 feet, a human eye with that performance is able to separate contours that are approximately 1.75 mm apart" Which I assume comes out at 1/60th of a degree. You could argue that measurement is in fact wrong, or that there's something happening subconciously, but their point is that based on accepted viewpoints that someone with 20/20 can't determine the difference between two contours 1mm apart from 6 metres, you don't need to display them. NHK by the way put a lot of money into developing 8k technologies, I saw it about 10 years ago. I was more impressed with the 120fps stuff than the higher resolution. YMMV.
apercu 6y ago
According to this I'm doing it wrong. And I don't care.
Navarr 6y ago
Would be nice if it threw in a "how far up the wall should this be" number
- kec 6y ago
  There’s no formula to spit out a handy chart for that. Center of the screen should be eye level for an adult sitting on your couch, ballpark 3’/1m for most setups.
- sul_tasto 6y ago
  just not too high... https://www.reddit.com/r/TVTooHigh/ https://www.reddit.com/r/TVTooHigh/
BuildTheRobots 6y ago
Quick point of note regarding TV resolution requirements: I've got an old Samsung 45" screen that's only 1080p. Usually films and other media look great on it and I was pretty convinced I didn't need a higher resolution. Last night I tried playing back some filmed-in 4k drone footage which ended up looking impressively awful. It was sharp, but lots of pixel level brightness noise changing from frame to frame, which looked grainy and was extremely distracting. I can only assume it's the way VLC or my graphics card are downsampling to display it at 1080, but it was annoying enough I'm now thinking of a new 4k TV at some point in the future. TLDR: Your source media might make a big difference.
SloopJon 6y ago
As for wasting your money on a 4K set vs. a full HD set, it almost isn't even a choice anymore. The "budget" 4K recommendation at RTINGS is about $500. Also, although it is mentioned in the text, keep in mind that not all content is high-bitrate 4K: Cable TV? Probably compressed 1080p or 720p, depending on the channel. If it's Comcast/Xfinity, they may even squeeze three channels into the bandwidth of two. Streaming? Compressed 1080p, with the occasional 4K. Old (but not that old) Blu-rays? 1080p. If you're sitting in your leather club chair, Oppo UHD Blu-ray remote in one hand and a glass of '92 Screaming Eagle Cabernet in the other, then sure--slide your chair into the sweet spot at the optimal distance per these charts. Don't get me wrong: when I replace my ten year-old Sony, it's going to be with the biggest LG CX or C1 OLED my wife lets me get. Just realize that trigonometry isn't the whole story.
- cainxinth 6y ago
  There’s still good, old fashioned antennas that deliver much less compressed video than cable.
  - DavidPeiffer 6y ago
    About a week ago I heard about NextGen TV for the first time (ASTC 3.0). They're starting to roll out across the country will bring 4k content over the air. Not sure how compressed it will be, but I remember how revolutionary it was to switch to the digital OTA channels with a converter box many years ago. www.cnet.com/google-amp/news/watch-free-4k-tv-broadcasts-with-an-antenna-nextgen-tv-comes-to-more-cities-in-2021-atsc-3-0/
ksec 6y ago
Oh I am so glad this is on HN front page so I get to ask the question. Why 8K? I think people should try this at home. THX recommended Viewing Distance for cinema experience is 40 Degree. That is like sitting in the first few rows in a cinema that makes me sick watching movies. The maths that works for a 16:9 Display, 55" (inch) would be 5.5 Feet, 60" would be 6 Feet. Divide the display inches by 10 and change the unit to Feet. And assuming you are even somehow comfortable with this distance in everyday usage, you wont notice the pixel on a 4K TV with a 20/20 vision, what Apple calls it "Retina". For a 50" 4K TV it becomes "Retina" at a viewing distances of 39 inches. Some would argue 20/20 Visual Acuity is antique. With 20/15, Retina starts at 52 inches. That is still below the THX recommend viewing distance of 5.5 Feet, or 66" on 50" Display. What about the 20/10! Well that would be 78inch, so yes they could see those pixel. But that is only viewing at 40 degree angle. If you view it in what most would consider normal of 30 degree, you would be sitting at 6.8 feet or ~82inch away from the TV. I.e You still wont see those pixel. Also note we dont test moving object in visual acuity test. You are watching "Moving Pictures" on a TV. Not watching a single pixel. And if, in any case we need to optimise for the 5% with 20/10 vision that prefer to sit in the front row of the cinema. We could have went with 5K! And despite only 1K increase which seems very small, that is going from ~8M pixel to ~15M pixel. We would have room to spare even for the remaining 5% use case. And if we are so paranoid and need even more headroom. Even 6K will do. Instead we went for 8K; ~33M Pixels. The amount of bandwidth, computational power, compression, storage. We could have use those for higher frame rate when needed, 10bit colour accuracy by default or high quality colour profile. Instead we spent it on Pixel. And before someone jump in saying they could tell the difference between 4K and 8K. Remember the current marketing term of 8K Requires mandatory support of HDR and brightness level. Something 4K could do without. What you think of 8K being better may have nothing to do with pixel density at all. So apart from Sales and Marketing department pushing for it, ( along with Japanese government pushing it for Olympics ) like the days of Intel CPU pushing for Mhz. For someone who has no expert knowledge on the subject and merely an outsider, let me ask the question again. Why 8K?
- StrictDabbler 6y ago
  Moire effects. Modern TV sales demo videos are chosen for the exact kind of thing you start to see when the resolution gets higher. Footage of the ocean waves, schools of fish, flocks of birds. Moire effects and screengating are way larger than any one pixel. They make ripples and lumps in the image. You get used to the way hair looks on any generation of TV but it's nothing like "imperceptible" distortion. You can stand dozens of feet from an 8K, a 4K, and a 1080 TV and tell the difference when the image is of many tiny objects moving across each other. Grass. Leaves. Sand. A tiled floor viewed from an angle. You know, rare stuff like that.
mercora 6y ago
when reading about these considerations i always wonder if it really matters at which point i could discern single pixels from one another. i think there is more to it when we are talking about what we can see in the image. maybe we wont be able to benefit in the way that we see less of the pixel raster but i feel like having more details will benefit image clarity non the less. even if it is impossible to effectively discern the pixels the combination of them might still affect what i can see....
willis936 6y ago
I recently tried to appropriately set the FOV of first person shooters to match the FOV that the screen actually took up. I found that most games would not let me set my FOV that low, even when I was 1-2 feet away from a 24” monitor. It seems strange that it is given that people want a wider FOV than is natural. It gives a competitive advantage in the majority of scenarios, but I’m surprised more people don’t stop and think “this looks off”.
- aidenn0 6y ago
  The wider FOV makes me nauseous. Setting the FOV as narrow as possible lets me play FPS games. It took me a while to figure out why some games made me sick and others didn't. Turned out to be FOV.
  - spathi_fwiffo 6y ago
    Interesting. I think I have the opposite issue. I try to get FOV in to 85 - 110 range. Otherwise i feel sick (or i need to sit far back from the monitor, which i can't really do on PC).
- rozab 6y ago
  Why would you want to simulate the experience of looking through a small window from a few feet away?
  - willis936 6y ago
    To use a gamer buzzword: immersion. I usually play on PC. When I play games on my sofa (very narrow real life FOV) the issue is so pronounced that I feel like I’m on a treadmill. It pulls me out of the experience so much that I’d rather just play a different type of game.
- hammock 6y ago
  VR goggles. Turn 1-2 feet away into 1-2 inches away
zokier 6y ago
> The chart also shows that a 4k upgrade is not worth it if you are sitting more than 6' away and have a 50" TV. Your eyes won't be able to tell the difference. Doesn't the chart say exact opposite, the threshold for 50" 1080p is 6.3', so if your view distance is less than that (like 6.0') then 4k is worth it?
wing-_-nuts 6y ago
This has been on my mind a lot with the whole '4k gaming' push from the most recent consoles. 4k gaming just doesn't make sense for a lot of people. I have a 55" tv and sit 8.5' away from it. This TV is huge and dominates the room. I cannot reasonably have a larger tv or sit closer without ruining the usability of my livingroom. Most people simply sit too far away from to small of a TV to be able to tell 4k from 1080p. When people protest they can absolutely see a difference, what they're usually seeing is better color and contrast of newer tvs, not resolution. Even when it comes to PC gaming, 4k is often not all it's cracked up to be. According to OSHA, most people sit about 30" away from their monitor. This lines up nicely with the visual acuity distance for a 27" 1440p monitor. To reach the visual acuity limit for 4k, you'd have to sit 20" away. That's a lot closer than most people are comfortable with. Even a 32" model only expands it out to 25". That's within the realm of plausibility but another thing to keep in mind is viewing angles. The main theatre certification companies recommend anywhere from a 35-55 degree viewing angle. The visual acuity distance for 4k puts you at a whopping 60 degrees which is considered high for just consuming content, much less playing a game where you're expected to see everything happening on screen and react to it. TLDR: The hype of 4k for gaming is mostly just that. Most people would be far better served going for lower resolutions and higher refresh rates. The only people who really benefit from 4k are using it for productivity, coding, video editing, etc.
- Dylan16807 6y ago
  > a whopping 60 degrees which is considered high for just consuming content, much less playing a game where you're expected to see everything happening on screen and react to it. Consider that the game is probably rendering at least 90 degrees to squish down into that 60. Personally I sit back for content but I love to sit close for games, with the FOV set to max. The really important stuff fits in the middle of the screen, and outside of the middle I get near-peripheral vision instead of bezel and wall.
- ants_a 6y ago
  32" 4k monitor at a normal viewing distance (~30" seems like a good estimate without bringing out a measuring tape) is pretty comfortable for work at 100% scaling. At that distance 1080p video looks significantly worse when compared to 4k, although a large chunk of that may be due to bitrate.
aidenn0 6y ago
I got a mount that swings down from the wall. If you are going for a 40-degree view angle making the TV a foot closer is the same as making it 10" larger. It also has the advantage of going above furniture when not in use, but down at eye-level to the couch when in use.
PaulAJ 6y ago
Unfortunately this exhibits the usual confusion between pixel pitch and resolution, which makes it completely wrong. > Studies show that someone with 20/20 vision (or 6/6 in Europe) can distinguish something 1/60 of a degree apart. This means 60 pixels per degree [...] NOOOOO! "Resolution" is defined as the closest distance two dots can be while still appearing as two distinct dots. If you have two dots shown on adjacent pixels then you just see one big dot. You need the two dots separated by a pixel in order to see that there are two dots, so the resolution is half the pixel pitch. Worse yet, the two dots might be diagonal, so you need an extra factor of sqrt(2) in your resolution calculations. This means that the pixel pitch of a TV screen is 2 * 1.41 ~= 3 times its resolution. You need 180 pixels per degree if you have 20/20 vision, not 60. And it gets worse. Everyone knows that 20/20 vision is "normal". Well, not quite. 20/20 vision is the average without correction. Once you include glasses, 75% of people can actually see better than that, and some quite a lot better. So to be safe lets bump the pixel density up by another third, to 240 pixels per degree. That gives 7,200 pixels on a 30 degree screen.
- dharmab 6y ago
  Not to mention subpixel rendering and antialiasing, which can make a perceivable difference, e.g. text vs. video games.
- elchief 6y ago
  so how big a tv should I get?
- nonninz 6y ago
  So does this essentially mean that all those people who say things like "You don't need/can't distinguish 4K if your nose isn't touching the screen()" are wrong? I have always thought it was a strange thing to say. I can definitely see the difference between a 4K stream vs a 1080p one, even when the screen is much more far away than the recommended distance... () An hyperbole, obviously.
  - timpattinson 6y ago
    To be fair the difference in bitrate between 1080/4k is probably (in my opinion) a bigger difference than the pixel count, uncompressed 1080 looks pretty damn good. but yeah the "the eye can't see >20fps" or a certain dpi is definitely BS.
elchief 6y ago
moves couch closer to tv... still waiting for ATSC 3.0, and the darn NFL and any Canadian broadcaster to show games in 4K
m-p-3 6y ago
I guess I need a 90" TV now.

109 points by nkjoep 6y ago

I know that the value here is that it saves people effort to pre-digest this knowledge, but oh man this is the stuff that high school math definitely taught us to solve. Heck, maybe this makes it a useful interview question scenario?

TeMPOraL 6y ago
> oh man this is the stuff that high school math definitely taught us to solve And if only it taught us on problems like this, people would be more interested in and able to apply this knowledge.
iso1631 6y ago
The key bits of information you don't have by default are 1) The field of view that's recommended - 30 degrees (SMPTE) or 40 degrees (THX) 2) The angular resolution of a 20/20 eyeball (1/60th of a degree) The rest of it you can calculate yourself from basic trig.
driverdan 6y ago
> Heck, maybe this makes it a useful interview question scenario? Only if the job requires making these types of calculations.

BlueTemplar 6y ago

When it comes to visual acuity for TV watching, doing calculations while basing yourself on their suggested '20/20 vision'=1/60 of a degree, is probably wrong (on average) : https://www.homecinemaguru.com/can-we-see-4kuhd-on-a-normal-sized-screen-you-betcha/ https://www.homecinemaguru.com/can-we-see-4kuhd-on-a-normal-... (The real limit seems only to start around 310 pixels/degree !)

iso1631 6y ago
That would suggest with the naked eye you could look at the moon and pick out features about 20km wide https://skyandtelescope.org/observing/how-to-see-lunar-craters-with-the-naked-eye102820152810/ https://skyandtelescope.org/observing/how-to-see-lunar-crate... "At 0.8′ (arcminutes) across, the crater alone hovers at the naked-eye limit" Which seems to back the the c. 1/60th idea. Judging the resolution of an eye is a subjective process, not least beacuse of the relative sensititivty and density of rods and cones at different parts of the eye.
- BlueTemplar 6y ago
  Exactly, 'subjective', the criteria the NHK used is 'sense of realness', not 'being able to consciously pick out features'.

trabant00 6y ago

Glad to see this get some exposure. It always kills me when people buy expensive 4k, curved, HDR, etc 50" TVs and sit over 10 feet away from them. (127 cm diagonal and over 3m away for Europe) You just threw your money away. Another thing is when you plan your sofa and TV furniture. Having over 10ft/3m (a common occurrence in homes) means you will need 100 inch screen for a cinematic experience, which means having lots of money or a projector, which brings a lot of problems itself. My personal setup is 6.5feet/2.5m 65 inch diagonal 1080p plasma Panasonic Viera from 2007. Everybody who hears about this thinks it's way too big for that close. But when guests ask for the specs of what they find an impressive picture in person they are always shocked to find it's "obsolete" technology. EDIT: as people dispute the real distance you can notice 4k vs 1080p, you don't need to trust any graph. Get close enough to your TV to notice individual pixels, then back away a little bit until you can't. That's the distance and I bet you will find it a lot close than you would think.

HPsquared 6y ago
It's a compromise between spacious living quarters (Feng Shui), and a cinematic experience when watching the TV.
- iso1631 6y ago
  Cinema means you want 30-40 degrees, but once you've fixed your screen size and your distance, you can then work out if 4k is worthwhile over 2k (or 8k over 4k) Of course this all falls down because it them comes down to availability, other features (number of hdmi ports, "smart" options, power use), and "4k" tends to also mean things like HDR, which is worthwhile (with the right source) no matter the screen.
- driverdan 6y ago
  > It's a compromise between spacious living quarters (Feng Shui) Feng Shui is not "spacious living quarters", it's pseudoscience nonsense.
BlueTemplar 6y ago
I wish I could buy a FullHD HDR TV...

mankyd 6y ago

Recently upgraded from a 1080p 40" TV to a 4k 55". According to this, at ~12ft away, we should have bought an 85" TV?! That's crazy and dumb. Or rather, a misrepesentation. This article states that we _could_ get away with up to an 85" TV. It is only at that limit that we'd start to see "imperfections" as they call it. I don't want to see imperfections. I also don't need a TV that will take up my whole field of view while bathing me in light. The 55" we have already feels quite large, much sharper, and is brighter. This article may be interesting from an academic point, but people shouldn't misconstrue this to think they should be getting a bigger TV. Get a TV that fits your space and feels comfortable. Bigger is not always equal to better.

hundchenkatze 6y ago
I think it's useful outside of an academic thought experiment. It hasn't encouraged me to get a bigger tv, quite the opposite. My takeaway isn't that I need a bigger tv, it's that I can get by with a smaller screen and lower resolution.
- mankyd 6y ago
  Except that at the very top is a slider that gives you a recommendation of screen distance to screen size. I think a lot of folks will encounter this and stop there.
  - hundchenkatze 6y ago
    Maybe, but the article is still useful for people that read it in it's entirety.
simlevesque 6y ago
You missed the point.
- mankyd 6y ago
  What is the point then? I feel as though lots of people will read this and say "My couch is 10+ feet from my tv. This states that I _need_ to get a giant tv".

jb1991 6y ago

I totally don’t understand what this chart is trying to expose. What is meant by the distance here?

iso1631 6y ago
Distance from eyeball to screen. There are 2 things this page shows, one is the size of screen you need relative on the distance you sit from it based on how much of your view you want it to fill, the other is what resolution the screen needs to be before you have no improvement. First decide what you want 30 degrees means you'll be able to focus on the picture, but it will fill your focus area, that's recomended by SMTPE 40 degrees is the "immersive" portfolio recommended by THX, you may lose some detail at the edge of the screen depending where you're looking. Then it's just a bit of trig to work out the size you need for the distance you are sitting (or vice versa), to match your preferred "fullness" Second is whether you'll benefit from more pixels. They base this on having 20/20 vision and your optical resolution being 1 arc-minute (1/60th of a degree). For comparison the moon is about 30 arc minutues wide. Seems reasonable to me, if I take a picture of the moon and shrink it to 30px by 30px, I feel it's on par with what I can see in real life. Then it's just more trig to work out how many pixels you need for a given size/distance combination. A 20" screen that's 10 feet away, you won't be able to tell the difference between SD and HD. A 40 inch monitor 2 feet away and you'll benefit from going higher than 4k. (This assumes a 16:9 aspect ratio).
- BlueTemplar 6y ago
  Except they are probably wrong... https://news.ycombinator.com/item?id=26088890 https://news.ycombinator.com/item?id=26088890
  - iso1631 6y ago
    Well they're quoting a definition of "20/20" vision from a researched article on wikipedia https://en.wikipedia.org/wiki/Visual_acuity https://en.wikipedia.org/wiki/Visual_acuity Which states "At 6 metres or 20 feet, a human eye with that performance is able to separate contours that are approximately 1.75 mm apart" Which I assume comes out at 1/60th of a degree. You could argue that measurement is in fact wrong, or that there's something happening subconciously, but their point is that based on accepted viewpoints that someone with 20/20 can't determine the difference between two contours 1mm apart from 6 metres, you don't need to display them. NHK by the way put a lot of money into developing 8k technologies, I saw it about 10 years ago. I was more impressed with the 120fps stuff than the higher resolution. YMMV.

apercu 6y ago

According to this I'm doing it wrong. And I don't care.

Navarr 6y ago

Would be nice if it threw in a "how far up the wall should this be" number

kec 6y ago
There’s no formula to spit out a handy chart for that. Center of the screen should be eye level for an adult sitting on your couch, ballpark 3’/1m for most setups.
sul_tasto 6y ago
just not too high... https://www.reddit.com/r/TVTooHigh/ https://www.reddit.com/r/TVTooHigh/

BuildTheRobots 6y ago

Quick point of note regarding TV resolution requirements: I've got an old Samsung 45" screen that's only 1080p. Usually films and other media look great on it and I was pretty convinced I didn't need a higher resolution. Last night I tried playing back some filmed-in 4k drone footage which ended up looking impressively awful. It was sharp, but lots of pixel level brightness noise changing from frame to frame, which looked grainy and was extremely distracting. I can only assume it's the way VLC or my graphics card are downsampling to display it at 1080, but it was annoying enough I'm now thinking of a new 4k TV at some point in the future. TLDR: Your source media might make a big difference.

SloopJon 6y ago

As for wasting your money on a 4K set vs. a full HD set, it almost isn't even a choice anymore. The "budget" 4K recommendation at RTINGS is about $500. Also, although it is mentioned in the text, keep in mind that not all content is high-bitrate 4K: Cable TV? Probably compressed 1080p or 720p, depending on the channel. If it's Comcast/Xfinity, they may even squeeze three channels into the bandwidth of two. Streaming? Compressed 1080p, with the occasional 4K. Old (but not that old) Blu-rays? 1080p. If you're sitting in your leather club chair, Oppo UHD Blu-ray remote in one hand and a glass of '92 Screaming Eagle Cabernet in the other, then sure--slide your chair into the sweet spot at the optimal distance per these charts. Don't get me wrong: when I replace my ten year-old Sony, it's going to be with the biggest LG CX or C1 OLED my wife lets me get. Just realize that trigonometry isn't the whole story.

cainxinth 6y ago
There’s still good, old fashioned antennas that deliver much less compressed video than cable.
- DavidPeiffer 6y ago
  About a week ago I heard about NextGen TV for the first time (ASTC 3.0). They're starting to roll out across the country will bring 4k content over the air. Not sure how compressed it will be, but I remember how revolutionary it was to switch to the digital OTA channels with a converter box many years ago. www.cnet.com/google-amp/news/watch-free-4k-tv-broadcasts-with-an-antenna-nextgen-tv-comes-to-more-cities-in-2021-atsc-3-0/

ksec 6y ago

Oh I am so glad this is on HN front page so I get to ask the question. Why 8K? I think people should try this at home. THX recommended Viewing Distance for cinema experience is 40 Degree. That is like sitting in the first few rows in a cinema that makes me sick watching movies. The maths that works for a 16:9 Display, 55" (inch) would be 5.5 Feet, 60" would be 6 Feet. Divide the display inches by 10 and change the unit to Feet. And assuming you are even somehow comfortable with this distance in everyday usage, you wont notice the pixel on a 4K TV with a 20/20 vision, what Apple calls it "Retina". For a 50" 4K TV it becomes "Retina" at a viewing distances of 39 inches. Some would argue 20/20 Visual Acuity is antique. With 20/15, Retina starts at 52 inches. That is still below the THX recommend viewing distance of 5.5 Feet, or 66" on 50" Display. What about the 20/10! Well that would be 78inch, so yes they could see those pixel. But that is only viewing at 40 degree angle. If you view it in what most would consider normal of 30 degree, you would be sitting at 6.8 feet or ~82inch away from the TV. I.e You still wont see those pixel. Also note we dont test moving object in visual acuity test. You are watching "Moving Pictures" on a TV. Not watching a single pixel. And if, in any case we need to optimise for the 5% with 20/10 vision that prefer to sit in the front row of the cinema. We could have went with 5K! And despite only 1K increase which seems very small, that is going from ~8M pixel to ~15M pixel. We would have room to spare even for the remaining 5% use case. And if we are so paranoid and need even more headroom. Even 6K will do. Instead we went for 8K; ~33M Pixels. The amount of bandwidth, computational power, compression, storage. We could have use those for higher frame rate when needed, 10bit colour accuracy by default or high quality colour profile. Instead we spent it on Pixel. And before someone jump in saying they could tell the difference between 4K and 8K. Remember the current marketing term of 8K Requires mandatory support of HDR and brightness level. Something 4K could do without. What you think of 8K being better may have nothing to do with pixel density at all. So apart from Sales and Marketing department pushing for it, ( along with Japanese government pushing it for Olympics ) like the days of Intel CPU pushing for Mhz. For someone who has no expert knowledge on the subject and merely an outsider, let me ask the question again. Why 8K?

StrictDabbler 6y ago
Moire effects. Modern TV sales demo videos are chosen for the exact kind of thing you start to see when the resolution gets higher. Footage of the ocean waves, schools of fish, flocks of birds. Moire effects and screengating are way larger than any one pixel. They make ripples and lumps in the image. You get used to the way hair looks on any generation of TV but it's nothing like "imperceptible" distortion. You can stand dozens of feet from an 8K, a 4K, and a 1080 TV and tell the difference when the image is of many tiny objects moving across each other. Grass. Leaves. Sand. A tiled floor viewed from an angle. You know, rare stuff like that.

mercora 6y ago

when reading about these considerations i always wonder if it really matters at which point i could discern single pixels from one another. i think there is more to it when we are talking about what we can see in the image. maybe we wont be able to benefit in the way that we see less of the pixel raster but i feel like having more details will benefit image clarity non the less. even if it is impossible to effectively discern the pixels the combination of them might still affect what i can see....

willis936 6y ago

I recently tried to appropriately set the FOV of first person shooters to match the FOV that the screen actually took up. I found that most games would not let me set my FOV that low, even when I was 1-2 feet away from a 24” monitor. It seems strange that it is given that people want a wider FOV than is natural. It gives a competitive advantage in the majority of scenarios, but I’m surprised more people don’t stop and think “this looks off”.

aidenn0 6y ago
The wider FOV makes me nauseous. Setting the FOV as narrow as possible lets me play FPS games. It took me a while to figure out why some games made me sick and others didn't. Turned out to be FOV.
- spathi_fwiffo 6y ago
  Interesting. I think I have the opposite issue. I try to get FOV in to 85 - 110 range. Otherwise i feel sick (or i need to sit far back from the monitor, which i can't really do on PC).
rozab 6y ago
Why would you want to simulate the experience of looking through a small window from a few feet away?
- willis936 6y ago
  To use a gamer buzzword: immersion. I usually play on PC. When I play games on my sofa (very narrow real life FOV) the issue is so pronounced that I feel like I’m on a treadmill. It pulls me out of the experience so much that I’d rather just play a different type of game.
hammock 6y ago
VR goggles. Turn 1-2 feet away into 1-2 inches away

zokier 6y ago

> The chart also shows that a 4k upgrade is not worth it if you are sitting more than 6' away and have a 50" TV. Your eyes won't be able to tell the difference. Doesn't the chart say exact opposite, the threshold for 50" 1080p is 6.3', so if your view distance is less than that (like 6.0') then 4k is worth it?

wing-_-nuts 6y ago

This has been on my mind a lot with the whole '4k gaming' push from the most recent consoles. 4k gaming just doesn't make sense for a lot of people. I have a 55" tv and sit 8.5' away from it. This TV is huge and dominates the room. I cannot reasonably have a larger tv or sit closer without ruining the usability of my livingroom. Most people simply sit too far away from to small of a TV to be able to tell 4k from 1080p. When people protest they can absolutely see a difference, what they're usually seeing is better color and contrast of newer tvs, not resolution. Even when it comes to PC gaming, 4k is often not all it's cracked up to be. According to OSHA, most people sit about 30" away from their monitor. This lines up nicely with the visual acuity distance for a 27" 1440p monitor. To reach the visual acuity limit for 4k, you'd have to sit 20" away. That's a lot closer than most people are comfortable with. Even a 32" model only expands it out to 25". That's within the realm of plausibility but another thing to keep in mind is viewing angles. The main theatre certification companies recommend anywhere from a 35-55 degree viewing angle. The visual acuity distance for 4k puts you at a whopping 60 degrees which is considered high for just consuming content, much less playing a game where you're expected to see everything happening on screen and react to it. TLDR: The hype of 4k for gaming is mostly just that. Most people would be far better served going for lower resolutions and higher refresh rates. The only people who really benefit from 4k are using it for productivity, coding, video editing, etc.

Dylan16807 6y ago
> a whopping 60 degrees which is considered high for just consuming content, much less playing a game where you're expected to see everything happening on screen and react to it. Consider that the game is probably rendering at least 90 degrees to squish down into that 60. Personally I sit back for content but I love to sit close for games, with the FOV set to max. The really important stuff fits in the middle of the screen, and outside of the middle I get near-peripheral vision instead of bezel and wall.
ants_a 6y ago
32" 4k monitor at a normal viewing distance (~30" seems like a good estimate without bringing out a measuring tape) is pretty comfortable for work at 100% scaling. At that distance 1080p video looks significantly worse when compared to 4k, although a large chunk of that may be due to bitrate.

aidenn0 6y ago

I got a mount that swings down from the wall. If you are going for a 40-degree view angle making the TV a foot closer is the same as making it 10" larger. It also has the advantage of going above furniture when not in use, but down at eye-level to the couch when in use.

PaulAJ 6y ago

Unfortunately this exhibits the usual confusion between pixel pitch and resolution, which makes it completely wrong. > Studies show that someone with 20/20 vision (or 6/6 in Europe) can distinguish something 1/60 of a degree apart. This means 60 pixels per degree [...] NOOOOO! "Resolution" is defined as the closest distance two dots can be while still appearing as two distinct dots. If you have two dots shown on adjacent pixels then you just see one big dot. You need the two dots separated by a pixel in order to see that there are two dots, so the resolution is half the pixel pitch. Worse yet, the two dots might be diagonal, so you need an extra factor of sqrt(2) in your resolution calculations. This means that the pixel pitch of a TV screen is 2 * 1.41 ~= 3 times its resolution. You need 180 pixels per degree if you have 20/20 vision, not 60. And it gets worse. Everyone knows that 20/20 vision is "normal". Well, not quite. 20/20 vision is the average without correction. Once you include glasses, 75% of people can actually see better than that, and some quite a lot better. So to be safe lets bump the pixel density up by another third, to 240 pixels per degree. That gives 7,200 pixels on a 30 degree screen.

dharmab 6y ago
Not to mention subpixel rendering and antialiasing, which can make a perceivable difference, e.g. text vs. video games.
elchief 6y ago
so how big a tv should I get?
nonninz 6y ago
So does this essentially mean that all those people who say things like "You don't need/can't distinguish 4K if your nose isn't touching the screen()" are wrong? I have always thought it was a strange thing to say. I can definitely see the difference between a 4K stream vs a 1080p one, even when the screen is much more far away than the recommended distance... () An hyperbole, obviously.
- timpattinson 6y ago
  To be fair the difference in bitrate between 1080/4k is probably (in my opinion) a bigger difference than the pixel count, uncompressed 1080 looks pretty damn good. but yeah the "the eye can't see >20fps" or a certain dpi is definitely BS.

elchief 6y ago

moves couch closer to tv... still waiting for ATSC 3.0, and the darn NFL and any Canadian broadcaster to show games in 4K

m-p-3 6y ago

I guess I need a 90" TV now.