Why Your HDTV Is Already A Retina Display

The term "retina display" is tossed around with increased frequency and decreased meaning. Is there really a strict definition anymore? Screen mega-expert Ray Soneira of DisplayMate points out that the biggest monitor in your house has been retina all along.

There is a widespread misunderstanding of exactly what constitutes an Apple "retina display" — or any display that has an equivalent visual sharpness. While the first retina display on the iPhone 4 has 326 pixels per inch (PPI), all retina displays don't need 326ppi because the eye's resolution is not based on linear pixels per inch but rather on angular resolution, so visual acuity depends on the viewing distance. That is why you take a standard vision test at 20 feet (6m) and aren't allowed to walk right up to the chart and read the smallest letters on the bottom line — visual acuity depends on the viewing distance.

Apple's retina display definition is equivalent to standard 20/20 vision — your eyes won't be able to resolve the individual pixels on the display provided you don't look at the screen from too close a viewing distance. If you have 20/20 vision and view the iPhone 4 from 10.5 inches or more, its display will appear "perfectly" sharp to your eyes — meaning the display appears at the visual acuity limit of your eyes. If the display were any sharper with a higher PPI or higher pixel resolution your eyes wouldn't be able to see the difference. That is what "retina display" means. Let's see what pixel density is needed for other displays in order to qualify as a Retina Display:

iPhone 4, new iPad 3 and MacBook Pro retina displays

The new iPad 3 and MacBook Pro have much lower pixel density than the iPhone 4, but Apple correctly markets them as retina displays because they are typically held further away from the eyes and therefore still appear "perfectly" sharp at their proper viewing distance. Below we have calculated the viewing distances needed to qualify as a 20/20 vision retina display (defined as one arc-minute visual acuity).

The iPhone 4 with 326ppi is a retina display when viewed from 10.5 inches or more The new iPad 3 with 264ppi is a retina display when viewed from 13.0 inches or more The MacBook Pro with 220ppi is a retina display when viewed from 15.6 inches or more

1920x1080 HDTVs

On the other hand, the average viewing distance for living room HDTVs is around two to three metres, depending on the screen size. So to appear "perfectly" sharp with 20/20 vision like the iPhone 4 retina display, HDTVs only need a proportionally much lower pixel density in order to achieve "retina display" status and have the HDTV appear "perfectly" sharp and at the visual acuity limit of your eyes.

Existing 40-inch 1920x1080 HDTV is a "retina display" when viewed from 1.5 metres or more Existing 50-inch 1920x1080 HDTV is a "retina display" when viewed from two metres or more Existing 60-inch 1920x1080 HDTV is a "retina display" when viewed from 2.4 metres or more

Since the typical HDTV viewing distances are larger than the minimum distances listed above, the HDTVs appear "perfectly" sharp and at the visual acuity limit of your eyes. At the viewing distances listed above the pixels on a 1920x1080 HDTV will not be visible by a person with 20/20 vision in exactly the same way as the retina displays on the iPhone 4, new iPad 3 and MacBook Pro at their viewing distances. So existing 1920x1080 HDTVs are "retina display" in exactly the same way as the existing Apple retina display products. If the HDTVs had a higher pixel density or a higher pixel resolution your eyes wouldn't be able to see the difference at their proper viewing distances. So existing 1920x1080 HDTVs are already equivalent to what Apple calls a "retina display". When Apple launches its own Apple television, it will almost certainly have a resolution of 1920x1080 and it will be a True Retina Display (for humans with 20/20 vision at standard HDTV viewing distances).

4K HDTVs and Projectors

Some manufacturers are introducing HDTVs with resolutions that are at least double the existing standard 1920x1080 resolution — 3840x2160 or more. They are often called 4K displays. Some reviewers have already claimed dramatically improved picture quality and sharpness, but that is impossible unless they have significantly better than 20/20 vision or are watching from an absurdly close viewing distance. However, the higher resolutions are important for digital cinematography and cinema projectors that have large 3m screens. But note that there isn't any consumer content available yet for resolutions higher than 1920x1080, so save your money and wait for the Apple television with a true 1920x1080 retina display.


Comments

    "and wait for the Apple television with a TRUE 1920×1080 retina display"
    Are you trying to have a lend of me - like what are we waiting for, and more expensive version of a TV?

      I really hope English is your second language

        I should hope it's yours too, punctuation obviously escapes you sir. If you wish to critique, ensure everything about yours is perfect first.

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                Mac and weresmurf should take heed of Muphry's Law:
                "If you write anything criticising editing or proofreading, there will be a fault of some kind in what you have written."
                Now that I have joined the fray, there is probably some glaring grammatical fault in this message that I am powerless to avoid including.

        They see me trollin'
        They hatin'...

        This comment has been deemed inappropriate and has been deleted.

          So my tv already has a retina display. Instead of buying a new one with higther resolution, I should wait for apple to release one with a "true" retina display? I think i have stumbled into the twilight zone (as in this website is as offensive as Twilight)

      I think he was having a dig at Apple, taking existing technology , slapping a buzzword onto the end and calling it magic.

        +1. That's exaclty what it is. Normal consumers don't know anything about resolutions, so throw some wanky term in there like "Retina Display", and you got yourself a sale!

          Indeed, it's a wanky term that in the end means absolutely nothing. I bought an iPad 3 the other day, it's quite lovely but I'll be damned if 'Retina display' had a single thing to do with it?

    "The iPhone 4 with 326ppi is a retina display when viewed from 10.5 inches or more"
    Do your writers have any basic knowledge of the topics they discuss? ppi doesn't change depending on how they are viewed, x pixels per inch. Seriously you guys are a joke.

      Did you read it properly. 326ppi is ONLY retina IF viewed from 10.5 inches or more. That's why even the 220 ppi Mac Book is considered retina when viewed at 15 inches or more.

      does CoreyE have basic knowledge of the english language? Apparently english comprehension does change depending on the persons view of Apple.

      sorry couldnt help myself. just lol.

    This is crap. Pixels are square. That means anything other than straight lines will be noticeably sharper at higher resolutions.
    If I'm watching my 50" screen at 1080p from 4 meters away, I can't see individual pixels, but large text (on ads) is fuzzy around edges. Just like the text on a 3GS is fuzzy compared to a 4S.

    I get your argument about the term "retina display" and what it means, but the rest of the article is complete crap.

      You're wrong here because your methodology is faulty: Pixels are square, yes, but the content in the ads is not likely to be broadcasting at full HD resolution.
      Many ads are in SD res or worse, often containing horribly compressed elements and shocking graphic design.
      If you want to do a real test of large text on your HD screen then view some text in vector art on it (plug it into your computer?). You can blow it up to any size and it'll appear sharp, crisp and clean from even a pretty close viewing distance.

        I have to agree completely with Tristan's comments. The resolution of the eye is not perfectly mappable to the resolution of a screen. For one the retina is not arranged in a grid - the dpi/ppi that is referred to as the resolution of a retina is an approximation of an organic matrix which is more hexagon like.

        Whenever a pixel in a display does not map directly onto an equivalent sensor "unit" within the eye - when a pixel on the screen is being perceived by more than one sensor in the retina - there will be some loss of fidelity. And even if the retina WAS arranged in a grid pattern this misalignment would be the norm - the majority of all perception would be of the misaligned case.

        Just because the eye cannot consciously perceive an individual pixel does not mean that the size of the pixels is no longer relevant - finer resolution can still add greatly to the perception of sharpness by reducing the number of pixels which are being blurred by the process of being perceived by more than one retina sensor.

          Interesting stuff. But I think what it comes down to is the validity of the claim - "further pixel density can't be distinguished by the human eye". Even if your science is right, I assume they've done a test and people can't distinguish the difference.

            except they can tell the difference, and the article is wrong about 4K not looking better than 1080P, I'm sure there have been articles on gizmodo itself about how they look better.

            And I remember stories from a few years ago about universities in Japan showing of certain ultra high def and people actually felt sick because it looked "too real".

            http://www.wired.com/science/discoveries/news/2005/09/69039 <--An example.

            Look at people talking about The Hobbit in 4K and people criticize the look of it, it clearly is noticeably different to 1080P.

              People were criticizing The Hobbit because of the frame rate (48fps vs Normal 24fps), not the resolution.

            I remember everyone claiming that the human eye couldn't tell the difference between 710p and 1080p in a normal lounge room situation when we went from HD to Full HD standard.

            They were wrong too.

          The arrangement of pixels in a grid or hex pattern is irrelevant to the clarity of text at the correct distance: it all blends into one mass regardless. Try sitting at the correct distance and viewing victor text on an HD screen. It won't "fuzzy" as Tristan imagines.

      Are you trolling?

      Could it be fuzzy because the content isn't 1080p (ie: most ads).

      And the 3GS is far from Retina as well, that's why things look fuzzy...I guess it could be retina if you looked at it from (est.) 20" away (correct me if I'm wrong)

      You must be joking - you're not actually that dim, surely? Text doesn't come in one resolution... Hate to break it to you but your comment is the only thing that is complete crap.

      Have you tried watching a full 1080p movie on your screen from 4 metres away?

    The article is exactly right. Good to see something this sharp amidst the childish babbling that normally surrounds the "retina" buzz-word.

    Marketing BS.

    Yes more pixels is better but unless the media is right well more pixels are wasted.

      For people to buy high resolution media, they first must have a high resolution display. When iPhone 4 came out, hardly any apps supported the resolution. Now all of them do.

      What I really want to see is a movie mastered for 4K, then sold through iTunes for these super high resolution displays Apple is making. It would be a shame to put such super high resolution displays on iPad, MacBook and iTV (?) and not release any movies mastered for these resolutions. Another problem is that in some countries, especially America and Canada, the cable monopolies have no interest in upgrading their infrastructure in order to routinely deliver a 15GB 1800p movie file :(

      Australia will be primed for it, with the NBN in a few years. What a bizarre world, where Australia outclasses America in terms of this kind of technology.

    Fantastic article. I had deduced this myself while buying my new 50" TV but had never been certain I was correct.

    Now would love to see a similar article on the Sharp Quattron bullsh!t... Yellow pixels, what a joke. Purple, brown and orange pixels next? What about a pixel for every colour?...

      http://dl.maximumpc.com/Archives/MPC0710-web.pdf

      Page 45-51. Specifically page 51. Good read, actually.

        Great read. Highly recommend this article. Surely it's time to put a stop to the ridiculous tech spec claims! A governing body to test displays against their specs???

    Isn't the whole "retina" tag line to applied screens more to do with the technology they had to invent IN ORDER to squish that many pixels into such a small screen, rather than the actual number of pixels over all? Something about creating a whole new system where the pixels themselves are separated from the signals that activate them?

      No, that's just the marketing BS, pure and simple. There's no real leap to get to "retina", just the usual incremental, linear development progress. It's about clarity of resolution.

    Full HD is enough for anyone!

      Facetious?
      The hard facts are that depending on the size and the screen and the distance you are from it, there is only so much resolution that you will ever be able to see.

      If the TVs get larger or you project at a really high size, and if you sit really close to a big screen then you will need a higher res than "HD" to maintain the same clarity. But at ordinary viewing distances, 40-60 inch HD TVs are as clear as you eyes can make out. Is that logic and science so hard?

        You sound like one of the people that would of been making the same claims for 720p screens only a few years ago.

          You sound like a person that doesn't understand explanations. 720p will appear totally clear on a very small screen with enough viewing distance, it's the same argument and extremely obvious science. Larger resolutions look better at larger sizes. Why do you have trouble with this?
          It seems that some people approach this subject with an attitude akin to religious faith rather than logic.

            Surely he was referring to Dean and just hit the wrong reply button?

    4k makes compression and filming artefacts smaller, you can't see more pixels, but you can definitely see a considerable difference in quality.

      That's due to the recording and compression techniques, not anything to do with the display it's being shown on. Yes, a 4K recording has smaller compression and filming artefacts, but they'd be just as small on a 1080p display too. The larger the file resolution, and less compression, the better the quality, on any display.

    Is it really worth all the debate? If you don't want more pixels, shut up and be happy with what you've got while the rest of us push toward resolutions so tight that when watching a nature documentary you'll be able to see when a bee has an erection. You'll see that because the picture will look so damn good, you'll want to get off the sofa and take a closer look!

    Sometimes I like to sit on the floor in front of the big screen TV when playing a new game or watching a good Blu Ray. It really doesn't look very good when you sit up close (not to mention that most PS3 and 360 games look like arse anyway).

    It's better to have a higher resolution than to not have it, I think it will be great when all displays are very high resolution and all media is also very high resolution. How could would it be to zoom in and remove the black bars from one of those really wide screen movies, and still have perfect quality. It would be great. And it doesn't make sense to me to just stop at 1080p displays and say "it's good enough for most viewing distances, let's just keep on devoting human endeavour to 1080p". No, we should be using our human endeavour with R&D and manufacturing techniques to always be improving what we have :3

    Fortunately, people vote with their wallets. Apple are going to keep making very high resolution displays, and people will want them, which will drive the rest of the market to move to very high resolution sooner than they might have.

      1. Zooming in and removing black bars and retaining quality has nothing to do with screen res, that's about the res of the video, so this does not apply to your argument.
      2. As the article explains, Apples screens are functionally the same res as HD TVs because they are tiny and you sit close to them ;)
      If you want higher res big screens, Apple isn't making them, I think the biggest they make are 30 inch displays, and even though the res is high, it's definitely not 320 DPI or whatever. If you want big screens at higher res they're already available from other people.

    I hope my current TV lasts long enough to either upgrade to an OLED big screen or 4K TV.

    I can't remember if it was Engadget or Gizmodo, but I remember reading an article on one about seeing an 8k TV, and how it was the single most emersive thing they've ever seen, as clear as looking out a window.

    For them to even be able to notice how much better 8k is at a normal viewing distance shows that Full HD isn't as good as you can get, and things will keep getting smoother for the next 15-20 years.

    retina display = bullshit marketing term not actual technology. what comes next? optic nerve display? what is wrong with people, have they let marketing rule their minds completely now, or is it just the writers of this website

      Thank the lord. Someone else agrees. I have to say, for those of you convinced that content for these ultra high resolution displays will become available any time soon - you're smoking rocks. Do any of you understand the changes required for production companies and facilities to ramp up to support this? NO. Otherwise, you wouldn't blab on and on about how you can't wait for your next OLED display or 4k TV. Give me a break!

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