A 4K 27-inch iMac is not a Retina iMac

[Serban]

A geforce 850M up to 880M will be enough for a 4K iMac, like Apple put a HD4000+650M for retina macbook pro.

So the display it's already good enough on the current displays, they only need the ppi to be increased over 160 ppi

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And everybody said that Yosemite is build for retina..so this year at least one of those (retina imac OR retina thunderbolt display) will be shown in October and the price should not be raise more than 300-500$ from the current lineup

 

[AxoNeuron]

So we've been using the term "4K iMac" and "Retina iMac" interchangeably, but in reality they are different things. A 4K iMac at 3840x2160 is an improvement over 2560x1440 but the pixel density would only go from 109ppi to 163ppi. That's a nice to have, but it's not the life changing visual experience the Retina MacBook Pros or iOS devices had after being truly pixel-doubled to Retina.

Plus, a 4K 27-inch iMac would be nearly unusable at native resolution so you'd end up running it at "Best for Retina" which would simply be 1920x1080 HiDPI mode...essentially cutting the perceivable screen real estate vs what we have now. You could then scale the display for more space but you'd lose some of the crispness you bought it for. We're still very far off from 5120x2880 which would be a truly Retina version of the current 27-inch iMac so anyone holding out on buying a 27-inch in hopes for a Retina version may want to reconsider.

It all depends on the viewing distance, not the PPI in and of itself.

Using a "retina" calculator, if you sit 50cm away from a 27" iMac with a 4K resolution, that actually would be "Retina". It's the same reason that the iPad air doesn't need the same 326 PPI resolution density of the iPhone 4+, because users tend to use the iPad at a greater distance than the iPhone. And it's the same reason that a 1080P TV is considered "retina" at a great enough distance.

The average viewing distance of the 27" iMac for most people is about 50cm, so a 4K iMac definitely would be a "retina" experience. Also, you say that you would have to run the display at a scaled HiDP resolution. This is correct. But it wouldn't need to be 1080p at all. You could easily run it at a scaled 2560x1440 HiDP mode, the scaling factor just wouldn't be a whole-number (which isn't necessary).

 

[Serban]

My friend has a 4K 29" monitor and it is retina...even from close distance the image is clear...so

 

[joe-h2o]

I think truly retina means a very crisp, clear screen... and that an inability to distinguish individual pixels is just part of that.

Another important part of that, as OP points out, is the the pixel doubling.

So, while you don't need 5120x2880 @ 27" for the sake of pixel size (for most of us), you do need it to double the pixels without losing screen real estate vs. the current iMac.

Personally, I think the 27" iMac has an overabundance of screen real estate, so I'd be willing to give up some... but not to the degree of 1920x1080 (which pixel doubles to 3840 x 2160). Also, I suspect that's not quite retina even by the pixel distinguishing rule for most of us... just a guess though... maybe 4K at ~23" would do it?

Anyway, you're all welcome to define retina any way you want, but if the display quality isn't there, then what's the point?

I'm not defining retina "any way I want", I'm using Apple's mathematical formula, so I'm defining retina the way Apple does.

If you cannot distinguish individual pixels then the screen will be sharp and well defined - that's the point of resolving detail by your eyes. Either the screen is or isn't.

 

[PatriotInvasion]

Wrong.

A 4k panel at 27" on an iMac would definitely be retina.

The current 2560x1440 resolution is almost retina at the optimal viewing distance from the screen - it's 80% to 90% of the way to being retina as it is. Going to 4k resolution would be more than adequate - at a 21" viewing distance a 27" 4k panel is a retina screen.

You don't need 5120x2880 for "truly" retina, since retina simply means "the inability to distinguish individual pixels" - for a 4k 27" panel this distance occurs at 21 inches - well inside the viewing distance for a 27" panel, so a 4k 27" screen is already "truly retina".

Fine. We can debate Retina vs non-Retina based on viewing distance all we want (btw I sit 2 feet from my iMac usually, but if I pull my chair in, my eyes may be 19 or 20" away...now it's not a Retina display, lol). Doesn't change my other point in that Apple must lower the real estate of what 27" iMac users have been used to for 5 years now in order to accomplish a 4K/Retina iMac. For people who would find 1920x1080 UI comically large on a 27" display this is a bit of a buzzkill. Hopefully the added pixel density makes up for it when it comes out.

 

[AxoNeuron]

Fine. We can debate Retina vs non-Retina based on viewing distance all we want (btw I sit 2 feet from my iMac usually, but if I pull my chair in, my eyes may be 19 or 20" away...now it's not a Retina display, lol). Doesn't change my other point in that Apple must lower the real estate of what 27" iMac users have been used to for 5 years now in order to accomplish a 4K/Retina iMac. For people who would find 1920x1080 UI comically large on a 27" display this is a bit of a buzzkill. Hopefully the added pixel density makes up for it when it comes out.

2 feet = 50cm = retina. If you did get closer, it would no longer meet the technical definition of a retina display density. However, most people sit about 50 cm away or father from the 27" display. So it would be retina. It's the same with the 326PPI resolution on the iPhone, if you're 10" away it is retina, but any closer and it is no longer technically retina.

Also, you keep saying Apple would have to scale it to 1920x1080 HiDP. This is incorrect. Apple could easily scale it to 2560x1440 HiDP, they would have to use a non-whole number scaling factor but it's still very easily doable. They could render applications at 5120x2880 resolution and then use software to minimize them to a 1440p scaling factor, which is already a common practice to get applications rendered correctly on HiDP displays.

 

[PatriotInvasion]

Also, you keep saying Apple would have to scale it to 1920x1080 HiDP. This is incorrect. Apple could easily scale it to 2560x1440 HiDP, they would have to use a non-whole number scaling factor but it's still very easily doable. They could render applications at 5120x2880 resolution and then use software to minimize them to a 1440p scaling factor, which is already a common practice to get applications rendered correctly on HiDP displays.

They can do this and it will be an option but it won't be the "Best for Retina" default in Display settings. You will also lose a bit of crispness because it's not a perfect 2x transition based on a 3840x2160 4K display resolution. So yes, a 4K iMac can be scaled to 2560x1440 if you prefer to have that much real estate again, but it won't look as good as 1920x1080 in HiDPI mode on a 4K display.

My whole point is that for Apple to achieve Retina on a 27" iMac it will have to be done in a slightly different way than every other Retina display they've released thus far simply because technology doesn't support 5120x2880 right now. It'll be an awesome machine when it comes out regardless (especially Rev B when the internals catch up to the resolution).

 

[joe-h2o]

Fine. We can debate Retina vs non-Retina based on viewing distance all we want (btw I sit 2 feet from my iMac usually, but if I pull my chair in, my eyes may be 19 or 20" away...now it's not a Retina display, lol). Doesn't change my other point in that Apple must lower the real estate of what 27" iMac users have been used to for 5 years now in order to accomplish a 4K/Retina iMac. For people who would find 1920x1080 UI comically large on a 27" display this is a bit of a buzzkill. Hopefully the added pixel density makes up for it when it comes out.

You just contradicted yourself. Two feet is 24 inches, which is outside the minimum viewing range for a 4k display to be retina - it becomes retina at 21" view distance.

The current iMacs (27" panel ones) are retina beyond 32" or so, which is a little further away than most people view, but Apple does not market them as retina displays for this reason.

There's no need to do any pixel doubling, or to display at an effective 1080p resolution. There are several high dpi techniques that will ensure that a theoretical 4k 27" panel in an iMac will look very crisp and sharp and still retain the large screen real estate.

 

[PatriotInvasion]

You just contradicted yourself. Two feet is 24 inches, which is outside the minimum viewing range for a 4k display to be retina - it becomes retina at 21" view distance.

I didn't, I was simply pointing out the humor in this 21" distance being the 4K Retina threshold that I sometimes cross depending on how far my chair is pulled in to my desk. I have long since conceded the Retina definition by distance in subsequent posts after my first.

There's no need to do any pixel doubling, or to display at an effective 1080p resolution. There are several high dpi techniques that will ensure that a theoretical 4k 27" panel in an iMac will look very crisp and sharp and still retain the large screen real estate.

This isn't right if Apple wants to replicate what it has done on the Retina MacBook Pros. Using the 15" as an example - it's 2880x1800 native display comes set at a screen real estate of 1440x900 perfectly pixel doubled into it's native resolution. While you have the option to scale this up as high as "Looks like 1920x1200", you are sacrificing crispness (since those scaled resolutions don't perfectly equate to native in HiDPI) and graphics performance (due to the off-screen rendering that has to happen). So yes, you can run a 4K iMac at a scaled 2560x1440 resolution but it will not look as good as 1920x1080 HiDPI. That's a fact.

 

[Serban]

Phil: "Today we release a retina 27" iMAC starting from 2099$ "

 

[PatriotInvasion]

Phil: "Today we release a retina 27" iMAC starting from 2099$ "

Hope they find a way to make that starting number $1,999 or else there will be massive sticker shock. Based on the cost of high end standalone 4K displays right now, I don't see how they get to that number but we'll see.

 

[Moonjumper]

There's no need to do any pixel doubling, or to display at an effective 1080p resolution. There are several high dpi techniques that will ensure that a theoretical 4k 27" panel in an iMac will look very crisp and sharp and still retain the large screen real estate.

But no method that Apple has done before. They have always pixel doubled. I'm not saying they won't, but it doesn't seem like a compromise Apple would make.

I have a thought on another possible route, but I freely admit this is only a guess. Apple have successively increased screen size. We might get a 24" retina iMac with a 4K screen as the new small size, with a larger 30" retina iMac in the future when technology catches up.

 

[Serban]

Hope they find a way to make that starting number $1,999 or else there will be massive sticker shock. Based on the cost of high end standalone 4K displays right now, I don't see how they get to that number but we'll see.

Remember the price with Mac Pro and those D500 D700....so they can do it, but i still think they will be starting from 2099 and the high end from 2299$

 

[AxoNeuron]

They can do this and it will be an option but it won't be the "Best for Retina" default in Display settings. You will also lose a bit of crispness because it's not a perfect 2x transition based on a 3840x2160 4K display resolution. So yes, a 4K iMac can be scaled to 2560x1440 if you prefer to have that much real estate again, but it won't look as good as 1920x1080 in HiDPI mode on a 4K display.

My whole point is that for Apple to achieve Retina on a 27" iMac it will have to be done in a slightly different way than every other Retina display they've released thus far simply because technology doesn't support 5120x2880 right now. It'll be an awesome machine when it comes out regardless (especially Rev B when the internals catch up to the resolution).

There is one fact that completely disproves your entire argument. As we all know now, at 50cm (20in) a 4K panel on a 27" iMac would meet the criteria for a "retina" display, and this is the typical distance for users of the 27" iMac.

Apple wouldn't have to pixel-double at all. Apple would not have to scale it to 1080 HiDP either. You say that "it would not be as crisp" since they couldn't use a whole-integer scaling factor, but this is also untrue. The truth is, Apple already DOES this on the Retina MacBook Pro. On the Retina MacBook Pro, it comes with several scaling options for HiDP (1024 x 640, 1280 x 800, 1440 x 900, 1680 x 1050 and 1920 x 1200 SOURCE). Only one of these (1440x900 HiDP) is a whole-integer scaling factor, and the other scaling resolutions still look just fine. They don't have a problem with crispness at all. These are the relative scaling factors, in order: 2.81x, 2.25x, 2x, 1.71x, 1.5x.

Thus, Apple has proven already that you don't need to use a whole-integer scaling factor. So it would be very simple for them to slap a 4K panel in to the 27" iMac and then scale everything to be 1440 HiDP, so that while everything stays the same relative SIZE as it was on the old iMac, it is much sharper. In fact, Windows does this already as well, albeit not nearly as well as OS X does.

So basically, the 27" iMac and a 4K panel are almost destined for one another, it's almost as if the 4K resolution was created specifically for the 27" iMac it works so well

 

[iSee]

I'm not defining retina "any way I want", I'm using Apple's mathematical formula, so I'm defining retina the way Apple does.

If you cannot distinguish individual pixels then the screen will be sharp and well defined - that's the point of resolving detail by your eyes. Either the screen is or isn't.

It's a marketing term. You're kidding yourself if you think it's defined my a mathematical formula.

Human visual perception and computer graphics are complicated. It's not so simple that if you can't distinguish individual pixels then the screen will be sharp. Books have been written on this.

What we (as users) want from a Retina display is a really sharp and clear display, not a certain pixel-size to viewing-distance ratio. The pixel-doubling scheme is an important part of that because it gives excellent results across a very wide range of source graphics.

I don't think you'd be too satisfied with a screen that was "Retina" according to pixel size and average viewing distance, but a lot of stuff you viewed was fuzzy.

 

[Dilster3k]

I too prefer going overboard with the resolution like how they did with the rMBP.

The resolution of the rMBP may not exceed 300ppi (true retina) but at the average distance from a laptop it's fine, also, it leaves enough room for tools with FCPx while simultaneously displaying full 1080p at the top right. It would be great if the iMac could do the same with 4K content.

 

[PatriotInvasion]

There is one fact that completely disproves your entire argument. As we all know now, at 50cm (20in) a 4K panel on a 27" iMac would meet the criteria for a "retina" display, and this is the typical distance for users of the 27" iMac.

Apple wouldn't have to pixel-double at all. Apple would not have to scale it to 1080 HiDP either. You say that "it would not be as crisp" since they couldn't use a whole-integer scaling factor, but this is also untrue. The truth is, Apple already DOES this on the Retina MacBook Pro. On the Retina MacBook Pro, it comes with several scaling options for HiDP (1024 x 640, 1280 x 800, 1440 x 900, 1680 x 1050 and 1920 x 1200 SOURCE). Only one of these (1440x900 HiDP) is a whole-integer scaling factor, and the other scaling resolutions still look just fine. They don't have a problem with crispness at all.

This is just incorrect. Perhaps you can't tell the difference between the crispness of your rMBP when using the scaled resolutions outside of the "Best for Retina" setting but most people do and it's a well known fact on tech blogs that these resolutions sacrifice a little bit of crispness in exchange for real estate. Even your own source link confirms this:

"By default, the Retina MBP ships in a pixel doubled configuration. You get the effective desktop resolution of the standard 15-inch MacBook Pro's 1440 x 900 panel, but with four physical pixels driving every single pixel represented on the screen. This configuration is the best looking..."

"Apple offers five scaled settings including the default pixel doubled option: 1024 x 640, 1280 x 800, 1440 x 900, 1680 x 1050 and 1920 x 1200. Selecting any of these options gives you the effective desktop resolution of the setting, but Apple actually renders the screen at a higher resolution and scales it to fit the 2880 x 1800 panel. As a result of the upscaled rendering, there can be a performance and quality impact."

 

[AxoNeuron]

This is just incorrect. Perhaps you can't tell the difference between the crispness of your rMBP when using the scaled resolutions outside of the "Best for Retina" setting but most people do and it's a well known fact on tech blogs that these resolutions sacrifice a little bit of crispness in exchange for real estate. Even your own source link confirms this:

"By default, the Retina MBP ships in a pixel doubled configuration. You get the effective desktop resolution of the standard 15-inch MacBook Pro's 1440 x 900 panel, but with four physical pixels driving every single pixel represented on the screen. This configuration is the best looking..."

"Apple offers five scaled settings including the default pixel doubled option: 1024 x 640, 1280 x 800, 1440 x 900, 1680 x 1050 and 1920 x 1200. Selecting any of these options gives you the effective desktop resolution of the setting, but Apple actually renders the screen at a higher resolution and scales it to fit the 2880 x 1800 panel. As a result of the upscaled rendering, there can be a performance and quality impact."

My own source didn't even mention the word "crispness", so how could he confirm that you sacrifice crispness for screen real-estate? t like how you chose where to end that quote. Here's the entire quote:

"By default, the Retina MBP ships in a pixel doubled configuration. You get the effective desktop resolution of the standard 15-inch MacBook Pro's 1440 x 900 panel, but with four physical pixels driving every single pixel represented on the screen. This configuration is the best looking, but you don't actually get any more desktop space. Thankfully Apple exposes a handful of predefined scaling options if you do want additional desktop space."

When he says it's "best looking", he's talking about SIZE, not crispness. He doesn't say anything about this "crispness" problem you're talking about, which just doesn't exist.

While I can see that you do not own a Retina macbook pro, I do, and I use it at a scaled resolution of 1050 HiDP, not the default 2x scaler. And there are NO problems with crispness, it looks every bit as sharp as the 2x scaler.

Also, the "performance and quality" impact he mentions is the fact that it still renders the image at a larger pixel density and then scales it down to whatever scale you choose. The fact that it has to divide the resolution by 1.71x as opposed to 2x doesn't produce any performance penalty on my system, and it's not widely noted elsewhere either. The performance "impact" is so tiny that he doesn't even bother to elaborate, because it isn't that much harder for a modern GPU to divide by 1.71x than by 2x, the impact is solely theoretical. I will perform benchmarks with both scaling options if you would like me to prove this point.

So, this "crispness" problem you mention being an issue with not using whole-integer scalers is not a problem at all, and the "performance impact" is unnoticeable. On a system as powerful as the iMac, with it's dedicated discrete GPU, this would be even less of an issue.

 

[TMRaven]

I think something like a Spline interpolation when working with that much resolution would still be pretty damn crisp.

But alas I can't sit here and compare a 27" screen natively running at 2560x1440 against a 27" screen running an upscaled and interpolated 2560x1440.

I think the most practical solution is apple takes the 21.5inch iMac and brings it up to 4k for 'retina' resolution, while it holds off on the 27 inch iMac.

 

[PatriotInvasion]

My own source didn't even mention the word "crispness", so how could he confirm that you sacrifice crispness for screen real-estate? t like how you chose where to end that quote. Here's the entire quote:

"By default, the Retina MBP ships in a pixel doubled configuration. You get the effective desktop resolution of the standard 15-inch MacBook Pro's 1440 x 900 panel, but with four physical pixels driving every single pixel represented on the screen. This configuration is the best looking, but you don't actually get any more desktop space. Thankfully Apple exposes a handful of predefined scaling options if you do want additional desktop space."

When he says it's "best looking", he's talking about SIZE, not crispness. He doesn't say anything about this "crispness" problem you're talking about, which just doesn't exist.

While I can see that you do not own a Retina macbook pro, I do, and I use it at a scaled resolution of 1050 HiDP, not the default 2x scaler. And there are NO problems with crispness, it looks every bit as sharp as the 2x scaler.

Also, the "performance and quality" impact he mentions is the fact that it still renders the image at a larger pixel density and then scales it down to whatever scale you choose. The fact that it has to divide the resolution by 1.71x as opposed to 2x doesn't produce any performance penalty on my system, and it's not widely noted elsewhere either. The performance "impact" is so tiny that he doesn't even bother to elaborate, because it isn't that much harder for a modern GPU to divide by 1.71x than by 2x, the impact is solely theoretical. I will perform benchmarks with both scaling options if you would like me to prove this point.

So, this "crispness" problem you mention being an issue with not using whole-integer scalers is not a problem at all, and the "performance impact" is unnoticeable. On a system as powerful as the iMac, with it's dedicated discrete GPU, this would be even less of an issue.

What you bolded above does nothing to help your argument. He doesn't say that configuration looks best simply based on desktop space. Here is Apple's OWN support article regarding this topic in which even APPLE states:

"Note: Scaled resolutions do not offer the same visual quality as the Retina setting. Scaled resolutions may also impact graphics performance depending on which applications you are using."

http://support.apple.com/kb/HT5266?viewlocale=en_US&locale=en_US

Argument over. Dropping the mic.

PS - I typed this on my work 15" rMBP. The iMac in my sig is my home Mac.

 

[AxoNeuron]

What you bolded above does nothing to help your argument. He doesn't say that configuration looks best simply based on desktop space. Here is Apple's OWN support article regarding this topic in which even APPLE states:

"Note: Scaled resolutions do not offer the same visual quality as the Retina setting. Scaled resolutions may also impact graphics performance depending on which applications you are using."

http://support.apple.com/kb/HT5266?viewlocale=en_US&locale=en_US

Argument over. Dropping the mic.

PS - I typed this on my work 15" rMBP. The iMac in my sig is my home Mac.

Why do you think Apple even offers the scaled resolutions if they have such a horrifying impact on performance and quality? The reason is, it only impacts performance + quality in very specific situations in (usually older) applications.

In that Kbase article, Apple is discussing larger scalers, not smaller ones. In most non-retina Applications, text will still look OK if scaled at a whole-integer value and made bigger, still pixelated but acceptable. But if you scale them with a floating-point value and then make them bigger, non-retina applications will look much more pixelated. This is what Apple is discussing, and a supremely obvious fact. When you take an Application that has only been written to support non-Retina displays, and then make it much bigger ON a retina display, it will look much worse.

But what you mentioned earlier was scaling to make items smaller, ie. not 1080p scaling on a 4K display. This has no visual quality impacts whatsoever, in fact applications that are not made for retina displays will look even better on a retina display when you use a SMALLER scaler, regardless of whether or not it's a whole-integer scaler. This is exactly what I am talking about with a 4K iMac. Apple would never scale a 4K 27" iMac to 1080p, they would scale it to 1440 HiDP. While SOME applications, as Apple mentions, are not built for retina and would have performance issues, this occurs even at 2x whole-integer scaling, and any retina display would have these issues regardless.

Regarding the performance impacts, Apple's kbase states in your own quote that these only occur in certain applications, usually video games, which do not support retina-level resolutions. This would happen regardless of the resolution/scaler you use. Some applications are not written to support retina resolutions, and the scaling would have no difference at all.

 

[PatriotInvasion]

Why do you think Apple even offers the scaled resolutions if they have such a horrifying impact on performance and quality? The reason is, it only impacts performance + quality in very specific situations in (usually older) applications.

I never said the scaled resolutions have a "horrifying" impact. Only was making the point that the visuals will not be quite as crisp which Apple confirms. Apple offers them because some people may want more real estate and are willing to take the visual quality (Apple's words) and occasional performance downgrades in exchange.

So circling back to my original point. If Apple is to release a 4K iMac, and call it Retina, they will almost certainly have it set at Best for Retina which will be pixel doubled 1920x1080. If you want 2560x1440, it will be scaled and "will not offer the same visual quality as the Retina setting." (again, Apple's words).

 

[AxoNeuron]

I never said the scaled resolutions have a "horrifying" impact. Only was making the point that the visuals will not be quite as crisp which Apple confirms. Apple offers them because some people may want more real estate and are willing to take the visual quality (Apple's words) and occasional performance downgrades in exchange.

So circling back to my original point. If Apple is to release a 4K iMac, and call it Retina, they will almost certainly have it set at Best for Retina which will be pixel doubled 1920x1080. If you want 2560x1440, it will be scaled and "will not offer the same visual quality as the Retina setting." (again, Apple's words).

These issues would only occur in older applications that are not written to support retina resolutions. And in fact, this problem still occurs even at 2x "Retina" scaling, it's just the least bad looking. But scaling it at slightly smaller sizes actually makes it look even better, which is what Apple would do, with 1440 HiDP scaling to match the current resolution. And in fact, for older applications that do not support retina displays, there is a "non retina" setting that would abolish the issue entirely, and OS X can scale just that app to 2x or whatever.

This just wouldn't be a large problem. Apple already dealt with all of these issues with the first retina macbook pro, and upscaling the 27" iMac to a higher 1440p resolution to make text/other items slightly smaller would actually lessen the problem. The only time users would actually start encountering performance issues would be if they tried to upscale to some games at resolutions lower than 1080 HiDP, which would cause the GPU to work harder than normal trying to render more texture detail than normal for a given 3D object. But it would hardly be a common issue.

It's all a problem with older software, and Apple has historically not let that keep it down.

 

[joe-h2o]

It's a marketing term. You're kidding yourself if you think it's defined my a mathematical formula.

Human visual perception and computer graphics are complicated. It's not so simple that if you can't distinguish individual pixels then the screen will be sharp. Books have been written on this.

What we (as users) want from a Retina display is a really sharp and clear display, not a certain pixel-size to viewing-distance ratio. The pixel-doubling scheme is an important part of that because it gives excellent results across a very wide range of source graphics.

I don't think you'd be too satisfied with a screen that was "Retina" according to pixel size and average viewing distance, but a lot of stuff you viewed was fuzzy.

http://i.imgur.com/r02s0.png

That's Phil Schiller by the way, just for clarification.

Sorry, you were saying something about not being based on a formula? Do carry on.

 

[PatriotInvasion]

Stalemate. Anyone else have an opinion to break the gridlock?