Newbie confused by retina iMac desktop resolution

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Background:
I've waited for there years for "retina" to make it to a big display, so that finally I can see my camera's photos 1:1, so I'm all eager to buy the new 27" retina iMac. Today, I had a look at one in a shop, but was underwhelmed, because the 5k desktop background photo (the usual mountain) didn't look significantly different to an old 27" iMac.

However, when I had a look in the display preferences, I found it was set to 2560x1440 as the "best for retina" display and there was no way to set it to 5120x2880. Ok, so I figure it's scaled so that windows and content doesn't look too small, but surely you can still see photos unscaled ...so I find a 5k photo on the iMac and open it in Preview(?) thinking I'll finally see a photo at 1:1, aka 100%, but when I do that, I get scrollbars and the photo is 2x as tall and 2x as wide as the screen, so it sticks to the desktop resolution and I'm only seeing 2560x1440 of the photo at a time, with each pixel of the image is occupying 4 pixels of the native display, right?

Question:
I don't get it, where's the point of 5K / how do I get to see a photo pixel for pixel at "100%"?
Everyone has their own reasons, but for me that's the main reason to buy my first computer in over 5 years (and it would be my first Mac) and if that's not possible, then I wouldn't buy it, but rather wait.

Thanks for any enlightenment and explanations!
Paul
 

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The retina display makes things look sharper (more pixels/inch…PPI). It does not give you more screen real estate.

- Nick
 

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However, when I had a look in the display preferences, I found it was set to 2560x1440 as the "best for retina" display and there was no way to set it to 5120x2880.

Are you kidding? Do you realize how small everything would look on a 27" screen at a resolution of 5120 x 2880? As Nick stated in his reply, it's the pixel density which gives the great clarity and sharpness to the screen. Programs enhanced for the retina display will take advantage of that.
 
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Well a lot of things can play into the looks of an image on any display.
For example a normal 1920 x 1080p LCD display used on most computers including my own is only 72ppi or about. However the 5k retina has around 300ppi.
So if you take a photo and compress it down to 72dpi, then show it on a retina display. You will not notice any difference what so ever. But if your a photographer as I am, or aspire to be.. LOL.. The photos I take and would then look at on a retina display would be much sharper. This is because my images are set to 240dpi. Now if I was to take my photo and show it on the retina and the other displays, you would seriously notice a difference.
But also this will make on screen fonts smooth as butter.
Now its likely the Mac Shop had the resolution turned down to keep things looking larger on the retina display. To small of looking stuff on a display could discourage none tech savy users from wanting it.
But for myself, I want this as I can make everything smaller and fit more applications on the screen.
But yes the screens native resolution is in fact 5120x2880, which is like having 5 1920x1080p LCDs on one screen.
 
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Points v pixels

Are you kidding? Do you realize how small everything would look on a 27" screen at a resolution of 5120 x 2880? As Nick stated in his reply, it's the pixel density which gives the great clarity and sharpness to the screen. Programs enhanced for the retina display will take advantage of that.

Thank you Nick and chscag for your replies!

I do understand that UI controls, fonts, etc. would look too small at that resolution. However, surely in Mac OS you could customise icon sizes, system font sizes, etc.? I'd be surprised if you can't, however, I concede that this is combersome and some programs might have their own (non-customisable) fonts or UI controls. I believe for this reason Apple's retina support in Mac OS has gone the route of distinguishing between Points and native pixels - I found the explanation under Mac OS X High-dpi Support helpful.

A pixel is only a real pixel if you can address it individually, which according to High Resolution Guidelines for OS X seems to be possible ("...use points most of the time, but there are instances when you might need to know how points are mapped to pixels. For example, on a high-resolution screen, you might want to provide more detail in your content...").
So, I'll try to explain better what I mean:

If I'm displaying a photo at 100%, then the color of one pixel in the image data should be painted to one pixel of the screen - that is the case in anything from old DOS programs to image viewing programs in all sorts of Windows versions, OS/2, and Ubuntu (I've been around ;-). I have never come across a different meaning of 100% (or 1:1). So, if the Mac has 5120x2880 pixels and at 100% I can only see a quarter of a 5K image, then "Preview" is stretching 1 pixel from the image across 4 native pixels, which is not making it any sharper, only bigger, and essentially wasting the high display resolution.

The way I see it, the problem is that at least this "Preview" program simply maps image pixels to Points, rather than native pixels, which sounds like it's not "enhanced for the retina display", which leads me to ask:
  • Why is something that is part of the latest Mac OS not enhanced for the retina display? Has Apple not got around to it yet?
  • Which programs are enhanced for the retina display, i.e. which programs are there that recognise that an image should be displayed 1 pixel per 1 pixel for best sharpness and detail, regardless of Point resolution?

Again, many thanks in advance for any replies - I do have a fair bit of experience with computers and work in IT, but I'm a complete newbie when it comes to Mac, because I've never had a Mac yet!

Cheers,
Paul
 

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Why is something that is part of the latest Mac OS not enhanced for the retina display? Has Apple not got around to it yet?

Which programs are enhanced for the retina display, i.e. which programs are there that recognise that an image should be displayed 1 pixel per 1 pixel for best sharpness and detail, regardless of Point resolution?

Actually, Apple has enhanced OS X for the retina display with the release of Yosemite. However, you have to remember that not everyone is using a Mac which sports a retina display. If Apple would enhance OS X only for the retina display, that would leave many other users who are using third party monitors or older Macs without a retina display in the dark. (so to speak)

As far as other programs enhanced for the retina display - you can check which apps are enhanced for the retina by checking their specs in the Mac App Store or by going to the developers web site.
 
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Well a lot of things can play into the looks of an image on any display.

Thanks Exodist,

those are good points and led me on to find out about Apple's "Points" vs. pixels.

I haven't come across an image viewing program where the dpi in an image's EXIF data takes precedence when you set the display to 100%, i.e. 1:1. At the 100% setting, it should on purpose ignore any dpi setting and map 1 pixel to 1 pixel.
To be honest, I've always ignored dpi, because in any image viewing program you as the user chooses the scaling, e.g. "fit screen" or 100% or 200%, etc., and I don't print my photos.

However, I don't think dpi is the issue, I think the real issue is that the Preview program maps pixels to Points, which in the case of the retina iMac stretch across 4 real pixels, and I suspect the reason is that it has not yet(?) been enhanced for the retina display - see my previous post.

As for fonts - each has their own resons for high res, I'm fine with fonts even on a 1024x768 display, I'm after the high res only for photos. I can get smooth fonts in Windows using Microsoft's ClearType technology, but that doesn't magically make it a high-res display ;-)
 
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Actually, Apple has enhanced OS X for the retina display with the release of Yosemite. However, you have to remember that not everyone is using a Mac which sports a retina display. If Apple would enhance OS X only for the retina display, that would leave many other users who are using third party monitors or older Macs without a retina display in the dark. (so to speak)

Isn't solving that issue exactly why Apple introduced the concept of "Points"? The "Points"-resolution is used for UI elements, etc., so they are not unduly small on retina displays, but a program like Preview should map the pixels of the displayed image to pixels on the screen - it's as simple as that and would work for both retina and non-retina, the image itself (and only the image) would simply use the native resolution of the display.

I'm sorry, I fail to see the problem with that, especially when most of the time you'd display an image scaled to fit the window anyway.

Cheers,
Tom
 

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But yes the screens native resolution is in fact 5120x2880, which is like having 5 1920x1080p LCDs on one screen.

Depending on what was actually meant by this statement…and how someone reads it…it can mean two things:

1. More screen real estate.
2. More pixels.

If the "resolution math" is done (previous 27" iMac display vs. the 27" iMac retina display)…here are the number of pixels each display has:

2560 x 1440 = 3,686,400
5120 x 2880 = 14,745,600

14,745,600 / 3,686,400 = 4

As can be seen…the 27" iMac retina display has 4x the number of pixels as the previous "regular" 27" iMac display.

If both iMac's (2013 regular 27" iMac and 2014 27" retina iMac)…are set to their native resolution and are positioned side by side…both displays will have exactly the same amount of "screen real estate". The 27" retina iMac will not be able to display any more information than a regular 27" non-retina iMac.

The 27" retina iMac is not like having five 1920 x 1080 displays on one screen…since this implies (the way I read it) that you can see the same amount of screen real estate as five 1920 x 1080 displays on one 27" retina iMac display. This is not true.

The retina display technology is about crispness & clarity…it's not about more screen real estate. As I mentioned above…a 2014 27" retina iMac (at it's native resolution) does not display any more "stuff" than the previous generation 27" iMac (2560 x 1440). The 27" retina iMac simply have more pixels for greater clarity & crispness.

If we were talking pixels…the 27" retina iMac actually has more pixels than SEVEN 1920 x 1080 displays:

1920 x 1080 display pixels: (1920 x 1080) x 7 = 14,515,200
27" retina iMac pixels: 5120 x 2880 = 14,745,600

- Nick

p.s. The other advantage to the 27" retina iMac display (or any retina display)…is when things are "zoomed in"…things stay clearer & crisper on the retina displays…due to their greater pixel density.
 
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If both iMac's (2013 regular 27" iMac and 2014 27" retina iMac)…are set to their native resolution and are positioned side by side…both displays will have exactly the same amount of "screen real estate". The 27" retina iMac will not be able to display any more information than a regular 27" non-retina iMac.
The problem is that you don't/can't(?) set a Mac to a native resolution you set it to a Point resolution - nicely illustrated in "Points vs Pixels" (article from Apple's Mac Developer library). And because 1 point is 4 native pixels on the retina iMac, that's why they display the same amount of information.

If you would set both to their true native resolution (there seem to be some apps that can do that), then on the retina 27" you would have 4x the screen real estate and every window would be physically half as wide and half as tall as on the non-retina 27".
That seems not what Apple wants, probably because then all UI elements become ridiculously small, so I'm guessing that's why the concept of "Points" resolution. However, where you do want pixels to map to pixels and not to Points is when displaying hi-res images, e.g. photos - this is even explained in Apple's own article under "Image Representations Are Ideal for High Resolution".
So that's why I don't get why the Preview application scales a 5k image to Points and not to pixels at 100% - the only explanation is that Apple hasn't gotten around to "optimising it for retina"!
 
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Hi,

I am thinking of buying a 27" retina iMac (my first Mac) mainly so I can finally look at photos at 100%.
Yesterday I had a bit of a play with one in a shop, but when I bring up a 5k image (5120x2880) in Preview and select 100% view (1:1), it only shows 1/4 of the image, and scroll bars, essentially using four native pixels for each single pixel from the image, rather than "pixel for pixel".

I have not owned a Mac (yet ;-) and every image viewer in any other OS I've used shows images at 1 pixel for 1 pixel at "100%", so I was quite confused.
So I checked the resolution in the preferences and it is set to 2560x1440 ("best for retina") and I cannot change it to 5120x2880. Confused, I then read up on e.g. how points and pixels work in Mac OS and understand now that Mac OS uses a concept of "Points" for system resolution to keep the apparent size of UI elements, font, etc. at a reasonable size, since they would be tiny if displayed pixel-for-pixel on a retina display.
Fair enough, but that article rightly goes on to say "Image Representations Are Ideal for High Resolution", i.e. a good case to use pixels and not Points. I assume that is what we're talking about when some people mention whether apps are "enhanced for the retina display", so it seems to me like Preview is not, even though it's part of the version of OS that supposedly fully supports retina displays!

To cut a long story short, it seems obvious to me that at 100% pixel-for-pixel, I should see a 5k image fill the screen, but I see how the Points of the "virtual screen" confuse the issue.

Questions:
1) Is this because Preview has yet to be updated/enhanced, or is Preview sticking to Points for backwards-compatibility?
2) If the latter, is there any way to get Preview to display an image using the full resolution, and not just Points resolution?
3) If not Preview, what else? This may be irrelevant to some people, but for me the main reason for buying the iMac is to display photos at full res, pixel for pixel - if I can't make use of the native 5120x2880 resolution for that, then it's pointless for me (don't care much whether fonts are smoother).

I am sure I'm missing something fundamental here, though, because a) I'm new to Mac, and b) it makes no sense to tout the 5120x2880 resolution as a big selling point and then not be able to fully use it!

Any help very much appreciated, as this is turning my eagerness and looking forward to buying a Mac to confusion and doubt.

Thanks!
Paul
 

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Let's keep this all together as one thread. No point in starting another thread for a question which is basically the same topic as your original thread. Threads have been merged together.
 

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The problem is that you don't/can't(?) set a Mac to a native resolution you set it to a Point resolution - nicely illustrated in "Points vs Pixels" (article from Apple's Mac Developer library). And because 1 point is 4 native pixels on the retina iMac, that's why they display the same amount of information.

If you would set both to their true native resolution (there seem to be some apps that can do that), then on the retina 27" you would have 4x the screen real estate and every window would be physically half as wide and half as tall as on the non-retina 27".

You're missing my point. The "native resolution" for the 27" retina iMac is 5120 x 2880…and the "native resolution" for the 27" non-retina iMac is 2560 x 1440. This gives the 4:1 pixel density that Apple wants us to use to get the clarity & crispness of the retina display.

At these settings…both 27" display's (retina and non-retina) will display the same amount of screen real estate.

- Nick
 
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You're missing my point. The "native resolution" for the 27" retina iMac is 5120 x 2880…and the "native resolution" for the 27" non-retina iMac is 2560 x 1440. This gives the 4:1 pixel density that Apple wants us to use to get the clarity & crispness of the retina display.

At these settings…both 27" display's (retina and non-retina) will display the same amount of screen real estate.

- Nick
Perhaps our definitions of screen real estate are different?

If I have an image (or window for that matter) that is 2560 x 1440 pixels in size, then on the non-retina iMac, it will physically be 27" across. On the retina iMac, if you would/could set its resolution to 5120x2880, that image/window would physically be 13.5" across and if you wanted, you could fit four of them on the screen. That, to me, is more screen real estate.

The issue is that the retina iMac is set to 2560 x 1440 as the "best for retina" resolution and merely uses the extra pixels to provide smoother fonts, etc. because it has more pixels to use for interpolating, but it spreads the abovementioned 2560x1440 image/window across the whole 5120x2880 pixels, using 4 pixels for each image/window pixel.

What I'm asking for is that image viewing programs like Preview recognize that there are 4x as many pixels as the "virtual screen" points and makes use of them - this even seems to be recommended in Apple Developer Library's own article under "Image Representations Are Ideal for High Resolution"!
 

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Perhaps our definitions of screen real estate are different?

If I have an image (or window for that matter) that is 2560 x 1440 pixels in size, then on the non-retina iMac, it will physically be 27" across. On the retina iMac, if you would/could set its resolution to 5120x2880, that image/window would physically be 13.5" across and if you wanted, you could fit four of them on the screen. That, to me, is more screen real estate.

This isn't the way it works. When you have the retina iMac set to 5120 x 2880 you have exactly the same screen real estate as an older 27" iMac set at 2560 x 1440.

Using your example above...if you had an image or window that was 2560 x 1440. With a retina iMac set at 5120 x 2880 or an older 27" iMac set at 2560 x 1440...this 2560 x 1440 image or window would take up the same exact area on both displays.

What you get with the retina display is NOT more screen real estate...what you get is 4x the pixel density...which gives a sharper & crisper display. If you don't believe me...go to an Apple Store...and look at the 27" iMacs retina & non-retina...and you will see what I mean.

I'll give you a second example. Non-retina iPad vs. retina iPad (both 9.7" display's). The resolution on a:

- non-retina iPad = 1024x768
- retina iPad = 2048x1536

- total pixels non-retina iPad = 786,432
- total pixels retina iPad = 3,145,728

3,145,728 / 786,432 = 4

As you can see...the retina iPad has 4x the total pixels.

Now...if you were to look at the non-retina iPad and retina iPad side by side...the "screen real estate" is EXACTLY the same. The retina iPad just looks somewhat sharper & crisper.

This works EXACTLY the same way with iPhones (retina & non-retina iPhones)...and 13" MacBook Pro's (retina vs. non-retina).

In all these examples:

- retina iPhones
- retina iPads
- retina MacBook Pro's
- and finally the 27" retina iMac

The retina technology is all about sharper & crisper images on the display's...not more screen real estate. And the advantage of the retina display's is...when you zoom in...the images stay sharper (less pixelated) than the same zoom setting on a non-retina device.

- Nick
 

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A picture is worth a 1000 words. Here's another way (using a photo) of what I've been trying to say in words throughout this thread.

The photo (below) has exactly the same physical dimensions (let's say for arguments sake that it's 1" x 1" area on the display). The non-retina display image is on the left...the retina display image is on the right. The difference is the pixel density (sharper & crisper) with the image on the right:

Confronto-retina-ipad-900.jpg


- Nick
 
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A picture is worth a 1000 words. Here's another way (using a photo) of what I've been trying to say in words throughout this thread.

T.............
- Nick

Excellent example.



IS there even a way to scale the user interface in OSX?
I know I can scale the icons, font (increase the pt size) and dock. But I see nothing on the window manager or the dialog components.

But as per they keynotes they claimed it had more desktop real-estate as one video they showed with a pro photographer claiming to have Final Cut and other programs open at the same time on the screen and could view them all together at the same time. Without any being behind other windows or minimized.

So this is turning out to be confusing and we all need some real clarification. One huge reason I am wanting a 27" retina was more screen real-estate. If it doesn't offer it, then its a waste of money to me.
 

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So this is turning out to be confusing and we all need some real clarification. One huge reason I am wanting a 27" retina was more screen real-estate. If it doesn't offer it, then its a waste of money to me.

You're not going to get any more real estate but what you are going to get is greater clarity with the increased pixel density. The OP asked how come the screen is not set to its native resolution and I think you probably saw my answer as to why that would not be practical.

However, for someone like yourself who is into photography, the retina iMac in my opinion would be a great tool to use. It's not a Mac Pro, but like I mentioned to Nick, you can call it a poor man's Mac Pro. ;)
 

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IS there even a way to scale the user interface in OSX?

Assuming I understand the question…I think that this Apple document may explain (see the photos in the article below)…it even includes info for the new 27" retina iMac::)

Frequently asked questions about using a Retina display - Apple Support

But as per they keynotes they claimed it had more desktop real-estate as one video they showed with a pro photographer claiming to have Final Cut and other programs open at the same time on the screen and could view them all together at the same time. Without any being behind other windows or minimized.

I'm not sure I saw this keynote…but this sounds like a "standard" ability of the 27" display. It is so large…that you can easily have two apps (two app windows) open at the same time (not over-lapping).

Heck…this can be done on a 1920 x 1080 display. So easily able to do on a 2560 x 1440 display.:)

So this is turning out to be confusing and we all need some real clarification. One huge reason I am wanting a 27" retina was more screen real-estate. If it doesn't offer it, then its a waste of money to me.

I see it two ways:

1. The 27" retina iMac display real estate would be just like an iPhone, iPad, or retina MacBook Pro display's. You don't get more screen real estate…you get better visual quality.

2. If the 27" retina iMac's display resolution can be "scaled" in some way (see Apple article above) to provide more screen real estate. Then that would mean that the "stuff" on the desktop could get shrunk so small…it would be very difficult to see. And the "retina display quality" would be lost…since the 4x pixel density would no longer be present.

- Nick
 
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Assuming I understand the question…I think that this Apple document may explain (see the photos in the article below)…it even includes info for the new 27" retina iMac::)

Frequently asked questions about using a Retina display - Apple Support

..........
- Nick

So it can make the UI smaller. Which is good, thats what I wanted. It does this by changing the screen resolution. But what I was getting at was in Windows (at least up to 7 were I stopped using it) you could scale the UI without changing the screen resolution. Its more of a accessibility feature for those like myself who are blind as a bat.. LOL

As for myself, I would just slide over the slider to more space to increase the resolution to max, then go back an raise the font size so I can read whats on the screen. This may actually make Yosemite look better.. LOL
 

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