Confused about scaling on 5k iMac

I too just bought a 5K iMac 27" (with a Radeon Pro 580 graphics card) and am also puzzled by the resolution schemes. When you go to system preferences>display you can choose "scaled" but the highest resolution you are "offered" is 3200 x 1800 (more space as it is called). Why can't I choose for the native resolution 5120 x 2880?

It's a new machine, so you have at least 90-days of free phone support. Contact Apple's Support and they'll handle all of you questions. BTW, I strongly recommend getting AppleCare Protection Plan. It's the best warranty policy available for desktop machines and gives you three years of free phone and repair support.

27" i7 iMac (Mid 2011) refurb, OS X Yo (10.10.1), Mavs, ML & SL, G4 450 MP w/10.5 & 9.2.2

I'm sorry to dig up this old thread, but the problem still exists and I thought I'd chime in instead of starting a new thread.

I got my 5K iMac a couple of days ago, the newest i7 version. And just as you guys, I've found that the scaling is very weird. I first noticed it when I tried to play some of my own 4K movies, recorded from Panasonic and Sony cameras, and saw that they didn't scale correctly. I've tried both VLC and Quicktime Player.

In Quicktime Player, the Inspector (or what it's called in English; I'm using the Swedish version) said correctly that the format was 3840 x 2160 pixels, but the "actual size" was "1920 x 1080 pixels (half resolution)"..! On the screen, the Quicktime window took up around 75 of the screen, which should be pretty close to 4K resolution. But Quicktime didn't know.

I then tried to create an image from scratch in Photoshop, making it 2560 x 1440 pixels – or exactly one quarter of the screen resolution of the 5K screen (which is 5120 x 2880 pixels). In Photoshop, the image (when viewed at 100 percent) took up one quarter of the screen. Just as it should be.

I then exported it as a png image file and opened it in Preview. Even though I chose "actual size", the image seemed to fill the entire screen. I've tried using both options that Cbuzio linked to previously, but with the same result.

This is infuriating! If I have an image or a movie that's 100 by 100 pixels, I expect it to cover 100 by 100 pixels on the screen at 100 percent, or "actual size", or whatever it is called by each program. Just like I can with my four year old iMac (with no Retina screen), and every other computer I've ever owned before.

There is nothing good about this.

/ Kiwi

OK, so this is what I've found:

If you press the Option key while you click Scaled in System Preferences > Displays, you will see additional resolutions – including 5120 x 2880. If you choose that, everything will become small, but the things that are supposed to be 100 by 100 pixels are in fact 100 by 100 pixels.

The five different resolution schemes (with the 3rd (or middle) being the standard), is almost all about the GUI (menu bar, icons, etc). Number 3, 4, and 5 all seem to have the full resolution (5120 x 2880). Number 1 and 2 do change everything to a lower resolution.

But why can't Apple give us the best of both worlds? The best solution IMHO is to have a choice where the GUI is scaled up, while each program decides for itself if it's going to scale up or not. Or is that already the case, and the programs don't make any use of it? Either way, it's still extremely irritating.

Alas, it's no better on the "other side". A friend of mine says he experienced the same with a 4K screen and Windows 10: A 4K movie was rescaled, even though the screen should've handled it just fine.

Are retina screens still too new to use properly?

/ Kiwi

Thanks for this useful information! It turns out that (indeed) the native resolution makes everything extremely small, so maybe not so practical, but at least one does have the choice between several resolutions and it can be handy one day.

I also got a new iMac 5k yesterday and noticed exactly the same thing. Quite disappointing! Selecting 'Actual Size' in Preview is pixel doubling the image and making it look awful. And iPhoto doesn't give any info about when you're at a 1:1 zoom.

However, Adobe Lightroom works beautifully and correctly displays images at 1:1. The detail is breathtaking! I highly recommend you try downloading the free trial just to see it.

What's kind of staggering is the my display now has more pixels than many of my cameras' sensors (all but my high-end Canon DSLR)! An 8 megapixel image from an iPhone 6 only fills 75% of the screen vertically, so you can see every pixel and room to spare for editing tools.

Let's hope Apple gets their act together soon on iPhoto and Preview for Retina displays -- it's kind of pathetic.

Hello Chris,

I am experiencing the same problem. I am wondering if you did get an answer to this or maybe someone else. Please help because it is very confusing. In QuickTime for example I am playing a 4k video, but it says it is playing at 2560x1440. However I'm not sure if this is true, cause changing the settings from the lowest to the highest resolution (scaling options) does not really seem to affect the sharpness and quality of my full screen video.

However I am lost on this topic.

Don't know if this helps.

2560 x 1440 is the default resolution.

For other resolutions goto System Preferences > Displays > Hold down Option Key and you should see a Detect Displays marker in the lower right hand corner.

Now change the Resolution from Best for Display to the Scaled option and you should be presented with a drop down list of available resolutions including 5120 x 2880.

Concerning the OP's question re Preview, I've found that Preview will not accommodate different resolutions. It's a one size fits all. Cn't answer re iPhoto as I don't use it but someone in that section may well have the answer or explanation.

The first section in the following link may help to better explain it's resolution:

http://www.everymac.com/systems/apple/imac/imac-aluminum-tapered-edge-faq/how-to -run-imac-retina-5k-at-full-resolution.html

I had already discovered the excellent tip seroposi suggested (saw it on an iMac 5K at an Apple Store). What's interesting is then to compare images and movies using the max (5120 x 2880) resolution, versus the 'best' scaled resolution (pixel doubled). I played a 4K movie in Quicktime at both resolutions. When I used max resolution, I could use 'actual size' and get 1:1 pixel mapping. Using 'best' scaled, I had to guess where "50%" was, since neither Preview nor Quicktime seem to give you this information. Anyway, when I took screenshots of both, I got identical pixel to pixel results...

So, this means that while most of the native Apple apps (QT, Preview,iPhoto) are displaying content correctly (i.e. not pixel doubling images & videos), the 'Actual Size' calculation is wrong and doesn't give you any easy way to get a 1:1 mapping. It's interesting that Final Cut Pro does actually know what a 100% playback looks like, even when on 'best' scaling. So clearly Apple knows how to do this. Let's just hope they fix them in future versions of these apps.

Thanks seroposi and bryston! I find this option to use the max resolution helpful. However everything is indeed crazy small. Now I compared for example a 4k video on Youtube (just for testing) and it does not matter for the quality of the video itself if you set the resolution to max (5k) or for example 1280x720 when you enter full screen. It seems like the iMac forces it to play 4k anyway. Probably the same for VLC and other programs. Can you agree to this?

However I also keep reading that QuickTime does not support playing 4k videos. An employee of Apple (support employee) told me this. And I read VLC does. What are your thoughts on that?

http://forums.macrumors.com/showthread.php?t=1837046&highlight=5k+resolution

Forgot to add that I've found VLC seems to do a better job than QuickTime.

I just got the new iMac 5K and was also having issues with Preview at 100%, but found a solution:

Go to Preview>Preferences>Images and change to this:

The text doesn't seem to make sense (the "1 image pixel equals 1 screen pixel" should be the correct option, right?) but it seems to work.

FWIW, the setting you chose will show how large the print out will be based on the resolution the printer is set to if you choose Actual Size.

The first setting will display a 1 to 1 correspondence on the screen based on the resolution of the image when viewed at Actual Size. So if you had a one inch image that is 300 dpi, it will display using 300x300 screen pixels. a one inch 72 dpi image would use 72x72 pixels on the screen and so on.