4K iMac to 4K or 2K external monitor?

Posted:
in Genius Bar
Hello all,

Last fall, I just got a 2019 Retina 4K iMac 21.5 inch, on Mojave with Intel Core i3 and 16 GB of RAM. Graphics card: Radeon Pro 555X 2 GB. This replaces my 2010 iMac which is being retired. 

I do graphic design and digital art using the Wacom, when necessary, and have been looking into adding an external monitor to extend the desktop for multitasking and reference. I checked the scaled display options and it shows 2560 x 1440 over 'more space' while 'larger text' shows 1280 x 720. A friend recommended I get a 4K display to stay native without scaling too much. Right now, my iMac can display 4096 x 2304 pixels. I'll be doing the main work on the iMac while the second screen will be used for extending the desktop and act as reference, palettes, chatting ( without having to cram the screen ), video ( the iMac audio isn't that great so an external monitor's audio should be far better for this ), and whatnot. 

Can I get away with getting a 2.5K external monitor at the risk of scaling down to that scale or just straight out to 4K? I suspect it's the latter even though it'll cost more as I'm looking into BenQ, ViewSonic, LG or Samsung models probably around 25 or 27 inches. I'm aware that I'm better off using HDMI and will need an adapter to convert that to plug into the TB3/USB C port. 

The last time I did use dual displays was way back in the early 2000s with CRTs which was a neat set up but now I want to go back to that. 

Any thoughts or suggestions? Thanks! 

Comments

  • Reply 1 of 8
    Mike WuertheleMike Wuerthele Posts: 6,837administrator
    Well, for starters, don't use an adapter. Get a USB-C to HDMI cable.

    You can absolutely do what you want it to do. Unless you get the LG 4K display, you aren't going to get Retina DPI, but how much that matters depends very much, person to person.
  • Reply 2 of 8
    Sanctum1972Sanctum1972 Posts: 112unconfirmed, member
    USB-C to HDMI cable is what I was thinking of. Thanks for reminding me.

    As for the monitor, since my iMac is a 4K, does it mean I can still get away with a 2560 x 1440 resolution scaled down? I only ask because I work with Affinity apps ( migrating out of Adobe ) and do mostly digital and print art projects. Most of my work will be on the main screen but the second monitor will be an extension of the desktop screen to give me more room to move the windows out or to multi-task. Color correction is not important on the second screen but only the primary one ( the 4K iMac ). 

    Retina DPI isn't important to me let alone the scale of the projects ( ie. inches in actual print size or screen resolution if dealing with web based images ). If I do the 4K monitor, then I won't have to worry about scaling much and keep it close to native. But if I do a QHD or 2.5 K screen, then it should scale down to 2560 x 1440p at the least but not lower or it'll look skewered. 

    That's why I was looking for some feedback on experiences. So in essence, either a 4K monitor or 2.5 screen should do the trick. 
  • Reply 3 of 8
    Sanctum1972Sanctum1972 Posts: 112unconfirmed, member
    Mike,

    Some interesting updates. I just discovered that my 2019 4k iMac having a native resolution of 4096 by 2304 is also running at a default of 2048 by 1152 'pixel doubled'. Something tells me that a 2.5 K external monitor just may do the trick even though a 4K screen will also do. 
  • Reply 4 of 8
    svanstromsvanstrom Posts: 702member
    Don't know if it's me or you that's confused here, but…

    Essentially the displays are completely separate from each other; so whatever settings you have on one of them doesn't in any way influence the settings you can have for the other (within reason, meaning whatever the hardware in your computer can handle).

    So ignore the settings, and focus on what you actually need to do on that second display; and then buy according to those specs.
  • Reply 5 of 8
    Sanctum1972Sanctum1972 Posts: 112unconfirmed, member
    svanstrom said:
    Don't know if it's me or you that's confused here, but…

    Essentially the displays are completely separate from each other; so whatever settings you have on one of them doesn't in any way influence the settings you can have for the other (within reason, meaning whatever the hardware in your computer can handle).

    So ignore the settings, and focus on what you actually need to do on that second display; and then buy according to those specs.
    Thanks. I haven't bought one yet so still researching. It's likely I'll be going for a 4K Samsung screen from Best Buy going for 28 inches in size for $350. Not bad. 
  • Reply 6 of 8
    svanstromsvanstrom Posts: 702member
    My best advice is that you simply go have a look at them; and if they look good enough to you in a bright store they are probably good enough.

    I recently shopped primarily by specs, and ended up with a 24" LG monitor with "macOS Compatibility": https://www.lg.com/us/ultrafine-monitors. Absolutely beautiful monitor (but in retrospect I should have gone with a 27"), and it's very convenient with that proper Mac-compatibility.
  • Reply 7 of 8
    Sanctum1972Sanctum1972 Posts: 112unconfirmed, member
    svanstrom said:
    My best advice is that you simply go have a look at them; and if they look good enough to you in a bright store they are probably good enough.

    I recently shopped primarily by specs, and ended up with a 24" LG monitor with "macOS Compatibility": https://www.lg.com/us/ultrafine-monitors. Absolutely beautiful monitor (but in retrospect I should have gone with a 27"), and it's very convenient with that proper Mac-compatibility.
    If only the local stores allow customers inside to do that during COVID-19. Unfortunately, it's impossible to walk into a Best Buy these days but only to browse online and buy to order for delivery or curbside pick up. The LG monitor you just linked me to looks nice and the 24 inch version appears to be close to $700 on the market. The monitor I was looking at is this: https://www.bestbuy.com/site/samsung-ur55-series-28-ips-4k-uhd-monitor-dark-gray-blue/6386391.p?skuId=6386391

    Samsung 28 inch IPS 4K at $350. My iMac has a max resolution of 4096 x 2304 natively but by default is going at 2048 x 1152 currently the way it was set up the moment I fired it up the first time. Although with 'more space', I can go up to 2560 x 1440 if I wanted to natively but that would make text a bit smaller. I have astigmatism wearing glasses and am far sighted/near sighted in each eye ( weird I know ) as things get blurry close to my eyes without my glasses but can see far without them. 

    I'm still researching around  because I want to make sure the 4K Retina 21.5 iMac screen can extend to the secondary monitor with no issues. I've done it before almost 20 years ago with CRTs but these days, it seems a bit more complex. If I'm going to do graphic design /digital art work mainly on the iMac and use the secondary monitor for reference or multi-tasking with chat, file management, writing, etc, then I wouldn't need a monitor that's overkill. 

    But since it's currently going at 2048 x 1152, I assume an external 4K monitor would allow me to either scale up to the max or down. The Samsung appears to be the cheapest 4K monitor I've seen at 28 inches ( quite a big one but probably practical if I need to see properly ). This monitor can go up to 3840 x 2160 from what I see listed. Many of the 2K ( or below 4K resolution ) monitors on Best Buy are sold out and some cost more than that Samsung I was looking at. 

    If I'm currently at 2048 x 1152, wouldn't a QHD ( 2560 x 1140 ) external make sense? Something like this: 
    https://www.bestbuy.com/site/viewsonic-vx2478-smhd-24-ips-led-qhd-monitor-black-silver/5660600.p?skuId=5660600

    EDIT: I just realized something. Does it depend on whether I'm using HDMI or Display Port? I'm starting to read how Display Port is superior to HDMI for resolution flexibility, however it shouldn't matter? I'm aware that I need a HDMI to USB C or a Display Port to USB C to pull this off. 
    edited May 2020
  • Reply 8 of 8
    svanstromsvanstrom Posts: 702member
    svanstrom said:
    My best advice is that you simply go have a look at them; and if they look good enough to you in a bright store they are probably good enough.

    I recently shopped primarily by specs, and ended up with a 24" LG monitor with "macOS Compatibility": https://www.lg.com/us/ultrafine-monitors. Absolutely beautiful monitor (but in retrospect I should have gone with a 27"), and it's very convenient with that proper Mac-compatibility.
    If only the local stores allow customers inside to do that during COVID-19. Unfortunately, it's impossible to walk into a Best Buy these days but only to browse online and buy to order for delivery or curbside pick up. The LG monitor you just linked me to looks nice and the 24 inch version appears to be close to $700 on the market. The monitor I was looking at is this: https://www.bestbuy.com/site/samsung-ur55-series-28-ips-4k-uhd-monitor-dark-gray-blue/6386391.p?skuId=6386391

    Samsung 28 inch IPS 4K at $350. My iMac has a max resolution of 4096 x 2304 natively but by default is going at 2048 x 1152 currently the way it was set up the moment I fired it up the first time. Although with 'more space', I can go up to 2560 x 1440 if I wanted to natively but that would make text a bit smaller. I have astigmatism wearing glasses and am far sighted/near sighted in each eye ( weird I know ) as things get blurry close to my eyes without my glasses but can see far without them. 

    I'm still researching around  because I want to make sure the 4K Retina 21.5 iMac screen can extend to the secondary monitor with no issues. I've done it before almost 20 years ago with CRTs but these days, it seems a bit more complex. If I'm going to do graphic design /digital art work mainly on the iMac and use the secondary monitor for reference or multi-tasking with chat, file management, writing, etc, then I wouldn't need a monitor that's overkill. 

    But since it's currently going at 2048 x 1152, I assume an external 4K monitor would allow me to either scale up to the max or down. The Samsung appears to be the cheapest 4K monitor I've seen at 28 inches ( quite a big one but probably practical if I need to see properly ). This monitor can go up to 3840 x 2160 from what I see listed. Many of the 2K ( or below 4K resolution ) monitors on Best Buy are sold out and some cost more than that Samsung I was looking at. 

    If I'm currently at 2048 x 1152, wouldn't a QHD ( 2560 x 1140 ) external make sense? Something like this: https://www.bestbuy.com/site/viewsonic-vx2478-smhd-24-ips-led-qhd-monitor-black-silver/5660600.p?skuId=5660600

    EDIT: I just realized something. Does it depend on whether I'm using HDMI or Display Port? I'm starting to read how Display Port is superior to HDMI for resolution flexibility, however it shouldn't matter? I'm aware that I need a HDMI to USB C or a Display Port to USB C to pull this off. 
    The ideal port is often the same one at both ends (with matching specs); so if you have a Mac with Thunderbolt 3, then a monitor with Thunderbolt 3 would match up nicely.

    Someone that knows their stuff will perhaps somewhat disagree with me on that one, because that Thunderbolt 3-port will quite happily output other formats just as good as a "native" port of some other standards; but unless a person happens to be one of those "someones", then the matchy-matchy is a good approach to not accidentally introduce some sort of flaw. (And as much as the T3/USB-C world is awesome, there's a bunch of mistakes one can make with subpar equipment; like accidentally limiting both the resolution and refresh rate of external monitors with the HDMI-port in some USB-C hubs.)

    If you look at the specs of that LG monitor I got you'll see:
    • Two Thunderbolt 3 (In-85W PD /Out)
    • Three USB-C Ports
    With my main computer being a MacBook Pro that means that I have one power cable to the monitor, and then from it I have a single cable to my MBP (which both connects it to the monitor, and powers the MBP); and I also have one cable to power an iPad (which I thanks to Sidecar use as a third display: https://support.apple.com/en-us/HT210380 ). 3 cables in total, to power and connect one computer and two external displays.

    So if you "invest" in the right ports you longterm could save yourself a lot of trouble with not only future compatibility, but also the number of cables you have to fight with having on/around your desk.
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