How to access High Resolution on Studio Display without shrinking everything

If you run a 27" 5K Studio Display in Retina "like 2560x1440" mode, text and objects will be the same size that they would be on a regular 27" 2560x1440 display.

Retina-aware applications – these days, most of them – will use the 2560x1440 as a sizing / workspace guideline, but will fill in photo areas with high detail. LIkewise, macOS will take advantage of the fact that the 5K screen has four small pixels (a 2x2 grid) for every one pixel that a 2.5K display has. It will draw letter shapes more precisely.

The bottom line is that the 5K resolution will go towards sharper text and images, rather than towards cramming lots and lots of tiny text strings and objects onto the screen. You can set the scaling to other levels … and some people like to run at higher than "like 2560x1440". But it's a mistake to think that unless you're using the screen flat-out at 5120x2880 pixels with no scaling, the resolution isn't offering any advantage.

Nothing you can do to change that. That is why Apple uses a default resolution larger than the spec so you can see it. Most monitors do it that way. Even my 32" 6K XDR defaults to 3008 x 1692 but the PPI is so high that it is still very sharp.

Basically, the Retina model – where the LCD panel has one resolution, and the Displays {Preferences/Settings} has a different one – is a way to get around the issue that applications have almost always treated "pixels" as synonymous with "physical size." In the old days, when there were fairly small variations in DPI, there was not a lot of pressure to change this model. So you might see old 15" MacBook Pros offered with two different screen resolutions – with the understanding that if you chose the "hi-res" screen, you'd see more text at one time, but it would be smaller.

With displays that have Retina-level PPIs, the idea of using all of the pixels to cram more and more stuff onto the screen becomes untenable. That would be true even if there were no Retina "resolutions" in Display {Preferences / Settings} – even if there were more direct text/object size controls, instead.

There is an inherent tradeoff between

• The physical size of a screen,
• The physical size of individual text strings and objects ("stuff"), and
• The amount of "stuff" you can cram onto the screen ("workspace")

The physical size of individual text strings and objects matters because we don't all have microscopic vision like Kryptonians do in the comics. So with high-resolution screens, it makes sense to put some or all of the extra resolution towards more detail rather than towards workspace at the cost of readability.

Think of this way: for a long time, it's been possible to print books with much more PPI resolution than a Retina screen has. Yet somehow, publishers aren't rushing to put out books printed entirely using 3-point fonts – and people aren't rushing out to buy them.