Brightness And Contrast
To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test Monitors and TVs. Brightness and Contrast testing is covered on page two.
Uncalibrated – Maximum Backlight Level
There's only one other 5K display currently on the market, HP's Z27q, and it's included in our comparison today. The remaining monitors are Ultra HD IPS, VA and IGZO panels. We have the ViewSonic VP2780-4K, NEC's EA244UHD and PA322UHD, and Philips' BDM4065UC. All are premium products, except for the Philips monitor, which is an impressive value and our current contrast record-holder.
The UP2715K easily beats its claimed peak brightness of 350cd/m2. There is more than enough light for any task and it would probably work well outdoors, though the shiny screen coating could hamper that a little.
It's almost unfair to include the Philips and its VA panel in this comparison because of its super-low black levels. The Dell is mid-pack with the rest at a respectable .3561cd/m2.
Contrast in the default Color Temp mode is pretty good at 1014.1:1. This is good performance for an IPS panel and visually indistinguishable from all but the Philips display.
Uncalibrated – Minimum Backlight Level
The backlight drops to a low 42.7606cd/m2 at its minimum setting. 50cd/m2 can be achieved by turning the 100-step Brightness slider up to 21.
The black level stays in the same place relative to the other displays. It looks like the UP2715K has consistent contrast throughout its brightness range.
Minimum contrast is still above 1000:1 and moves the Dell up one spot in the results. It should be noted that all the above tests were performed in Color Temp mode. The Adobe and sRGB presets, which we recommend, have lower contrast at just under 800:1. They are more color-accurate though as you'll see later.
After Calibration To 200cd/m2
We performed the calibrated contrast tests using the UP2715K's Custom mode. That gave us great grayscale tracking, fair color gamut results and a slight increase in black levels; enough to send it to last place by a small margin.
Calibration has a negative impact on contrast but we think the increase in accuracy is worth the sacrifice. The picture still looks great to us, thanks to its incredible sharpness and a complete lack of visible pixel structure.
ANSI Contrast Ratio
Our sample showed a little extra brightness in the corners, which accounts for the drop in ANSI contrast. This isn't a deal-breaker by any stretch and other examples would measure differently than ours. 615:1 is slightly below average for the IPS panels we've tested.