Results: Viewing Angles And Uniformity
To learn how we measure screen uniformity, please click here.
Here is TN’s one failing compared to IPS: off-axis viewing. Fortunately, the IX2850 is not quite a bad as the two other 28-inch Ultra HD screens we photographed. The green shift to the side is about the same. Look at the darkest steps, though. You can still see a difference between the zero- and 10-percent levels. We’re not sure why this is the case since the parts are the same. Our best guess is that Planar’s anti-glare layer sits closer to the TFT, resulting in a smaller air gap and less optical diffraction as the eye moves off-center. In the vertical plane, there is a lot of detail loss. But again, you can still see all the steps. It’s definitely better than most of the TN displays we’ve tested.
Screen Uniformity: Luminance
The black field result might support our theory about the tightly-mounted anti-glare layer. We saw this on the PXL2790MW as well. That screen has no gap whatsoever and the added pressure can cause light bleed. It’s not as bad with Planar’s Ultra HD screen, though. We only saw a slight hot-spot in the center. The surrounding zones look just fine.
Here’s the white field measurement:
The white field test shows a much better result, revealing no issues. The meter says there’s a hot-spot in the center, but it’s not visible to our eyes.
Screen Uniformity: Color
A 1.24 Delta result in the color uniformity test puts the IX2850 ahead of most of our monitor test database. It even beats out some that have uniformity compensation features. If you choose Planar as your 4K display, you needn’t worry about quality control issues. This is a very well-made monitor.
Pixel Response And Input Lag
Please click here to read up on our pixel response and input lag testing procedures.
For those who want to game at 4K, the fastest displays are the 28-inch TN models. Their screen draw times are just a little quicker than the IPS-based competition. Even though the Dell P2815Q wins this particular contest, remember that at its native resolution, it can only run at 30Hz.
Here are the lag results:
The 60Hz refresh rate available from Asus and Planar obviously make a difference in the input lag result. We think there’s also something unique about Dell's control board, since its input lag score is one of the highest we’ve ever recorded. Gaming on the IX2850 should be a decent experience if you can live without G-Sync or high refresh rates. Still, your video card (or cards) has its work cut out for it to maintain smooth performance.