Results: Pixel Response And Input Lag
To perform these tests, we use a high-speed camera that shoots at 1000 frames per second. Analyzing the video frame-by-frame allows us to observe the exact time it takes to go from a zero-percent signal to a 100% white field.
The pattern generator is placed at the base of the monitor so our camera can capture the precise moment its front-panel LED lights up, indicating that the monitor is receiving a video signal. With this camera placement, we can easily see how long it takes to fully display a pattern after pressing the button on the generator's remote. This testing methodology allows for accurate and repeatable results when comparing panels.
Here’s a shot of our test setup. Click on the photo to enlarge.
The brighter section of the camera’s screen is what appears in the video. You can see the lights of the pattern generator in the bottom of the viewfinder. We flash the pattern on and off five times and average the results.
The E271i is the snappiest monitor we’ve tested recently.
However, the more important figure is input lag. Again, these results should only be compared to one another, and not with the numbers posted by other publications that use different testing methods.
The HP is again, one of the faster monitors we’ve tested. It’s merely a coincidence that the other screens we chose for the comparison are just a tiny bit faster. Sixty milliseconds (40 ms input lag plus 20 ms draw time) puts the E271i in our top tier for absolute input lag. At this performance level, very few gamers would notice any delay in their control inputs. The only way to significantly improve on these numbers is to buy a high-refresh rate screen; which is a technology we'll also be reviewing very soon.