Readers Write: How does the Monitor Face-Off work?

Let's take a closer look at two key features of a monitor's performance: the display of different shades of grey and the input lag.

Subject: Monitor Face-Off: Greys Hello, I'm writing to ask for a couple of details that might seem obvious to you, but that beginners like me sometimes struggle with! In the Monitor Face-Off, one of the tests users can choose from is 'greys', which illustrates what different shades of grey look like on the monitor.  On the top row, you have the 'default colours', and you go on to explain that 'the top row shows the greys displayed by the screen with the best possible settings available without calibration, while the bottom row shows the greys that should have been displayed in ideal conditions.'  To me, discovering your site for the first time, that means that the top row shows the best results you managed to get using the onscreen menus but that you didn't actually calibrate it.  I'd still like to check though, so I know I've understood it properly. Something else I've been wondering about is response time.  When comparing the Samsung 2233rz and XL2370, I found it hard to tell the difference between the former's stable input lag of around 12 ms, and the latter, where it varied from 0 to 33 ms (two whole frames behind!), with an average of 7 ms.  What is the difference between them?  The 'What should I look for?' section doesn't make it especially clear …

First of all, a little bit of background: the Monitor Face-Off was thoroughly updated at the start of the year to make it compatible with the one that we use for TVs.  When we made the change, we tested as many monitors as we could using the new system, but, as you can imagine, we didn't have every single one of them to hand.

Until 2010, the greys test card showed the monitor's default settings, but with the new test procedure, we changed that to show the results produced using the best available settings using the onscreen menu, but without calibrating the monitor.  If we used the results after calibration, then all of the monitors we tested would have the same perfect score.

As for input lag (which is not to be confused with response time), nothing has changed, but I can see why there are still a few questions.  It's the time it takes for a display to receive and process the signal that your computer sends it.  If you look at the TV Face-Off, you might notice that it often takes televisions longer than computer monitors.  That's because they include graphic correction chips that actively process the signal before it's displayed, something that monitors don't do.


In practice, though, as long as the input lag is below four frames, or 66 ms, then it will be invisible to the naked eye, and so won't be a problem for multiplayer games.  Beyond that, though, it starts to be a problem and can hold you back.  These days, though, not many monitors break this barrier, and the vast majority actually have under two frames of input lag.  The last one that did have noticeable input lag was the Dell 2408WFP, which we tested back in 2008.  It had an input lag of five frames.

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