X-bit labs

Contemporary LCD Monitor Parameters: Objective and Subjective Analysis (page 10)

Category: Other

by Oleg Artamonov

[ 01/23/2007 | 02:21 PM ]

A comparison between UFO researchers and PC users who are purchasing a monitor may seem strange, yet the latter are prone to behave in the same manner at a Web forum. Most of them won’t even consider the fact that the feeling from a monitor will totally change if its resolution and size are different. Instead, they are earnestly discussing how a negligible lag of 47 milliseconds may affect the mouse pointer’s movement.

And second, people are prone to auto-suggestion. Take two bottles of beer of different brands, one cheap and another expensive, and pour the same brand of beer into them. Most people will say the beer from the bottle with the expensive brand label tastes better, but if the labels are removed – the opinions will divide equally. The problem is our brain cannot fully disengage itself from various external factors. So when we see a luxurious packaging, we subconsciously begin to expect a higher quality of the contents of such a package and vice versa. To avoid this, all serious subjective comparisons are performed with a blind test method. All the tested samples go under different numbers and none of the testing experts knows which number corresponds to which brand.

It’s the same with the input lag thing. A person who has just bought or is going to buy a new monitor, goes to a monitor-related forum to find multiple-page discussions of such horrors of the input lag as slow movements of the mouse, total non-playability, etc. And there surely are a few people there who claim they can see the lag with their own eyes. Having digested all that, the person goes to a shop and begins to stare at the monitor he’s interested in thinking, “There must be a lag because other people see it!” Of course, he soon begins to see it himself – or rather to think he’s seeing it. Then he goes back home and writes to the forum, “Yeah, I’ve checked that monitor out – it’s really retarded”. You can even read some funny posts like, “I’ve been sitting at the discussed monitor for two weeks, but it’s only now, after I’ve read the forum, that I see the lag”.

Some time ago there were video clips at YouTube in which they were moving a program window up and down with a mouse on two monitors standing next to each other and working in Desktop extension mode. It was perfectly clear that the window on the monitor with an input lag was moving with a delay. The clips looked pretty, but think: a monitor with a refresh rate of 60Hz is shot on a camera with a matrix refresh rate of 50Hz. This is then saved into a video file with a frame rate of 25Hz and this file is then uploaded to YouTube which may well encode it once again in there, without informing you. Is there much of the original left after all that? I guess, not. I saved the clip from YouTube and opened it in a video editor and watched it frame by frame. And I saw that at some moments there was a much bigger difference than the mentioned 47 milliseconds between the two monitors, but at other moments the windows were moving in sync as if there was no lag at all. So, I just can’t take this as a convincing and coherent proof.

Here’s my conclusion to this section:

A)  There is indeed an input lag on some monitors. The maximum value of the lag that I’ve seen in my tests is 47 milliseconds

B)  A lag of this value cannot be noticed at ordinary work or in movies. It may make a difference in games for well-trained gamers, but wouldn’t matter for most other people even in games.

C)  You may feel discomfort after changing your monitor with a model that has a larger diagonal and resolution due to low speed or sensitivity of your mouse, low speed of your graphics card or due to the different size of the screen. However, many people read too much of forums and are inclined to blame the input lag as the cause of any discomfort they may feel with their new monitor.

Cutting it short, the problem does exist theoretically, but its practical effect is greatly overstated. An absolute majority of people won’t ever notice a lag of 47 milliseconds, let alone smaller lags, anywhere.