Tuesday, June 4, 2013

Monitors with hybrid dimming of the backlight

Recently we have seen quite a few displays that employ both PWM and voltage regulation in order to dim the backlight. While it might not be an ideal solution, the fact that the PWM doesn't kick in until the brightness is set to 20% or less (in case of the new Eizo EcoView series) and considering that the ~ 75 cd/m² (which corresponds to the above stated brightness setting) should be comfortable enough to use even in case of night-time working, makes these displays worth looking into:
  • EIZO FlexScan EV2736WFS-BK
Although there seems to be some conflicting information regarding whether it's using an IPS (as advertised) or a PLS panel, that shouldn't really matter since the latter one has an almost identical properties to the In-Plane Switching technology. Like the most PLS screens so far, it has a soft coating, which is definitely a plus, because the too aggressive anti-glare filters are known for causing visual discomfort.
  • EIZO FlexScan EV2436W-FS
There are some reports about this monitor having an aggressive AG coating as well as utilizing FRC which can result in color flickering, so my advice would be to avoid it. Of course, it's up to you to decide.

Another monitors that rely on both PWM at the frequency of around 180Hz as well as on a voltage regulation are Samsung S27A850D and Samsung S27B970D. You should be aware that you might still notice flickering if you use any of these two monitors at low brightness settings.

Wednesday, December 26, 2012

Monitors with no PWM

The vast majority of monitors today use PWM (Pulse width modulation) for dimming the backlight. To make things even worse the frequencies at which the backlight is being cycled on and off are quite low - somewhere between 180Hz and 240Hz, which makes it very likely for the flicker to be perceived by humans. As a result various health issues might occur - eyestrain, headaches, dizziness, etc. If you're suffering of any of this, you might want to consider getting a monitor which does not use PWM such as:
  • Dell S2740L
Beware that its coating is a glossy one, making it a highly reflective if used in bright environments. This can cancel any benefits of it being flicker free unless you can use it in a darkened room. Since it's a 27-inch screen and it only has a resolution of 1920 x 1080, it's susceptible to the screen door effect. On the positive side, the text size is bigger out of the box, so that can save you the trouble of adjusting the font sizes in different programs. It also has very low input lag which makes it suitable for gaming.

  • Dell U2713HM
While this one is also in the 27-inch class, it's quite different from the monitor above. First, it has a light AG coating and a resolution of 2560 x 1440. Unfortunately, it has some downsides especially if you're looking for a monitor for color critical work as it covers only about 72% of the Adobe RGB space. Having said that, I really like the fact that there is no FRC used, which means there will be no color flickering. Correct me if I'm wrong, but I believe that would make it the only monitor that is indeed flicker-free as all the rest of the screens in this list incorporate frame rate control.

  • Dell U2713H
Although this screen is quite similar to the HM variant we've already seen but it should be said that it's a lot more suited for design work as it offers support for hardware calibration and it has 97% coverage of the Adobe RGB. The one thing I'm concerned about is the use of Frame Rate Control in order to simulate the 1.07 billion colors because its panel is natively only 8-bit. The reason I'm mentioning this because there is a chance of color flickering, which can undermine the benefit of the absence of PWM.

  • HP ZR2740w
The problem is that there are two revisions of this monitor available with some significant differences between them. The original version didn't have an on-screen display menu and had a quite aggressive anti-glare coating. The newer ones provide remedy for these issues but I don't think there is a way to tell which one you will get.

  • ViewSonic VP2770-LED
Here is yet another 27-inch 1440p display that has a PLS panel. The good news is that it has a light AG coating. But I find the usage of FRC worrisome because it can lead to color flickering meaning despite the lack of PWM, we can't declare this screen to be truly flicker-free.

Another one I'm personally looking very much forward to is BenQ GW2760HS which will be the only monitor with VA panel and no PWM! (as specified by the manufacturer.)