Eizo FDF2405W: 120Hz VA monitor with 240Hz and 5000:1 contrast

Posted Aug 31, 2013 by

Eizo announced the DuraVision FDF2405W, a 120Hz monitor that’s not a TN panel.

Featuring a VA panel with a 5000:1 contrast ratio, 178 degree viewing angle, a 240Hz low-latency strobe backlight mode, and 3D glasses capability. Specs never simultaneously achieved in a single flat panel computer monitor.

EDIT #1: pcmonitors.info says this monitor uses a strobe backlight similiar to LightBoost.
EDIT #2: Confirmed, page 15 of the manual mentions backlight strobing. No interpolation.
UPDATE: Eizo has released the gaming version of this monitor, the Foris FG2421!

About Mark Rejhon

Also known as Chief Blur Buster. Founder of Blur Busters. Inventor of TestUFO. Read more about him on the About Mark page.

2 Comments For “Eizo FDF2405W: 120Hz VA monitor with 240Hz and 5000:1 contrast”

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Mark Rejhon
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Mark Rejhon

From PCmonitors.info posted on Overclock.net:

Regarding the strobing backlight and more specifically the ‘blur reduction’ mode, the user manual has some information (page 15).
http://www.eizo.com/global/support/db/files/manuals/03V24694A1/Manual-EN.pdf
It isn’t a technique I’m entirely familiar with so not sure how it will work in practice (limited experience with TVs doing that sort of thing as well), but in theory it should work well.

Aha, that definitely answers my question! I am familiar with this technique used. Quoting from Eizo’s manual:

From Eizo FDF2405W Manual, Page 15
Reducing motion blur “Blur Reduction”
Motion blur occurs when the eye recognizes liquid crystal transitions which comes from changing screens
(frames).
When “Blur Reduction” is set to “On”, the backlight flickers in sync with liquid crystal transition*1 so the change cannot be seen, thereby achieving clear images with less blur. (Default setting:

On) *1 This monitor converts 120 Hz input signals into 240 Hz within the panel, and doubles the refresh rate to draw two images per frame. By applying a voltage higher than the input signal to speed up response (overdrive) for the first image, and then drawing the second image with the original input signal, the liquid crystals are stabilized. The “Blur Reduction” function turns on the backlight only for the stable duration of the second image, and off for other durations

I am familiar with the science behind this.
A double-pass refresh with a strobe backlight on only every other refresh. So it’s not using interpolation after all! So it’s not going to have any interpolation-related input lag. This is good news.

This makes total sense. Refresh a heavily-overdriven image during the first pass while backlight is off, and then refresh a normally-driven image to give the LCD pixels a final push to their correct values, and then finally strobe the backlight (ala LightBoost). I wonder how long the strobe lengths are. Is this a 4.16ms strobe length (worse than LightBoost), or a very short LightBoost-style strobe length (1ms)?

The brightness of 350cd in strobe mode, versus 450cd in non-strobe mode, suggests the strobe length is very long, or LED boost current is very, very high. Either a slightly LED-boost-currented 4ms strobe, or a massively LED-boost-currented 2ms strobe. I’m hoping it’s the latter. 350cd in strobe mode is impressive. This would mean this monitor won’t have as little motion blur as a LightBoost monitor, but you would have potentially far less artifacts than LightBoost because of the creative double-pass LCD refresh to prep the panel to a very clear image before strobing once on the second refresh. I am familiar that a two-pass refresh eliminate a LOT of VA artifact problems, when you can turn off the backlight during VA transitions.

If I can attempt to get my hands on this monitor, or can visit someone who has a demo, I’ll run oscilloscope tests & a high speed camera on it, much like I did for this LightBoost high speed youtube.

CONFIRMED (by this description): Eizo is using a strobe backlight.
CONFIRMED (by this description): The “240Hz” mode in this monitor does not use interpolation.

In pure-strobe backlight monitors, during framerate-matching-Hz motion, motion blur is reliably dictated directly by the strobe length of a strobe backlight. The human eye is only seeing 120Hz during the 240Hz mode, but you’re getting the motion clarity of 240fps@240Hz. (But hopefully better — as I’ve already said, LightBoost produces the motion clarity of 400fps@400Hz at LB=100% 1/400sec strobe lengty, and the motion clarity of 700fps@700Hz at LB=10% 1/700sec strobe length)

This is better than I expected. May actually be a usable gaming monitor. Possibly a bit more input lag, maybe slightly worse than LightBoost, but better than Samsung 3D mode. Still playable for many. Hopefully Eizo has a plan to release a gaming-monitor version of this monitor; Blur Busters will be scrambling hard to get any non-TN strobed desktop monitor.

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