Does lightboost/ULMB make a big diff w/ fast response times

[Falkentyne]

Thanks, Chief.

All I really want is for overdrive and ghosting to become a thing of the past.
We can put a rover on Mars but we can't make a panel with NO ghosting and NO overdrive?

Is there a way to do this with normal refresh rates with current tech?

[masterotaku]

Thanks, Chief.

Damn, I was going to correct you about those wrong miliseconds, but I was at class. Chief beat me .

All I really want is for overdrive and ghosting to become a thing of the past.
We can put a rover on Mars but we can't make a panel with NO ghosting and NO overdrive?

Let's wait for OLED at 4k with strobing, perfect colors and contrast.


That displayport 1.3 better be released soon (it will allow the bandwidth necessary for 4k at 120Hz).

[Chief Blur Buster]

Is there a way to do this with normal refresh rates with current tech?

Extremely challenging. We need blue-phase LCDs (GtG in microseconds) or rolling-scan OLEDs.

With the OLED manufacturing rampup especially for 50"-55" 4K OLEDs that looks soon to fall below $1K per panel within a few years, hopefully 24"-27" 1080p OLED gaming monitors isn't too far into the future (2-3 years tops, hopefully) as you now only need to cut up an 4K OLED TV panel into quadrants. Hopefully we'll get our "Blur Busters Dream" OLED gaming monitor before the 2020s, and these won't have ghosting, and would hopefully have an adjustable persistence (adjustable rolling scan window).

[RealNC]

We can put a rover on Mars but we can't make a panel with NO ghosting and NO overdrive?

Well, there are such panels for the scientific community. They cost around the same as an expensive car...

[masterotaku]

We can put a rover on Mars but we can't make a panel with NO ghosting and NO overdrive?

Well, there are such panels for the scientific community. They cost around the same as an expensive car...

Wrong quote (Falkentyne said that).

I'm wondering why overdrive artifacts are the same at less Hz in the same monitor. If the transition can't be completed in 7 or 8 ms, that's already way more than the advertised 1ms of response time, but why are those artifacts still happening at for example 60Hz? The overshoot of BenQ AMA should regain normal levels and perfect image before the frame is finished at 60Hz, and changing the strobe phase should reflect that, not only crosstalk, I think.

[Chief Blur Buster]

Overdrive issue is NOT a response time limtation, but a precision limitation.

Overdrive is ESSENTIALLY guesswork. It calculated what voltage the LCD pixels needs to accelerate the pixel to the new color.

Think of it this way: Trying to accelerate a car blindly to an exact speed, as quickly as possible. Pressing the gas pedal blindfolded (flooring it) to try to reach an exact speed, without being able to read a speedometer. Guess how long you need to FLOOR the gas pedal to accelerate quickly to exactly "X" miles per hour, such as exactly 35 miles per hour, without being able to see the speedometer or look out of the windshield. A computer could do that, and get pretty close by creating a lookup table of how many millisecond it needs to floor the gas to get to each mph, and then stop flooring (letting it coast), to accelerate to an exact speed as quickly as possible, blindly.

Unfortunately, it is not even that simple either.

Cold LCDs take longer to do GtG, so you need more voltage to do the same overdrive at the same speed. But most LCD do nit have a thermometer calculation factored into its overdrive, which is why sometimes overdrive looks different in a very cold room than in a hot room. And manufacturing can create LCDs that are a few microseconds faster or slower, they are not all perfectly as exactly the same, often because of a few extra or fewer liquid crystal molecules in the pixels, than the last manufacturing run, affecting the response of the pixels by an infinestimally tiny amount but enough to throw off the accuracy of the overdrive guesswork.

Overdrive lookup tables built into your monitor, is usually pre-calculated at room temperature. Different LCDs may respond microseconds slower or microseconds faster, so the lookup table may not be exact.

It like getting 34mph or 36mph when you meant to floor the gas pedal briefly to reach exactly 35mph as quickly as possible and releasing the gas pedal based on known statistics (without being able to see a speedometer or looking out of the window) - overdrive overshoot may make a pixel slightly too dim or too bright (ghosting and corona the result).

This happens regardless of how slow or fast the pixels are. The LCD pixel gets a surge of exact voltage, once a refresh, and if it is the wrong voltage for the wrong time period, or the LCD is slightly different from the LCD that was used to generate the overdrive lookup table (which voltage to use for going from a specific color to another color, ala grey-to-grey, as quickly as possible with maximum accuracy).

Overdrive is a game of guesswork to massively speed up pixel transitions but the pixels will not always land at the exact desired color because the chosen overdrive voltage is a few microvolts off... The circuits in the display cant "see" what the liquid crystal molecules are doing or aligned (much like, you cannot read a speedometer in the "car acceleration" guesswork).

In the car example; there is inconsistency too. The car may have too much oil or little oil, the tires may be under high or low pressure, the engine is warmed up or not, and the engine might not be in best condition/tune up. So the exact same exact amount of flooring gas pedal (e.g. floor gas pedal doe exactly 3.75 seconds) will accelerate a car to a slightly different speed than doing the same in a different car even of exact same model. Overdrive can get really good, artifacts below visual perception in the best case scenario, but it can never be perfect.

I tried to explain, the best I can, with the car blind-driving metaphor. Hope that makes sense!

[Falkentyne]

So THIS explains why lightboost looks like crap on my VG248QE after I had the panel switched off all night?
(it's bad enough that the gamma changes on that thing from like 2.4 at 60hz to 2.17 at 144hz)
My XL2720Z keeps the exact same gamma at 60hz and 144hz. Can't say I'm unhappy about that. (glad I bought a 27" 1080p panel).

[Chief Blur Buster]

Bingo!

If you see more LightBoost ghosting on a cold panel, that's why. Cold panels often ghost more, and the overdrive tables are often calibrated based on an average factory run panel, at room temperature, and fully warmed-up on the desktop. Half an hour powered up, in a room about 68F / 20C, will often bring the point of least ghosting on most panels. It makes a dramatic difference on EIZO FG2421, though less so (though it's there to an extent) on LightBoost panels. Some panels are more temperature sensitive than others, even between different LightBoost panels and panel sizes.