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LCD Motion Blur: Fact and Fiction - Page 2

post #31 of 181
12/3/09 at 5:59pm
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Originally Posted by Beeper View Post

I still see the Victoria Secret Fashion Show on every channel tonight.

Funny, I'm afflicted with that disease too. I think it starts with a cough.

Cheers.
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post #32 of 181
12/3/09 at 7:07pm
I'm really wondering if there are people in this thread confusing judder with motion blur.
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post #33 of 181
12/3/09 at 8:40pm
in most cases what most people perceive as motion blur is not caused by the display but by the source material being watched, this is why these same people believe that 120/240 hz TV's have less blur because if you use their motion enhancers they reduce and sometimes even eliminate most all motion blur

if you want test for blur caused by the LCD panel itself you cannot use films or even most TV shows because they are mostly shot at 24 or 30 fps. this is the source of the blurring

its been long known that 60 fps is optimal for the human eye to perceive smooth motion. the vast majority of TV/movies etc. has been produced at half to less that half of that frame rate.

play video games on your TV and then tell me it blurs, i play PC games on my 60hz 32" sony TV all the time, i've been gaming for over 10 years with use on CRT's extensively, modern LCD panels rarely blur anymore witch is VERY easy to spot when they do because images don't blur but the SMEAR across the screen its very ugly, often certain panels would exhibit this problem with a certain color or color shift.

120/240 hz are not necessary for most people, but if you wish to spend the extra cash it can be nice to have for films mostly but they can enhance the appearance of just about any video type if your into how it makes things look
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post #34 of 181
12/3/09 at 9:37pm
All of this discussion has been very interesting but is missing the point. Allow me to share what I have learned over the years.

CRT-based displays scan from top to bottom and it does not matter if it is interlaced or progressive. After the last line is scanned there is a vertical blanking interval while the scan returns from the bottom to the top. It is during this period that the eye “resets” itself. This period of reset is how the eye perceives the images and generates the illusion of smooth picture transition.

Film content is the same way. There is a dark period from the exposure of the first frame to the next as the shutter closes before the next frame of film is exposed.

Plasma displays scan the entire pixel field from top to bottom to create a “wall charge” on all of the pixels. The sustain circuits then activate to determine the brightness of the pixels and this is continued in sub-fields to determine the brightness of each pixel during the period of one frame. Periods of no light output allow the eye to “reset” similar to CRT and film material.

LCD displays do not have a “dark” period since the backlight source is constant and this is why the eye perceives the blurring phenomenon. The way to counteract this is to insert black frames in between the active video frames to allow the eye to reset and produce the sensation of smooth movement. This is how the frame doubling of 120HZ and frame quadrupling of 240HZ LCD panels reduce the blurring and flickering inherent in LCD displays.
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post #35 of 181
12/3/09 at 9:53pm
Quote:
Originally Posted by display veteran View Post

All of this discussion has been very interesting but is missing the point. Allow me to share what I have learned over the years.

CRT-based displays scan from top to bottom and it does not matter if it is interlaced or progressive. After the last line is scanned there is a vertical blanking interval while the scan returns from the bottom to the top. It is during this period that the eye resets itself. This period of reset is how the eye perceives the images and generates the illusion of smooth picture transition.

Film content is the same way. There is a dark period from the exposure of the first frame to the next as the shutter closes before the next frame of film is exposed.

Plasma displays scan the entire pixel field from top to bottom to create a wall charge on all of the pixels. The sustain circuits then activate to determine the brightness of the pixels and this is continued in sub-fields to determine the brightness of each pixel during the period of one frame. Periods of no light output allow the eye to reset similar to CRT and film material.

LCD displays do not have a dark period since the backlight source is constant and this is why the eye perceives the blurring phenomenon. The way to counteract this is to insert black frames in between the active video frames to allow the eye to reset and produce the sensation of smooth movement. This is how the frame doubling of 120HZ and frame quadrupling of 240HZ LCD panels reduce the blurring and flickering inherent in LCD displays.


great explanation and completely correct

though it still does not change the fact that this problem only exists because of film/video's basic problem of being too low of a frame rate to be perceived as smooth on a sample and hold type display

also blurring is very apparent in movies I've watched in a theater recently, granted i was looking for it but i could see it clearly, it look very much like a movie looks when i watch it on my 60hz TV with motion enhancement turned off (yes some 60hz TV's have motion enhancers that work like the 120hz TV's do, just not as well)
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post #36 of 181
12/3/09 at 10:16pm
Quote:
Originally Posted by display veteran View Post

All of this discussion has been very interesting but is missing the point. Allow me to share what I have learned over the years.

CRT-based displays scan from top to bottom and it does not matter if it is interlaced or progressive. After the last line is scanned there is a vertical blanking interval while the scan returns from the bottom to the top. It is during this period that the eye “resets” itself. This period of reset is how the eye perceives the images and generates the illusion of smooth picture transition.

Film content is the same way. There is a dark period from the exposure of the first frame to the next as the shutter closes before the next frame of film is exposed.

Plasma displays scan the entire pixel field from top to bottom to create a “wall charge” on all of the pixels. The sustain circuits then activate to determine the brightness of the pixels and this is continued in sub-fields to determine the brightness of each pixel during the period of one frame. Periods of no light output allow the eye to “reset” similar to CRT and film material.

LCD displays do not have a “dark” period since the backlight source is constant and this is why the eye perceives the blurring phenomenon. The way to counteract this is to insert black frames in between the active video frames to allow the eye to reset and produce the sensation of smooth movement. This is how the frame doubling of 120HZ and frame quadrupling of 240HZ LCD panels reduce the blurring and flickering inherent in LCD displays.

I think you've missed the point of the study. The study isn't saying Solution A to combat motion blur is better or worse than Solution B. It's saying the solutions aren't necessary because study participants don't see motion blur with moving video even on baseline 60hz LCD panels, let alone 120 or 240hz panels. Period. Your post is premised on the assumption that motion blur is visible with 60hz panels (and you need a specific type of technical implementation to combat it) but the study seeks to refute that foundational assumption: when it comes to live video, motion blur is not visible on currently sold 60hz LCD panels. I don't question your explanation but what aspect of LCD technology makes it more susceptible to motion blur than other techs is irrelevant to the study's conclusions.

BTW, this study was first published and publicized back in October by cnet's television reviewer. Extremetech, a sister publication, seems to have recycled it. Here's cnet's report about it:

http://news.cnet.com/8301-17938_105-10374343-1.html
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post #37 of 181
12/3/09 at 10:30pm
This thread has 2 links showing what real LCD motion blur looks like on an LCD, any good LCD TV panel will not do this regardless of its refresh rate, also take note that this is a 120hz TV!

cheap panels make for real motion blur not the refresh rate
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post #38 of 181
12/3/09 at 10:58pm
The best remedy is the backlight strobe.


My bro have a 120hz Sharp, me I use both Panasonic LZ800 & Panasonic G15(plasma 1080 lines of motion resolution). I still have also a old CRT monitor.

120 & 240hz is the best option for accurate viewing for movies for 24hz content. I'm not really into that interpolation technique since it's not an ideal method since it trick out the real content of the media which cannot be actually redone & may work very bad for 60 or 30fps content. Those make the TV display being delayed which make the panel being unusable for games.

I usually do the motion test at http://www.lagom.nl/lcd-test/response_time.php with the 8 bar moving test. I tested with the Plasma, the back light strobe, CRT & 120hz. The best indeed is the CRT & plasma. After the backlight strobe come very close to it, but 120hz is less good.

LCD without any help & even the 2ms panel have issue with motion blur.

Sure some say they don't have too much problem with it, but try to spot stuff when there's more than 30 object on screen & you will noticed it very bad.
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post #39 of 181
12/4/09 at 1:08am
He lost me right here;

Quote:


such as the upcoming generations of 3D displays."

Let's focus on 3D displays? Really? Sorry, but 3D displays is going to be more gimmicky and marketing hype than 240Hz is. Nobody is going to buy those displays in masses for the one or two 3D movies that come out a year. Really? That's what he's excited about, but he totally dismisses 120Hz and says blurring is a thing of the past.
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post #40 of 181
12/4/09 at 2:22am
their is a difference in b/w 60hz and 120hz.yes it does reduce blur.240hz is still better then 60hz/120hz+backlight scanning.

sharps UV2A has a faster response time which reduces blur without the need of 120 and 240hz frame interpolation.since the response time of UV2A is in micro seconds compared existing lcd tech which is still in milli seconds.
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post #41 of 181
12/4/09 at 6:29am
Quote:
Originally Posted by display veteran View Post

All of this discussion has been very interesting but is missing the point. Allow me to share what I have learned over the years.

LCD displays do not have a “dark” period since the backlight source is constant and this is why the eye perceives the blurring phenomenon.....

Something new can be learned every day. Various LCD displays have been available with "dark" periods.

http://en.wikipedia.org/wiki/HDTV_blur <<>> http://www.hdtvmagazine.com/articles..._your_eyes.php

Strobing backlight

* Philips created Aptura also known as ClearLCD to strobe the backlight in order to reduce the sample time and thus the retinal blurring due to sample-and-hold.

* Samsung developed "LED Motion Plus" strobed backlighting and is available on the "Samsung 81 Series" LCD screens as of August 2007.

* BenQ developed SPD (Simulated Pulse Drive) also more commonly known as "black frame insertion" and they claim that their images are as stable and clear as CRT's. This is conceptually similar to a strobing backlight.

Toshiba and LG are currently selling LCDs with back light scanning technology.
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post #42 of 181
12/4/09 at 8:14am
Quote:
Originally Posted by Beeper View Post

Something new can be learned every day. Various LCD displays have been available with "dark" periods.

Strobing backlight

* Philips created Aptura also known as ClearLCD to strobe the backlight in order to reduce the sample time and thus the retinal blurring due to sample-and-hold.

* Samsung developed "LED Motion Plus" strobed backlighting and is available on the "Samsung 81 Series" LCD screens as of August 2007.

* BenQ developed SPD (Simulated Pulse Drive) also more commonly known as "black frame insertion" and they claim that their images are as stable and clear as CRT's. This is conceptually similar to a strobing backlight.

Toshiba and LG are currently selling LCDs with back light scanning technology.

Add to this the Sony XBR8 line (called X4500 in other countries) - available since 2008 - which offers backlight scanning by setting Motionflow on "Clear".
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post #43 of 181
12/4/09 at 9:39am
Quote:
Originally Posted by HD_Lantern View Post

Based on my eyes, I see blurring on a LCD even with a high quality blu-ray source. Try watching say, the Fast and Furious movies on a 50+ inch LCD versus a similar sized Plasma. I'd think that most people will notice blurring on the LCD.

I am not trying to be inciteful here but, really? You attribute this to the display technology and not the antique long aperture 24fps process that movies are shot in? Seriously there are people that are arguing that 60/120/240hz displays are the cause of less than ideal display for fast action 24fps movie content?
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post #44 of 181
12/4/09 at 10:15am
Quote:
Originally Posted by user4avsforum View Post

I am not trying to be inciteful here but, really? You attribute this to the display technology and not the antique long aperture 24fps process that movies are shot in? Seriously there are people that are arguing that 60/120/240hz displays are the cause of less than ideal display for fast action 24fps movie content?

I see about as much blur on plasmas as I do on new LCDs. I always attributed it to the 24fps. And I wouldn't even call it blur. But, something more comparable to judder. I don't really notice anything when watching a TV program. Just movies. Which is why I blame 24fps.
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post #45 of 181
12/4/09 at 11:05am
Motion blur and Judder are two different potential problem areas.

And there are two kinds of Judder.
First there is 24fps filming judder caused by the fact that 24fps is just not fast enough to catch all motion smoothly. It is most apparent slow panning scenes.
Secondly there is 3:2 pull down judder caused when 24fps content is converted to 60 fps by displaying 1/2 of the frames 3 times and the 1/2 of the frames 2 times.
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post #46 of 181
12/4/09 at 11:07am
Quote:
Originally Posted by MrEastSide View Post

I see about as much blur on plasmas as I do on new LCDs. I always attributed it to the 24fps. And I wouldn't even call it blur. But, something more comparable to judder. I don't really notice anything when watching a TV program. Just movies. Which is why I blame 24fps.

Turn on ESPN2 and watch the ticker and watch stationary text and then when it starts to scroll. That is a 60p source and the easiest for most people to try and see it.
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post #47 of 181
12/4/09 at 11:42am
To those that think that blur is in the source, go play a 60fps video game. (Ninja Gaiden Sigma on the PS3 is my personal favorite blur test, as there is ZERO built in blur) On an LCD that is 60hz, there will be massive out of focus blur, on a 120hz LCD with the blur reduction cranked, the blur will be less visible, and a similar decrease in blur occurs with 240hz LCDs. Plasma sets have little to no blur with the same content and looks basically the same in motion as it does in a still image with a 60fps source. This is caused by the sample and hold nature of LCD and it is the reason that all these added 120 and 240 hz modes are needed in LCDs.

And older article, but still 100% relevant
http://hometheatermag.com/gearworks/707gear/
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post #48 of 181
12/4/09 at 11:52am
Quote:
Originally Posted by PENDRAG0ON View Post

To those that think that blur is in the source, go play a 60fps video game. (Ninja Gaiden Sigma on the PS3 is my personal favorite blur test, as there is ZERO built in blur) On an LCD that is 60hz, there will be massive out of focus blur, on a 120hz LCD with the blur reduction cranked, the blur will be less visible, and a similar decrease in blur occurs with 240hz LCDs. Plasma sets have little to no blur with the same content and looks basically the same in motion as it does in a still image with a 60fps source. This is caused by the sample and hold nature of LCD and it is the reason that all these added 120 and 240 hz modes are needed in LCDs.

And older article, but still 100% relevant
http://hometheatermag.com/gearworks/707gear/

That is a much better article in that in talks about the problem of sample-and-hold. The article posted at the beginning of this thread doesn't even address it. Blur caused by slower pixel response time is only part of the problem.
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post #49 of 181
12/4/09 at 1:02pm
Quote:
Originally Posted by PENDRAG0ON View Post

To those that think that blur is in the source, go play a 60fps video game. (Ninja Gaiden Sigma on the PS3 is my personal favorite blur test, as there is ZERO built in blur) On an LCD that is 60hz, there will be massive out of focus blur, on a 120hz LCD with the blur reduction cranked, the blur will be less visible, and a similar decrease in blur occurs with 240hz LCDs. Plasma sets have little to no blur with the same content and looks basically the same in motion as it does in a still image with a 60fps source. This is caused by the sample and hold nature of LCD and it is the reason that all these added 120 and 240 hz modes are needed in LCDs.

And older article, but still 100% relevant
http://hometheatermag.com/gearworks/707gear/

Thank you for posting this article. While it only touches on full 240 Hz blur reduction technology it addresses the basic blur problem with LCDs which is the sample and hold nature of LCDs.

Some of us like to read the credits from a movie or TV show, not to mention watching sports and action movies.
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post #50 of 181
12/4/09 at 1:48pm
Quote:
Originally Posted by spyboy View Post

Some of us like to read the credits from a movie or TV show

By your logic text displayed on say a website would blur on an lcd monitor if one were to simply scroll (since you mentioned wanting to read credits as they scrolled by). However, the majority of people use lcd monitors for their pcs, and scroll through text documents and websites everyday without observing blurring. Why would you bother to try to make a connection between moving credits and motion blur since it's so obviously wrong?
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post #51 of 181
12/4/09 at 2:39pm
Quote:
Originally Posted by mahlerfan999 View Post

By your logic text displayed on say a website would blur on an lcd monitor if one were to simply scroll (since you mentioned wanting to read credits as they scrolled by). However, the majority of people use lcd monitors for their pcs, and scroll through text documents and websites everyday without observing blurring. Why would you bother to try to make a connection between moving credits and motion blur since it's so obviously wrong?

An example has been made of watching a stock ticker (for motion blur). IMHO, screen credits, which are often speeded up considerably by channels such as Lifetime Movie Network, and others, run the credits so fast, I can barely make them out.

Your use of scrolling on a PC isn't the same as speeded up credits on a TV.

Thanks for your contribution to this thread.
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post #52 of 181
12/4/09 at 2:40pm
Another aspect to pile on top of various other causes of perceived blur in this discussion, is that it is natural for the image of a fast moving
object to be perceived as blurred (dependent on velocity and distance) when it is interpreted by the human brain (to varying degree).

Those that claim, "I don't see any blur on a plasma", must not be viewing an object that is moving fast enough.

Try the following. (No intoxication required.)

Place your hand stationary in front of your face with your fingers spread apart. A nice clear image.

Now move your hand back and forth real fast. The image of your fingers should have appeared blurry.

The image interpreted by your brain was naturally blurred by movement.
A fast moving image on any type of display should have that same effect.

Somewhat related article. http://www.100fps.com/how_many_frame...humans_see.htm
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post #53 of 181
12/4/09 at 5:23pm
Agreed, at some point all display technologies will show blur because it is in the source. But I think for the most part we have to compare to the older technology, CRT, and that it should be at least that good. LCD is not.
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post #54 of 181
12/4/09 at 6:32pm
Quote:
Originally Posted by primetimeguy View Post

Agreed, at some point all display technologies will show blur because it is in the source. But I think for the most part we have to compare to the older technology, CRT, and that it should be at least that good. LCD is not.

nothing compares to CRT and nothing will because it uses beams of light shot at phosphors to to display images at the speed of light, this and the fact that their image is constantly refreshed by design means you get a very good motion image under all circumstances, when my CRT RPTV is tuned correctly i love its 1080i picture more than anything if your sitting in its viewing area, when it comes to sharpness and detail of a still image on a screen LCD is king nothing compares to it in this respect

DLP is prob. the only thing that can compare to CRT display types but it has the same viewing angle and blurriness problems suffered by CRT RPTV's oh and anyone will tell you if you can find one of them sony XBR HD CRT direct view TV's pick it up and you will be blown away by a 1080i CRT TV's image compared to current tech in most situations esp movies

LCD has the problem of using a back light that is always on or flickers at a certain rate (scanning backlight) to simulate a CRT picture but the real problem is the use of liquid crystals that must be rotated various degrees to control the flow of light, the LCD itself has absolutely no refresh rate itself what it does have is a response time witch will vary depending on wither the manufacture decided to measure it the right way (black-white-black response) or the wrong way (gray to gray response) witch many do this and its cheating plain and simple.
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post #55 of 181
12/4/09 at 7:12pm
Quote:
Originally Posted by frito View Post

nothing compares to CRT and nothing will because it uses beams of light shot at phosphors to to display images at the speed of light, this and the fact that their image is constantly refreshed by design means you get a very good motion image under all circumstances, when my CRT RPTV is tuned correctly i love its 1080i picture more than anything if your sitting in its viewing area, when it comes to sharpness and detail of a still image on a screen LCD is king nothing compares to it in this respect.

CRT displays images at the speed of light? They display images relative to their horizontal and vertical frequency scan rates! Does this mean the backlight behind the LCD crystals is not travelling at the speed of light?
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post #56 of 181
12/4/09 at 7:26pm
Quote:
Originally Posted by peterlee View Post

I think you've missed the point of the study. The study isn't saying Solution A to combat motion blur is better or worse than Solution B. It's saying the solutions aren't necessary because study participants don't see motion blur with moving video even on baseline 60hz LCD panels, let alone 120 or 240hz panels. Period. Your post is premised on the assumption that motion blur is visible with 60hz panels (and you need a specific type of technical implementation to combat it) but the study seeks to refute that foundational assumption: when it comes to live video, motion blur is not visible on currently sold 60hz LCD panels. I don't question your explanation but what aspect of LCD technology makes it more susceptible to motion blur than other techs is irrelevant to the study's conclusions.

Let's say you take a group of 100 people and have them watch an LCD display with moving video. Let us make that a display that has 3 defective pixels on it. 99 out of the 100 will not notice the defective pixels. Does that make the defective pixels not there? Of course not. This study is flawed.

The biggest complaint received for refresh issues manifests itself as "eye strain". The customer does not relate the flickering to the eye strain and/or headaches. This is more common with display that is viewed too closely (too large for the living area). The higher frame-rate panels reduce or eliminate this symptom.
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post #57 of 181
12/4/09 at 7:49pm
Quote:
Originally Posted by display veteran View Post

Let's say you take a group of 100 people and have them watch an LCD display with moving video. Let us make that a display that has 3 defective pixels on it. 99 out of the 100 will not notice the defective pixels. Does that make the defective pixels not there? Of course not. This study is flawed.

That doesn't follow at all that the study is flawed. Your analogy does not sink it. In your example a study shows that people don't notice 3 defective pixels out of 2 million. Yes the defective pixels are there. Did the study show otherwise? No. Did the study show that it's not an issue? Yes. That pretty much makes the test a success.

It's the same thing with the motion blur study. It's not designed to study the existence of motion blur, it's designed to study to what degree do we perceive it. Why does this make it flawed? It doesn't. Just because something exists doesn't mean that we will perceive it.

An analogy that would be more appropriate would be the high frequency range used in sacds. Nobody would deny that it's possible to have audio information over such a large range. But a question that studies can and did answer "do we perceive that extra frequency range?" is more pertinent.

Quote:


The biggest complaint received for refresh issues manifests itself as "eye strain". The customer does not relate the flickering to the eye strain and/or headaches. This is more common with display that is viewed too closely (too large for the living area). The higher frame-rate panels reduce or eliminate this symptom.

Well that's actually interesting. I would like to see tests on that because I find it more likely to be that such eye strain and headaches would come from using torch mode rather than refresh rate.
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post #58 of 181
12/4/09 at 9:26pm
Quote:
Originally Posted by display veteran View Post

CRT displays images at the speed of light? They display images relative to their horizontal and vertical frequency scan rates! Does this mean the backlight behind the LCD crystals is not travelling at the speed of light?

yeah you got me there, you know what i'm saying though CRT always has been the best thing for speed and motion processing just by how it works
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post #59 of 181
12/5/09 at 8:07am
Thread Starter 
Great replies guys, very informative. I posted the article to spur discussion on the topic and that worked. I myself still believe motion blur is a concern but it did put my mind as ease a bit about having to spend a lot more on a 240hz TV.

Keep up the great replies.
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post #60 of 181
12/5/09 at 9:38am
Quote:
Originally Posted by TheOnion View Post

Great replies guys, very informative. I posted the article to spur discussion on the topic and that worked. I myself still believe motion blur is a concern but it did put my mind as ease a bit about having to spend a lot more on a 240hz TV.

Keep up the great replies.

If you accept the study as a whole, there is no point in buying other than a 60 hz panel. There is no middle ground according to this study. 120 Hz won't get you any less motion blur than 60 Hz.

If you believe that people can see motion blur, then, the true 240 hz sets are the way to go, if you are interested in the least motion blur for sports, and action movies.

There are many questionable issues in the "study", but it is not worth much more time right now to point them out. But I will leave you with these two.

"Our most important and significant result is that the LCD manufacturers have finally beaten the motion blur problem." Yeah, manufacturers are now just running a scam on the public in regards to motion blur.

The omission of discussion of sample and hold is conspicuous in its absence.
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