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Discussion Starter #1
I serched the forum about screen door effects for the Samsung DLPs and didn't find anything but, last night watching a Sex and the City DVD in progressive mode I seemed to have noticed the screen effect on occasion. It occured right after a cut in a scene; I've heard of this problem with LCD rear projectors but not on DLP. Am I crazy or what; have any onther Samsung DLP owners experienced this? I have the HLN 5065W by the way, JVC 50K DVD using component 1.


Thanks -- Steve
 

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I think you might be talking about pixelation or blocking where the image seems to be a bunch of blocks then they breakdown into the correct image.


Screen Door Effect (SDE) looks just like you are standing at a screen door looking through it outside. You can see outside fine but the screens fine mesh is still visible. This is exactly what SDE looks like on RPTVs, But it is there all the time. More noticeable on light colored images than dark.


You don't hear much on SDE with DLPs because it has a pretty small pixel grid. LCD shows it just a bit more, plasma may be even more than LCD and LCoS has the least amount of SDE of the fixed pixel displays.


So the blocking does happen and SDE on DLP is possible but you would have to be sitting very close to the screen to see it. I hope that helps?
 

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"You don't hear much on SDE with DLPs because it has a pretty small pixel grid."


Go to the projection areas for plenty on DLP SDE. :)


One thing about DLP is that the pixel edges are super sharp right now, making the SDE very apparent.


The new HD3 and xHD3 somehow "blur" the pixel edges and mitigate this. I suspect the net result will be good.
 

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Quote:
Originally posted by rogo
One thing about DLP is that the pixel edges are super sharp right now, making the SDE very apparent.
On an RPTV at least, SDE on my DLP set is completely non-existant from more than a few feet away. I could easily see it on the GWIII and Panasonic LCD's I had from 9' away.


I don't know how you can say SDE is "very apparent" on a DLP set, unless you're talking about a front projected image of a very large size. On a DLP RPTV, SDE is a non-issue. SDE is much more apparent on LCD RPTV sets, if you're looking for that kind of thing...


Of course, that's just my opinion, I could be wrong.
 

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SDE is not a problem on DLP RPTV's.


The best way to test for SDE is to have a light solid color (like tan, grey, or white) as the full screen image.
 

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This thread brings up an interesting question. All Samsung DLP's have the same number of pixels no matter what the screen size, right? Does that mean as the screen size increase so does the size of each pixel.? That normally would not be a problem since you figure that the larger screen size the further the person is sitting from the screen. We don't know what screen size Toogos' has but if he had a 56 or 61 and sat closer than 8 feet, could he have seen a SDE?


I would be interested in the opinions since that is something to consider when selecting a screen size closer than the recommended viewing distance. Of course, I can be all wet.
 

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This sounds crazy to me, I've had my Samsung DLP for months now and never have seen the "Screen door effect" or "rainbows", but when looking at Plasma TVs I see nothing but SDE's.... I am absolutely blown away how great the pic has become after the break in period on my Sammy, I have digital cable I am looking into going HD via either through our cable company or look into Voom..
 

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Quote:
Originally posted by jtirak
This thread brings up an interesting question. All Samsung DLP's have the same number of pixels no matter what the screen size, right? Does that mean as the screen size increase so does the size of each pixel.? That normally would not be a problem since you figure that the larger screen size the further the person is sitting from the screen. We don't know what screen size Toogos' has but if he had a 56 or 61 and sat closer than 8 feet, could he have seen a SDE?


I would be interested in the opinions since that is something to consider when selecting a screen size closer than the recommended viewing distance. Of course, I can be all wet.
You are correct. The SDE really bothers me. I do notice it on my 617 but it is very faint at over 10' viewing distance. Yesterday, I saw a couple of LG LCDs that had it really bad. I would not be able to buy that set.
 

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I noticed it on a Samsung DLP in a store the other day from about 10' back on very bright scenes. It looks just like my Sony 50" GWII - so it appears to be present to some degree in both technologies.


After 10 months of owning this set, I really don't see it much anymore - after a while I think that your eye compensates and you tend to look 'through' it without noticing it.


That's my theory anyway.
 

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This discussion is really about DLP, if I read the original post right. Therefore, explaining that SDE is worse on LCD is about as useful as bringing up good recipes for eggplant.


Of course, SDE is less bad on DLP than LCD, but it's totally there on DLP. I'm glad most people don't see it at normal viewing distance. On the new HD3, it's practically impossible to see in the traditional sense with your nose at the screen due to whatever gimmick TI is succesfully employing with HD3.


"SDE is not a problem on DLP RPTV's" is an opinion, not a fact.


Some people like to sit real close and might be better served, WRT SDE (ugly acronym alert) by, say, LCOS, which has the finest grid of them all and lacks sharp-edged pixels. You really need to be up close to an LCOS display like the Philips to find the pixel grid at all.


Mark
 

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Discussion Starter #12
After watching a movie last night on my 5065, I saw no apparent SDE; perhaps it has somewhat to do with the source material. I hope this is it because the SDE from the Sex in the City DVD was very bothersome. The set is 50" and I sit about 8 feet away. Although when we play with the PS2 we are generally much closer and I have not seen SDE, but then again the action in the racing games is pretty intense so we may not be aware of them if they are happening.


I do not see rainbows as well, however, my wife sees them all the time, but see has never mentioned SDE.


Thanks for all the info, great forum.


Steve
 

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Quote:
Originally posted by rogo
"SDE is not a problem on DLP RPTV's" is an opinion, not a fact.
Agreed. Just like everything else posted on this forum, my statement was my opinion. However, I will stand by my opinion that on a DLP set viewed at a reasonable viewing distance, SDE is a non-issue.


If you've got someone sitting 5 feet away from a 61" set, then yes they'll probably see some SDE, but at a reasonable viewing distance it's nothing to worry about.
 

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Quote:
Originally posted by rogo
This discussion is really about DLP, if I read the original post right. Therefore, explaining that SDE is worse on LCD is about as useful as bringing up good recipes for eggplant.


Of course, SDE is less bad on DLP than LCD, but it's totally there on DLP. I'm glad most people don't see it at normal viewing distance. On the new HD3, it's practically impossible to see in the traditional sense with your nose at the screen due to whatever gimmick TI is succesfully employing with HD3.


"SDE is not a problem on DLP RPTV's" is an opinion, not a fact.


Some people like to sit real close and might be better served, WRT SDE (ugly acronym alert) by, say, LCOS, which has the finest grid of them all and lacks sharp-edged pixels. You really need to be up close to an LCOS display like the Philips to find the pixel grid at all.


Mark
What about SDE on sets with the new HD2+ chips? Do you find the improvement as good as the HD3?
 

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jtirak,


Number of pixels from one DLP to another is the same (720p is the same from 42" to 61") but the number of mirrors per chip increases based on the size of the screen. The 50 has somewhere around 1m mirrors vrs. the 61 has 1.3m. I guess this is to compensate for the larger screen.


Mongo
 

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Quote:
Originally posted by Imongox
jtirak,


Number of pixels from one DLP to another is the same (720p is the same from 42" to 61") but the number of mirrors per chip increases based on the size of the screen. The 50 has somewhere around 1m mirrors vrs. the 61 has 1.3m. I guess this is to compensate for the larger screen.


Mongo
Thanks Mongo, That is fascinating information I have never heard before. So that each TI chip is different based on the screen size and not the projection throw itself. That adds to my knowledge and appreciation for what TI put into it.
 

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Quote:
Originally posted by toogos
I last night watching a Sex and the City DVD in progressive mode

Thanks -- Steve
I just noticed in your original post that you said the DVD was set for progressive mode. Most of the posts I have seen on here said to leave the progressive mode off on the DVD and let the Sammy do it since it has a better scaler and the results are better. Not seen this myself yet but it seems to be a common practice. Perhaps this prescaling by the DVD player may have introduced some of this SDE. Anyone who had done this have any comments? I am interested too since I am waiting delivery of my new 43.
 

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Quote:
Originally posted by Imongox
jtirak,


Number of pixels from one DLP to another is the same (720p is the same from 42" to 61") but the number of mirrors per chip increases based on the size of the screen. The 50 has somewhere around 1m mirrors vrs. the 61 has 1.3m. I guess this is to compensate for the larger screen.


Mongo
You need to substantiate your fascinating information.


I've always thought that one mirror equaled one pixel.


A resolution of 1280x720 requires 921,600 pixels. How would one make use of more than one mirror per pixel? In your example one would have to use one mirror plus .3 of a second mirror for each pixel for the HLN617. Amazing.


It seems to me that some mirrors would have to service three pixels at the same time. The death of a mirror would have a very different meaning for a HLN617 than for a HLN437.


Maybe there are extra mirrors (over 921,600) for adjustment reasons but never get used for the 720p image. If so, that wouldn't require more mirrors as the screen size increased.


Would DLP front projector owners have to specify the screen size they were planing when they buy their 720p projectors?
 

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Quote:
Originally posted by Imongox
Number of pixels from one DLP to another is the same (720p is the same from 42" to 61") but the number of mirrors per chip increases based on the size of the screen. The 50 has somewhere around 1m mirrors vrs. the 61 has 1.3m. I guess this is to compensate for the larger screen.
I don't think so.


TI's HD2 DMD chip is a 1280x720 resolution chip. It is exactly the same from the 43" all the way up to the 61" screen.. There are exactly 921,600 mirrors on the surface of the chip regardless of screen size - and exactly 921,600 pixels on the screen as well. The pixels simply get larger as you go up in screen size.
 

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Quote:
Originally posted by Barrybud
I think you might be talking about pixelation or blocking where the image seems to be a bunch of blocks then they breakdown into the correct image.


Screen Door Effect (SDE) looks just like you are standing at a screen door looking through it outside. You can see outside fine but the screens fine mesh is still visible. This is exactly what SDE looks like on RPTVs, But it is there all the time. More noticeable on light colored images than dark.


You don't hear much on SDE with DLPs because it has a pretty small pixel grid. LCD shows it just a bit more, plasma may be even more than LCD and LCoS has the least amount of SDE of the fixed pixel displays.


So the blocking does happen and SDE on DLP is possible but you would have to be sitting very close to the screen to see it. I hope that helps?
When it comes to SDE , plasma's are the worst.
 
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