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Why is DLP so unpopular?

Discussion in 'Displays' started by DaveF, Nov 9, 2008.

  1. DaveF

    DaveF Moderator
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    Really? Compared to what? How so?

    The failure modes of a micro-mirror array driven by a complex processor illuminated by a high intensity light source and colored by a mechanically spinning color wheel is not obviously simpler than a 2M pixel array driven by a complex processor and backlit. Also, a simple count of "failure modes" says nothing; likelihood of failures matters.

    And as LCDs can have pixel failure, certainly DLPs can have pixel failure via individual mirror failures (or the driving electronic pathway)?

    Are there decent stats on failure rates of DLP vs Plasma vs LCD?
     
  2. Jeremy Little

    Jeremy Little Well-Known Member

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    Maybe they've gotten better without the color wheel, but I got a brand new tv under a no-lemon policy on my HLN4365. Here were the repairs:

    1. Color Wheel Whine
    2. DMD chip had 5 pixels that decided to "stick" in the on position creating a spot of nothing but bright white.
    3. Intermittent cycle down - after replacing bulb, ballast, and reseating the safety switch a few times they decided the best option was to cut their losses and replace it.
     
  3. SherardP

    SherardP Well-Known Member

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    LCOS is where its at, then LCD of course.
     
  4. Cpt.America

    Cpt.America Active Member

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    Holycrap that sounds like one SKINNY TV! It would be as long as a football field, and something like 1" high. It would be really hard to watch a movie on a TV screen with an aspect ratio of 30,000 : 1 [​IMG]
     
  5. AmusingistheDawn

    AmusingistheDawn Well-Known Member

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    What is meant by 30,000:1 then?
     
  6. David Norman

    David Norman Premium
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    Contrast ratio is the usual spec -- ratio brightest white:darkest black.

    Since the denominator is so important in this equation, in practical terms for most flat panels it boils down to mean better blacks.

    Aspect ratio in picture Width:Height.
     
  7. AmusingistheDawn

    AmusingistheDawn Well-Known Member

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    Ahhh...well, that was an honest mistake [​IMG]
     
  8. ManW_TheUncool

    ManW_TheUncool Well-Known Member

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    Are you saying the comparison is only meaningful between flat panels, not across to RPTVs, etc? OR do you really believe the various quoted LCD ratios can actually be compared directly to those for DLP RPTVs, etc? Actually, would it even be reasonable to directly compare LCD ratios to plasma ratios? I'm of course assuming we're still talking about manufacturer quote specs, not about the *real* ratios (as might be measured by a reliable, independent 3rd party).

    I kinda doubt it. OTOH, maybe that could be true for absolute black and absolute white, but the ratios don't tell us how everything in between looks, eg. gamma, color fidelity, plus other issues that LCD are notorious for, eg. motion trails/blur. The inexpensive Dell LCD I use for work seems to have pretty impressive absolute black, but it actually sucks badly for much of the curve in between.

    _Man_
     
  9. galenc322

    galenc322 Member

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    I've had my Samsung 61" HLN series DLP for a number of years now, and other than warm up time and viewing angle, I have absolutely no complaints. If it's just two of you watching straight on, then you won't care about viewing angle. I understand the new models have a much wider angle than my old one too. It's even a 720p model, and when watching HD on Dish, the pic is perfect, with no "screen door" affect. And I've never noticed any rainbow effects either. Okay, one complaint: tried to hook up a new Blu-ray player to it with DVI input and couldn't get a picture other than some small window on the screen, even through the RGB inputs. It's an older DLP model and I think it's got something to do with compatibility issues. Other than that, I'd buy another DLP, escpecially if price v.s. size were an issue. [​IMG]
     
  10. David Norman

    David Norman Premium
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    It's honestly hard to know if the quoted contrast specs mean anything since there doesn;t seem to be any consistent way to report measurements. Even within the same company, the quoted specs often vary wildly in the way they are calculated from year to year and even between different models. Dynamic vs static, small window vs full screen, etc.

    When measured by unbiased reviewers in a controlled environment and with a consistent method, the numbers almost never come close to the Bling numbers.

    AT BEST they are a general measure of contrast ratios and black levels. The smarter folks here can likely explain it better than I can, but I would suggest not shopping for TV's based on sales brochures specs in anything other than VERY BROAD strokes. You wouldn't buy a car based on Manufacturers HP or MPG ratings or a Receiver based on 'Power Specs' and those numbers have at least some legal guidelines they have to follow before they add a fudge factor. Look at the TV's, preferably play with the controls and adjust the picture to some sort of normal values and see which one looks better. If you can find some online professional reviews of a particular model at least you might have a reasonable starting point.
     
  11. Brett DiMichele

    Brett DiMichele Well-Known Member

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    I work day in and day out with LCD and Plasma montitors and my money went to DLP.

    My previous set was a 3 CRT RPTV and honestly my eyes and my brain told me the PhlatLight driven Samsung DLP made perfect sense. The switching time of the PhlatLight is unmatchable by any other technology as is the switching time of the DMD. Eliminating the color wheel and the high intensity bulb was what this technology needed to sustain, I can only hope Samsung will step up advertising and keep the tech alive.

    Sadly though, it's cheaper to store Plasma and LCD screens in a warehouse and "wall mounting" is a flashy sales pitch at a B&M store, even though, most will never do it and the depth of these "flat" screens when standing on a base, is as deep as my DLP.


    I chose the HL67A750 and I made the right choice! Viewing angle is better than my last RPTV and I never had an issue with the viewing angles on the last set. Bear in mind if you are going with ANY 67" screen you should be at least 8.0' away and at that distance, you will never encounter an issue with viewing angle.

    Here is a shot of my 67 in my living room with Journey to the center of the Earth on BluRay (not paused) playing on a Samsung BD-1500.

    [​IMG]

    [​IMG]

    This is a photo of my car that was loaded onto a USB drive and plugged into the TV. Of course both of these images have been downsized by PhotoBucket. But they are straight out of the camera, no sharpening or post processing done.

    I've also checked the geometry and out of the box it looked good to me. I did not measure to the inside edge of the bezel to see if there were any measurement differences but it "looked" straight to my calibrated eye ball.

    I have also surfed the net using the TV as a monitor and was equally impressed! Though, 1080x1920 is a bit too large a rez for posting on forums [​IMG]
     
  12. ManW_TheUncool

    ManW_TheUncool Well-Known Member

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    Kool!

    Brett, I read that the geometry on the 67" seems better than the 61" maybe because of a stronger frame/chassis (that doesn't flex so easily like the 61")? Did you find that to be the case? What about the light output for the bigger screen? Don't they both use the same LED light engine?

    I'm sorta eyeing both 61" and 67" for my eventual upgrade. If the price diff isn't that big when I take the plunge, I just might go w/ the 67", especially if the chassis is indeed stronger and yield better geometry.

    Thanks for your input.

    _Man_
     
  13. Brett DiMichele

    Brett DiMichele Well-Known Member

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    Man,

    There is still noticeable flex in the bezel if you push on it. Once the tv is set up, I don't see this being an issue since you are not putting any force on the bezel but I do wish it was made more rigidly.

    I threw up some 1080 test patterns today and was pixel peeping and I do see some slight (1/16th of an inch or less) convergence issue at the upper most right hand corner. It doesn't seem to be an issue on any other side and everything seems to line up well. I am sure I could get into the service menu and adjust the convergence ever so slightly to take care of that corner.

    I believe they are both using the same light engine. I'm guessing the current Phlatlight diodes used are more than bright enough that they work as well on either the 61 or 67. I don't know how much larger they could go before needing a double or triple cluster of each primary color Phlatlight.

    Even with every light on in my living room (two end table lamps, and two five headed spider lamps each with 5 20 watt bulbs) the screen is still bright, vivid and glare free. In fact the only glare I get is from the camera flash and it's very minimal.

    The coatings of the screen work VERY well!

    Right now I have a 4GB flash drive in the TV and I have 2 gigs of music on it and a bunch of 1080P wallpaper, I have one static image setting on the screen with a play list of music going, it's fantastic! I need to shoot some photos of the screen with static 1080P photos on screen.

    Blows me away!
     
  14. Scott Merryfield

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    That has been my experience with the 67-inch set, too. With our old Toshiba 56H80 RP CRT, I had to close the drapes during the daytime to cut down on screen glare and avoid a washed out image. While the new Samsung still looks best in a dark room, I can leave the drapes open during the daytime and still get a very watchable picture.

    Viewing angle has not been an issue, either. We sit about 12 feet away, so the extra screen size of the 67" set over the smaller 61" one is a plus in our room.

    The frame has some flex to it, but geometry seems good to me. I have not brought a grid up on the screen, but the black side bars and top/bottom bars seem straight when watching 4x3 or 2.35:1 material.

    I am very happy with this purchase, and glad I didn't wait too long. We were shopping in Traverse City this past weekend, and rear projection TV's were completely absent from the stores we were in -- Sears, Best Buy, and Wal-Mart. Getting an affordable TV over 52-inches in size may soon become quite difficult.
     
  15. Brett DiMichele

    Brett DiMichele Well-Known Member

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    Yep I am in agreement with Scott!

    Here are some non scientific photos of test patterns and some eye candy wall paper. When I say non scientific I say so because my camera was not aligned to the center point of the screen along the focal plane, yadda yadda... These are just "pictures" not a documentary.

    All the material in these shots is 1080P source (photos from flash drive) and you will notice the minor convergence issue on the right hand of the set. I say minor because it is minor and is only noticed on this one test pattern. You can not detect this on letter boxing or even when surfing the internet. I suspect I can clear this issue up when I get around to it.

    This set is NOT ISF'd it's not even home brew calibrated yet. Currently my blacks are a wee bit too black if you notice in the gray scale bar I don't have much seperation. That's running Dynamic which is basically torch mode and oversaturation.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  16. DaveF

    DaveF Moderator
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    I've never understood the point of photographing of a TV. An uncalibrated display, photographed by an uncalibrated sensor, and re-displayed on another uncalibrated display. What's to be learned? If I go Ooh, Aah, then isn't it nothing more than saying my monitor looks great, or maybe the photographer is really good? What display won't look superb when displayed on a 300x400 box on my 15" laptop screen?

    The zooms of the resolution targets are fine, sure, but typically the photos are of some punch demo scene that really says nothing about anything except if my monitor is any good.

    Not picking on you Brett -- I've been boggling over this for years now. [​IMG]
     
  17. ManW_TheUncool

    ManW_TheUncool Well-Known Member

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    Ooooo... Aaaaaah... [​IMG] [​IMG]

    Yeah, I agree w/ you to some extent, Dave, but it's still pretty cool to see nice looking pics anyway. [​IMG] In this case though, we can probably get a good sense of the geometry issue I was asking about, if nothing else, since color fidelity is (probably) not a significant issue for this (unless the TV somehow requires a compromise between good geometry and good color fidelity). Actually, hmmm... of course, there's also the potential issue of the geometry of the camera lens factoring in here too, if not shot carefully, but oh well... [​IMG]

    BTW, Brett, is that your own photo in the 4th pic (or just some wallpaper you found)? Looks great [​IMG] though (like Dave points out) one can't really tell if that's what it really looks like. If it's yours (and that's really what it looks like, not that you can tell exactly how it actually looks on my monitor [​IMG] ), did you do any sort of PS tweaks to make it (mainly the colors) look like that (beyond just the usual minimal postprocessing whether in-camera or elsewhere)?

    Thanks again for the contribs, y'all...

    _Man_
     
  18. DaveF

    DaveF Moderator
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    [​IMG] I enjoy seeing people's toys. And I agree about seeing the resolution targets and distortion grids.

    But most of the pictures I've seen over the years have been about: look how bright and colorful and good my display looks. Which I think is all bogus. [​IMG]

    Even here, I find this interpretation problem: the resolution target is dimmer on the bottom the the top. I don't know if that's a perception quirk with my eyes, the resolution target's design, caused by camera vignetting, or the TV has sub-par brightness control.

    So, this has nothing to do with DLPs or Brett's TV [​IMG] Just my minor peeve.
     
  19. ManW_TheUncool

    ManW_TheUncool Well-Known Member

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    You're right. [​IMG] Looks like Brett shot these pics from higher than normal eye level (pointing the camera slightly downward). That might be what's causing the dimmer bottom side along w/ the slight bit of perspective distortion (creating a slightly trapezoidal look, instead of rectangular 16x9).

    So actually, I guess there goes my comment about getting a good sense of the TV's geometry too. [​IMG] [​IMG]

    _Man_
     
  20. Brett DiMichele

    Brett DiMichele Well-Known Member

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    Dave,

    You do realize you can click on those 300x400 boxes and get a much larger picture, right? [​IMG] I can upload the original files if you like. As I said in my post these are non scientific, I am not grinding an axe or trying to make any point at all. The grid photos tell the convergence story and that's it... The other photos are just "ohhh fluff" even though my Monitor is calibrated I have no idea if yours is, I have no clue what your color space is (SRGB here), I have no idea what custom settings you may have enabled on your graphics card etc.. I would never post photos of my TV for color reference, heck I can't even get the color of my carpet to turn out right in photos! [​IMG]

    I could shoot my 18% Neutral Gray card with a custom WB and the colors on my side would be accurate [​IMG]

    My camera angle was indeed, too high and digital photography also blows out of proportion the darkening of the screen off angle, you eyes do not perceive what the camera does. Your eyes also don't suffer from target extinction at Nyquist (well, ok, technically they DO, but it's very high) [​IMG] Also our eyes don't add stair step artifacting or Mosiac artifacting.

    But I digress [​IMG]
     

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