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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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 Link Posted: Thu Mar 12, 2009 11:08 am Post subject: |
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| WanMan wrote: | | perisoft wrote: | How the hell do you expect to tell that a digital projector is 'flat' when you're looking at the image it projected after it's been sucked into a digital camera, compressed, transmitted, and displayed on an LCD screen?
You might as well try to judge whether CDs are better than LPs by listening to a recording that was MP3 compressed to 96kbits and played back on a boom box.
A good screenshot of a digital projector projected in the right environment will be nigh-on *identical* to the raw source material in the bluray disc. Pretensions to "oh, this jacket is 3D on this screenshot and not in the other" are pretty close to delusional. |
Image depth through the performance of contrast is not abnormal of a construct. You actually cannot accept this? |
Not when it's been photographed, compressed, and displayed on some random, uncalibrated LCD screen, and used to judge the original, no.
If screenshots are supposed to be usable to judge the quality of the display that showed the original material, then a raw grab straight off the disc to your LCD monitor ought to have perfect, gorgeous 3D. Or, hell, if you can see 'depth' in a screenshot shown on an LCD monitor, why not just put the screenshot of a G90 on your digital projector and get the depth back?
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kal
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Joined: 06 Mar 2006
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WanMan
Joined: 19 Mar 2006
Posts: 10273
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| Link Posted: Fri Mar 13, 2009 11:00 pm Post subject: |
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| perisoft wrote: | | WanMan wrote: | | perisoft wrote: | How the hell do you expect to tell that a digital projector is 'flat' when you're looking at the image it projected after it's been sucked into a digital camera, compressed, transmitted, and displayed on an LCD screen?
You might as well try to judge whether CDs are better than LPs by listening to a recording that was MP3 compressed to 96kbits and played back on a boom box.
A good screenshot of a digital projector projected in the right environment will be nigh-on *identical* to the raw source material in the bluray disc. Pretensions to "oh, this jacket is 3D on this screenshot and not in the other" are pretty close to delusional. |
Image depth through the performance of contrast is not abnormal of a construct. You actually cannot accept this? |
Not when it's been photographed, compressed, and displayed on some random, uncalibrated LCD screen, and used to judge the original, no.
If screenshots are supposed to be usable to judge the quality of the display that showed the original material, then a raw grab straight off the disc to your LCD monitor ought to have perfect, gorgeous 3D. Or, hell, if you can see 'depth' in a screenshot shown on an LCD monitor, why not just put the screenshot of a G90 on your digital projector and get the depth back?
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I still by my position, and my question.
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km987654
Joined: 25 Jul 2007
Posts: 2857
Location: Australia
TV/Projector: Barco BG809s
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| Link Posted: Sat Mar 14, 2009 3:13 am Post subject: |
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Contrast (from black) is what delivers depth of field. Contrast is still superior on CRTs and therefore I would expect that depth of field or the 3D feel of the image would be superior on a CRT.
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Link Posted: Sat Mar 14, 2009 1:51 pm Post subject: |
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| km987654 wrote: | | Contrast (from black) is what delivers depth of field. Contrast is still superior on CRTs and therefore I would expect that depth of field or the 3D feel of the image would be superior on a CRT. |
You're referring to ANSI contrast - the difference between the darkest and lightest parts of a scene containing both. CRTs are great at absolute black - but obviously a full black screen doesn't do much for depth.
CRTs, however, are absolutely AWFUL at ANSI contrast, even LC CRTs - and ANSI is what could provide the intra-scene contrast you describe. If ANSI determines '3D feel', then CRTs should be awful and digitals fantastic.
As an example, if I have a scene with, say, a shot from inside showing a really bright open doorway, and two characters -inside- in the very dark room, the dark parts of the room will be much higher contrast on a digital than on a CRT, because on a CRT the light from the bright doorway will wash everything else out. Digitals can expect -genuine- 1000:1 or 2000:1 contrast for both on/off and ANSI; LC CRTs, if I'm not mistaken, can expect 30k:1 on/off and at best 500:1 ANSI.
When the door shuts and the room is mostly very dark, the CRT will get the advantage back.
This isn't as simple as "CRTs rule, digitals suck" - that point of view suggests little knowledge of imaging and a tendency toward middle-school "my dad can beat up your dad" bull****.
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AnalogRocks
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Joined: 08 Mar 2006
Posts: 26690
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Link Posted: Sat Mar 14, 2009 5:41 pm Post subject: |
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Ohhh yeah! Well my CRT projector can beat up your flat panel! 
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km987654
Joined: 25 Jul 2007
Posts: 2857
Location: Australia
TV/Projector: Barco BG809s
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| Link Posted: Sun Mar 15, 2009 3:30 am Post subject: |
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| perisoft wrote: | | km987654 wrote: | | Contrast (from black) is what delivers depth of field. Contrast is still superior on CRTs and therefore I would expect that depth of field or the 3D feel of the image would be superior on a CRT. |
You're referring to ANSI contrast - the difference between the darkest and lightest parts of a scene containing both. CRTs are great at absolute black - but obviously a full black screen doesn't do much for depth.
CRTs, however, are absolutely AWFUL at ANSI contrast, even LC CRTs - and ANSI is what could provide the intra-scene contrast you describe. If ANSI determines '3D feel', then CRTs should be awful and digitals fantastic.
As an example, if I have a scene with, say, a shot from inside showing a really bright open doorway, and two characters -inside- in the very dark room, the dark parts of the room will be much higher contrast on a digital than on a CRT, because on a CRT the light from the bright doorway will wash everything else out. Digitals can expect -genuine- 1000:1 or 2000:1 contrast for both on/off and ANSI; LC CRTs, if I'm not mistaken, can expect 30k:1 on/off and at best 500:1 ANSI.
When the door shuts and the room is mostly very dark, the CRT will get the advantage back.
This isn't as simple as "CRTs rule, digitals suck" - that point of view suggests little knowledge of imaging and a tendency toward middle-school "my dad can beat up your dad" bull****. |
Well done and no problem with what you have put forward.
If the scene is uniform say like the waterfall scene then shouldn't the on/off contrast be the influencing factor. I take your point about the outdoor indoor shot but if the scene is iniform (no bright backlight) then the on/off 30K would be what produces 3D.
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Link Posted: Sun Mar 15, 2009 4:05 am Post subject: |
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| km987654 wrote: |
Well done and no problem with what you have put forward.
If the scene is uniform say like the waterfall scene then shouldn't the on/off contrast be the influencing factor. I take your point about the outdoor indoor shot but if the scene is iniform (no bright backlight) then the on/off 30K would be what produces 3D. |
Actually, no - think about it this way: The more uniform the scene, the less contrast matters. A scene showing a barely visible silhouette in a bank of fog needs almost no contrast at all - even the most horrible passive matrix monochrome LCD monitor could manage it. But a scene with a silhouette against a blinding sunrise is far different - and there, high ANSI contrast will make the silhouette much darker than it would be with low ANSI contrast.
A figure silhouetted against a bright yellow sun will be orange with low ANSI, and black(er) with high ANSI.
A starfield - a jet black scene with tiny pinpricks of light - will be rendered incredibly well on a CRT, with very high on/off contrast, and poorly on a digital projector with bad black level. The opening space scenes in WALL-E are staggeringly beautiful on my CRT; the later scenes on the spaceship, with lots of shiny white walls and jet black shadows and accents, are probably not NEARLY as punchy as they would be with LC or a digital.
Another thing to consider here is that bad room treatment will ruin the advantage of a high ANSI projector - if your HT is white (or even medium gray), any light on the screen will bounce all over the place and end up all over the OTHER parts of the screen, making ANSI terrible no matter WHAT'S projecting on it. If you have a white room, you might as well get an AC CRT projector and at least have pure black fadeouts, because ain't nothin' gonna help intrascene contrast!
Bad ANSI (and, by extension, the difference between LC and AC CRTs) is only an issue with a really dark, matte-painted or fabric'd room. Like mine, with my AC CRT projector. 
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km987654
Joined: 25 Jul 2007
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Location: Australia
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| Link Posted: Sun Mar 15, 2009 4:50 am Post subject: |
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I have learned a lot today thanks.
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Person99
Joined: 09 Mar 2006
Posts: 4901
Location: Flower Mound, TX
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| Link Posted: Wed Jun 10, 2009 9:21 pm Post subject: |
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| AnalogRocks wrote: | | stgdz wrote: | | Do digitals display a flat image? |
Not on a curved screen
I've seen a couple of digital projectors and I'm underwhelmed. I saw the Mitsubishi HC5000, the picture looked dull, it was pixelated and everyone needed some clearsil to wash their faces with, and the trees, sky, cars, grass etc... Plus everyone had a clayface.
Go see some digital projectors for yourself. They may look OK to you. I wouldn't spend any money on one. |
One big "problem" with digitals is that they all look different. CRTs all pretty much look the same with just subtle differences. I for one think the HC5000 looks like crap. My next door neighbor has one and I currently have a "higher end" last generation 720p DLP in my theater. Everyone thinks my projector looks better than the HC5000 and it does. Funny thing is, not one person has ever commented that mine is lower resolution (because it is not obvious).
I'm not a fan of:
- Dynamic Iris
- LCD
But YMMV.
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A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Person99
Joined: 09 Mar 2006
Posts: 4901
Location: Flower Mound, TX
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| Link Posted: Wed Jun 10, 2009 9:35 pm Post subject: |
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| perisoft wrote: |
A starfield - a jet black scene with tiny pinpricks of light - will be rendered incredibly well on a CRT, with very high on/off contrast, and poorly on a digital projector with bad black level. The opening space scenes in WALL-E are staggeringly beautiful on my CRT; the later scenes on the spaceship, with lots of shiny white walls and jet black shadows and accents, are probably not NEARLY as punchy as they would be with LC or a digital. |
This is largely true. But there is a subtle aspect of human perception. If a star field is sparse enough (say APL of 5%), then the CRT will be clearly superior because the background will be very black and the there is no current limiting to make the stars less bright. In this situation, the CRT is steller (its black is black and its intrascene or "ANSI CR" is actually approaching its on/off CR). A digital on the scene will have far less intrascene contrast than the CRT.
Now, once the APL crosses a point somewhere between 40-60%, things change for many reasons. Some include:
1) Due to the way the human iris works, the blacks now look black even if they are gray due to the brightness causeing the closing down of the iris (there are optical illusions showing this where a grey dot looks grey on a black field, but black on a white field).
2) In your white walls scene, the CRT has to challenges: poor "true" ANSI CR and it has to limit the current, so you white is kind of "dingy".
Basically, to put what perisoft said simply: p to an APL of about 40-60, on/off CR is king; for APLs above that, ANSI CR is king.
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A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
Last edited by Person99 on Wed Jun 10, 2009 9:46 pm; edited 1 time in total
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Person99
Joined: 09 Mar 2006
Posts: 4901
Location: Flower Mound, TX
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| Link Posted: Wed Jun 10, 2009 9:46 pm Post subject: |
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| perisoft wrote: | | on a CRT the light from the bright doorway will wash everything else out. Digitals can expect -genuine- 1000:1 or 2000:1 contrast for both on/off and ANSI; LC CRTs, if I'm not mistaken, can expect 30k:1 on/off and at best 500:1 ANSI. |
Acutally, the best ANSI CR for any LC CRT PJ is about 230:1-most LC are less than 180:1 and most LC less than 130:1. 500:1 is way higher than they can achieve.
Most CRTs is their environment without black crushing (even with gamma mods) don't get quite 30K:1.
With digitals, on/off can be what the panel does, what the light engine does, or what the PJ does (including dynamic iris and such). By "genuine" CR I'm assuming you are meaning no dynamic iris. However, I must point out that no digital has about the same on/off and ANSI. Digitals very considerably by technology and implementation.
Couple cases in point:
- My DLP has a "genuine" on/off (measured) at just under 3200:1. It's ANSI CR (measured) at 647:1.
- An RS20 has an on/off of about 40K:1 and an ANSI CR of about 250:1.
For reference, I've measured another DLP using the same chip as mine and it only had an on/off of about 2800:1 and an ANSI of about 450:1--so implementation is a big factor in digitals.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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