How much black level I can get from PJ ? - Page 2 - AVS Forum
Forum Jump: 
 10Likes
Reply
 
Thread Tools
post #31 of 60 Old 07-28-2014, 08:29 AM
AVS Club Gold
 
AV Science Sales 5's Avatar
 
Join Date: Sep 2011
Location: A beautiful view of a lake
Posts: 7,548
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 277 Post(s)
Liked: 402
This is why I talked about black level in my post and not contrast. It is the room that effect black level the most.

Mike Garrett, AV Science Sales Call Me: 585-671-2968
Email Me:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Brands we sell: 
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
 
Call for B-stock projectors
Stewart, Seymour, SE, SI, Falcon & many more.
RBH, Martin Logan, Triad, Atlantic Technology, MK Sound, BG Radia, SVS & Def Tech.
AV Science Sales 5 is online now  
Sponsored Links
Advertisement
 
post #32 of 60 Old 07-28-2014, 05:14 PM
AVS Addicted Member
 
DavidHir's Avatar
 
Join Date: Dec 2004
Posts: 10,384
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 153 Post(s)
Liked: 423
So, for example, a JVC will have the exact same on/off contrast ratio in a bright room with white walls, white carpet, and bright overhead light vs in a black pit? Hmmm. I find that scenario hard to believe.

I could see where a moderately dark room vs a black pit will pose little to no difference in on/off, but at some point room brightness (or whatever you like to call it) has to play a factor in on/off.

DavidHir is online now  
post #33 of 60 Old 07-28-2014, 05:24 PM
AVS Special Member
 
Seegs108's Avatar
 
Join Date: Jul 2007
Location: Schenectady, New York
Posts: 4,083
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 222
Quote:
Originally Posted by DavidHir View Post
So, for example, a JVC will have the exact same on/off contrast ratio in a bright room with white walls, white carpet, and bright overhead light vs in a black pit? Hmmm. I find that scenario hard to believe.

I could see where a moderately dark room vs a black pit will pose little to no difference in on/off, but at some point room brightness (or whatever you like to call it) plays a factor in on/off.
That isn't what Mark is saying. There can't be ambient light (or any other light source in the room). Mark is talking about the room itself. Nothing more and nothing less. On/Off contrast will remain the same. If the projector is the only light source in the room that is the case and like he said, there's nothing to argue about. Another example of this "phenomenon" is when you take screen gain into consideration. On a High Power screen, for example, you get a real world gain of about 1.8. This means the image is 1.8 times brighter throughout the whole spectrum. That is, peak white and black level are are 1.8 times brighter. The amount of on/off contrast doesn't change. The range just shifts up or down (in this case up) depending on the gain of the screen. Think of the room as screen gain. The reflections within the room will shift the on/off spectrum like screen gain does.

I believe this is what Mark is trying to say. If I'm wrong, I'm sure he'll correct me.

----------------------------------------------------------------------------

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by Seegs108; 07-28-2014 at 05:28 PM.
Seegs108 is offline  
post #34 of 60 Old 07-28-2014, 06:30 PM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
Seegs has explained what I am saying quite well. Ambient light adds to the peak but nowhere to extent it adds to the black ref level and destroys the ratio. Reflected light from the walls assuming linear reflectivity adds the same multiplier to the peak and the blck ref value and cancel out i the division used to calculate the on off ratio.

A black pit room will give you the black ref level you are paying for and will give you nar the ANSI that is coming out of your lens.. Not exactly though because of bleed caused by the screen.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536
mark haflich is offline  
post #35 of 60 Old 07-28-2014, 07:44 PM
AVS Special Member
 
Ericglo's Avatar
 
Join Date: Oct 2004
Location: Just below the US in South Florida
Posts: 6,261
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Liked: 42
http://www.hometheaterhifi.com/volum...06-part-1.html

Since you alluded to it earlier Mark. It has been so long, but IIRC Darin wanted to correct something in the article. I can't remember what his issue was.


On a side note, I did a search on Darin's name and Kei's photo album came up. I haven't seen her in like five years along with a bunch of other former Cedia attendees. Maybe we need a thread on whatever happened to?

My new favorite game is Stop the Bots
Ericglo is offline  
post #36 of 60 Old 07-28-2014, 08:16 PM
AVS Addicted Member
 
DavidHir's Avatar
 
Join Date: Dec 2004
Posts: 10,384
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 153 Post(s)
Liked: 423
Quote:
Originally Posted by Seegs108 View Post
That isn't what Mark is saying. There can't be ambient light (or any other light source in the room). Mark is talking about the room itself. Nothing more and nothing less. On/Off contrast will remain the same. If the projector is the only light source in the room that is the case and like he said, there's nothing to argue about. Another example of this "phenomenon" is when you take screen gain into consideration. On a High Power screen, for example, you get a real world gain of about 1.8. This means the image is 1.8 times brighter throughout the whole spectrum. That is, peak white and black level are are 1.8 times brighter. The amount of on/off contrast doesn't change. The range just shifts up or down (in this case up) depending on the gain of the screen. Think of the room as screen gain. The reflections within the room will shift the on/off spectrum like screen gain does.

I believe this is what Mark is trying to say. If I'm wrong, I'm sure he'll correct me.
Gotcha, that clears it up.

So, are the terms "native" contrast and "on/off" contrast meant to be the same?

DavidHir is online now  
post #37 of 60 Old 07-28-2014, 08:43 PM
AVS Addicted Member
 
R Harkness's Avatar
 
Join Date: May 2001
Location: Toronto, Ontario, Canada
Posts: 11,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked: 321
Quote:
Originally Posted by DavidHir View Post
Gotcha, that clears it up.

So, are the terms "native" contrast and "on/off" contrast meant to be the same?
"Native Contrast" generally refers to what the chip/light/engine/system can pull off on it's own, without a Dynamic Iris.

Typically we talk about "native on/off" contrast, which is sequential contrast, meaning a measurement first with a full white screen image ("on" measurement) and then after that, measure the projector projecting a full black image ("off" measurement). Do that gives you the full on/off dynamic range of the native system. So for instance a JVC projector can be measured with a 50,000:1 on/off contrast range (even higher depending on who is measuring). So that's the distance between the darkest black it can put out and it's brightest white.

Ideally that would mean that you could have that kind of simultaneous contrast as well - in other words, say you have a shot at night with a pitch black background, and a very bright searchlight peircing the black night. If the projector could simultaneously produce it's darkest black and it's brightest white, that is do 50,000:1 contrast in that single image, it would be a very dynamic image. Unfortunately, there are various ways in which the bright part of the image is not perfectly contained and the light bleeds and diffuses in to the dark areas. It happens at the chip level, at the lens level etc (others can get more technical about that). The upshot is that actually maintaining that kind of simultaneous contrast, due to light bleed in the system, doesn't really happen.

ANSI contrast measurements attempt to determine how much simultaneous contrast (the less light bleed in the system the better) by displaying dark squares and bright squares together, measuring how dark and bright they are simultaneously.

However, as some very smart folks on the forum have pointed out, the type of pattern used to measure the simultaneous ANSI contrast is not typical of most movie images, and since the light and dark areas of many movie images are more spread out, the light bleed becomes less severe in so you get higher contrast. This is why ANSI contrast doesn't really tell you how contrasty an image will be. It turns out that a higher native on/off contrast ratio comes into play here, which is why the JVCs can in certain dark scenes with light objects look more contrasty and dynamic than another projector that measures "higher ANSI contrast" in the ANSI patterns.

Which is what I was getting at before: In making a dark room you are preserving these type of contrast dynamics that a high contrast projector like the JVC can deliver.

Now, as to whether "native on/off" is the SAME as "on/off" contrast...not really. The distinction to be made is generally due to the existence of projectors that use Dynamic Irises to increase their on/off contrast ratio. A Sony projector has much lower native on/off contrast than a JVC, but in adding a DI to close down and cut off more light for certain dark scenes (and full black screens) the Sony is able to produce a deeper black level at times than if it didn't have the DI. So in measuring the on/off contrast with the DI engaged, on a full black screen the DI will close down lowering the light output and hence lowering the measured black level. Put on a full white screen and
the DI opens up no longer limiting the light output, so you measure the brightest the projector can put out.
Hence using the DI you get a higher on/off contrast measurement than the native contrast of the system.
That's why people will refer to "native" on/off contrast to distinguish it from contrast possible adding a Dynamic Iris which dynamically lowers light output for dark images. Some projectors look to have really high on/off contrast with the DI working. Turn it off and their native on/off contrast is much lower.

The issue with DI's as I believe you know is that in order to lower the light level for dark scenes, they are also cutting off all the light output, so making everything dimmer including the objects that should be bright in the shot.
Whereas a high native contrast projector (e.g. JVC) can produce a higher contrast of dark and light in the same image without a DI. (And to compensate for this, projectors employing a DI will often manipulate the gamma to boost the brightness of lighter parts in a dark scene, to boost the contrast).

Anyway....

Rich H


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by R Harkness; 07-29-2014 at 10:44 AM. Reason: fixed typo in first sentence, which originally incorrectly read "with" dynamic iris
R Harkness is online now  
post #38 of 60 Old 07-28-2014, 08:45 PM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
Native is short for native on/off contrast ratio. Add a dynamic iris etc and now its dynamic on/off contrast ratio.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536
mark haflich is offline  
post #39 of 60 Old 07-28-2014, 08:47 PM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
Quote:
Originally Posted by Ericglo View Post
http://www.hometheaterhifi.com/volum...06-part-1.html

Since you alluded to it earlier Mark. It has been so long, but IIRC Darin wanted to correct something in the article. I can't remember what his issue was.


On a side note, I did a search on Darin's name and Kei's photo album came up. I haven't seen her in like five years along with a bunch of other former Cedia attendees. Maybe we need a thread on whatever happened to?
Kei closed her business. She worked for AV Science for a while sometime after that. From what I know she is doing fine.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536
mark haflich is offline  
post #40 of 60 Old 07-28-2014, 09:01 PM
Member
 
Debonaire's Avatar
 
Join Date: Apr 2014
Posts: 171
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Liked: 20
There are also other tricks to increase contrast like over saturating your primaries. TI does this for their led projectors.
Debonaire is offline  
post #41 of 60 Old 07-28-2014, 09:05 PM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
Quote:
Originally Posted by R Harkness View Post
"Native Contrast" generally refers to what the chip/light/engine/system can pull off on it's own, with a Dynamic Iris.
Typically we talk about "native on/off" contrast, which is sequential contrast, meaning a measurement first with a full white screen image ("on" measurement) and then after that, measure the projector projecting a full black image ("off" measurement). Do that gives you the full on/off dynamic range of the native system. So for instance a JVC projector can be measured with a 50,000:1 on/off contrast range (even higher depending on who is measuring). So that's the distance between the darkest black it can put out and it's brightest white.

Ideally that would mean that you could have that kind of simultaneous contrast as well - in other words, say you have a shot at night with a pitch black background, and a very bright searchlight peircing the black night. If the projector could simultaneously produce it's darkest black and it's brightest white, that is do 50,000:1 contrast in that single image, it would be a very dynamic image. Unfortunately, there are various ways in which the bright part of the image is not perfectly contained and the light bleeds and diffuses in to the dark areas. It happens at the chip level, at the lens level etc (others can get more technical about that). The upshot is that actually maintaining that kind of simultaneous contrast, due to light bleed in the system, doesn't really happen.

ANSI contrast measurements attempt to determine how much simultaneous contrast (the less light bleed in the system the better) by displaying dark squares and bright squares together, measuring how dark and bright they are simultaneously.

However, as some very smart folks on the forum have pointed out, the type of pattern used to measure the simultaneous ANSI contrast is not typical of most movie images, and since the light and dark areas of many movie images are more spread out, the light bleed becomes less severe in so you get higher contrast. This is why ANSI contrast doesn't really tell you how contrasty an image will be. It turns out that a higher native on/off contrast ratio comes into play here, which is why the JVCs can in certain dark scenes with light objects look more contrasty and dynamic than another projector that measures "higher ANSI contrast" in the ANSI patterns.

Which is what I was getting at before: In making a dark room you are preserving these type of contrast dynamics that a high contrast projector like the JVC can deliver.

Now, as to whether "native on/off" is the SAME as "on/off" contrast...not really. The distinction to be made is generally due to the existence of projectors that use Dynamic Irises to increase their on/off contrast ratio. A Sony projector has much lower native on/off contrast than a JVC, but in adding a DI to close down and cut off more light for certain dark scenes (and full black screens) the Sony is able to produce a deeper black level at times than if it didn't have the DI. So in measuring the on/off contrast with the DI engaged, on a full black screen the DI will close down lowering the light output and hence lowering the measured black level. Put on a full white screen and
the DI opens up no longer limiting the light output, so you measure the brightest the projector can put out.
Hence using the DI you get a higher on/off contrast measurement than the native contrast of the system.
That's why people will refer to "native" on/off contrast to distinguish it from contrast possible adding a Dynamic Iris which dynamically lowers light output for dark images. Some projectors look to have really high on/off contrast with the DI working. Turn it off and their native on/off contrast is much lower.

The issue with DI's as I believe you know is that in order to lower the light level for dark scenes, they are also cutting off all the light output, so making everything dimmer including the objects that should be bright in the shot.
Whereas a high native contrast projector (e.g. JVC) can produce a higher contrast of dark and light in the same image without a DI. (And to compensate for this, projectors employing a DI will often manipulate the gamma to boost the brightness of lighter parts in a dark scene, to boost the contrast).

Anyway....
Rich. Another excellent post.

However I would quibble with a few statements. Native on/off contrast or dynamic on/off contrast is not a distance between white and black. It is a ratio of the values and as a ratio has no dimensionality. It is a pure number with no unit of length or distance. The values measured have dimensionality but the calculation of the ratio cancels those units.e, distaneAnd that is implicit in the full terms, native on/off contrast ratio and dynamic on off contrast ratio.


Your statement that native on off is not really the same as on off contrast if by on off contrast one means dynamic on/off contrast. Normally on/off contrast means native on/off contrast and any reference to dynamic on/off contrast requires the modifier dynamic in front of it. Now when we refer to dynamic irises we deviate because of advertising and lack of humility in JVC's case using the word intelligent as in intelligent iris because they are simply to shamed given their long and now discarded position on dynamic iris and dynamic on/off contrast ratios. or some other modifier such as JVC's lame, no super lame, modifier intelligent. I guess they finally smartened up as to the benefits of a dynamic iris or at least the need for one so their contrast ratio (dynamic) would be competitive. These terms fail to tell the reader whether such things as dynamic gamma and lamp dimming etc are employed as part of the dynamic process.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536

Last edited by mark haflich; 07-28-2014 at 09:14 PM.
mark haflich is offline  
post #42 of 60 Old 07-28-2014, 09:15 PM
AVS Special Member
 
Seegs108's Avatar
 
Join Date: Jul 2007
Location: Schenectady, New York
Posts: 4,083
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 222
Quote:
Originally Posted by Debonaire View Post
There are also other tricks to increase contrast like over saturating your primaries. TI does this for their led projectors.
I don't quite follow your thought process on this. For starters TI doesn't manufacture projectors and their DMDs only work in greyscale. So TI is not at fault if this were true. The LEDs in their "native" color gamut are more saturated but this can be calibrated out and most, if not all, professional reviewers would only give on/off numbers for a calibrated LED projector. They would specify if on/off was measured before calibration. I also don't see how higher saturated colors would increase on/off measurements since it's peak white and black level. Are you trying to suggest oversaturated colors produce a darker black and a brighter white?

Currently I have an LS-100D and this is it's native gamut:



I'd say it is highly oversaturated and Rec 709 content looks cartoonish when viewed. So even if this were true, no one would actually want to view the content like this to gain a relatively small amount of contrast.

----------------------------------------------------------------------------

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by Seegs108; 07-28-2014 at 09:18 PM.
Seegs108 is offline  
post #43 of 60 Old 07-28-2014, 09:57 PM
Member
 
Debonaire's Avatar
 
Join Date: Apr 2014
Posts: 171
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Liked: 20
TI makes the drivers and has a color remaping algorithm for use with LED. TI is very much at "fault." Their draconian business model only allows certain configurations that you must design around.

To make it simple, TI researched(outsourced) how we perceive color in order to expand color beyond what REC 709 define in order to fake cinema gamut. They then use a table of values which goes beyond what you did by over saturating alone.

The result isn't small. LED has about a quarter brightness lost in the spectrum outside the REC gamut.

Last edited by Debonaire; 07-28-2014 at 10:03 PM.
Debonaire is offline  
post #44 of 60 Old 07-28-2014, 11:11 PM
AVS Special Member
 
Seegs108's Avatar
 
Join Date: Jul 2007
Location: Schenectady, New York
Posts: 4,083
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 222
So if the brightness loss is only outside the Rec 709 gamut, what happens when you calibrate the projector? Is there any difference? My point is if there's no difference when you calibrated why even mention it. No one uses these native gamuts if they're serious about color.
Seegs108 is offline  
post #45 of 60 Old 07-28-2014, 11:32 PM
Member
 
Debonaire's Avatar
 
Join Date: Apr 2014
Posts: 171
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Liked: 20
Quote:
Originally Posted by Seegs108 View Post
So if the brightness loss is only outside the Rec 709 gamut, what happens when you calibrate the projector? Is there any difference? My point is if there's no difference when you calibrated why even mention it. No one uses these native gamuts if they're serious about color.
I was only mentioning how to increase contrast. If anyone serious about contrast will get a G90 or Barco 909. Any digital is also a compromise. I doubt anyone getting an led projector is anal like us.

But a CRT is a compromise in sanity for size and use. The color and sharpness isn't as good a digital and is a compromise too.

Anyone interested in reality, unlike us, won't care about this serious color.
Debonaire is offline  
post #46 of 60 Old 07-29-2014, 12:01 AM
AVS Special Member
 
Elix's Avatar
 
Join Date: Jun 2011
Location: Dungeon, Pillar of Eyes
Posts: 1,212
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Liked: 24
The trick to achieving more intra-scene contrast is higher gamma. The difference in 2.2 and 2.5 pure power is quite dramatic but one has to understand undesirable effects of using higher gamma on most content and display devices: color shifts, near black details crush. Still higher gamma can compensate for the lack of native contrast in some cases.
Elix is offline  
post #47 of 60 Old 07-29-2014, 06:02 AM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
And the secret to high gamma is a high on/off contrast ratio as I have said in previous posts. And in norder to have enough on/off to run a 2.5 you can not rely on native on/off. To my knowledge, none of the JVCs or Sonys can do a 2.5 gamma without there versions of dynamic irises engaged. Of course one can tweak the gamma curve a bit at the low end and for that matter at the high end to make up for deficiencies in native on/off.

Is great to play with and post about all this stuff. I just put my Sony on the 2.2 gamma preset and watch my sports. For movies, I put it at 2.4 and watch.

I watch a movie once, maybe twice depending. I don't go back and watch clips to compare. I just don't. My system is a meansvto the end and is not the end. My youth with CRTs was spent watching clips from the 5th Element, over and over on different projectors and with different source discs. It was 5 years before I ever watched the whole thing from beginning to end.

And why a G90 or Barco 909. What's wrong with a Electrohome 9500LC Ultra? LC (liquid coupling of the tube to the lens) is very important for getting the ANSI contrast up.

Though I no longer own or use a CRT projector, I still actively participate with a group of CRTers. We get together about twice a year and travel thousands of miles to do it. I here there will be a meet at Kosman's in Oct in Norther VA. As the boys know, it uses a blend of two Electrohomes.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536
mark haflich is offline  
post #48 of 60 Old 07-29-2014, 07:13 AM
Senior Member
 
ajvandenb's Avatar
 
Join Date: Oct 2008
Posts: 340
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 11
Quote:
Originally Posted by mks_95 View Post
Hi every one..



Since I am a kuro member ( God bless it soul :-D)



I was wondering, if I prepare a pat cave room, and a decent projector screen, with a projector costing 5000$-10000$ for example any latest JVCs pj

( how much black level I will get, since my kuro PRO 101 reached 0.0005fL)
I have an X35 in a black pit and also have a Kuro 101. Don't get me wrong the black levels of the JVC for a projector are amazing. However, it doesn't even get close to the KURO in the same room when it comes to black levels. Now back to the contrast discussions!!
ajvandenb is online now  
post #49 of 60 Old 07-29-2014, 07:46 AM
AVS Addicted Member
 
DavidHir's Avatar
 
Join Date: Dec 2004
Posts: 10,384
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 153 Post(s)
Liked: 423
Quote:
Originally Posted by R Harkness View Post
"Native Contrast" generally refers to what the chip/light/engine/system can pull off on it's own, with a Dynamic Iris.
Typically we talk about "native on/off" contrast, which is sequential contrast, meaning a measurement first with a full white screen image ("on" measurement) and then after that, measure the projector projecting a full black image ("off" measurement). Do that gives you the full on/off dynamic range of the native system. So for instance a JVC projector can be measured with a 50,000:1 on/off contrast range (even higher depending on who is measuring). So that's the distance between the darkest black it can put out and it's brightest white.

Ideally that would mean that you could have that kind of simultaneous contrast as well - in other words, say you have a shot at night with a pitch black background, and a very bright searchlight peircing the black night. If the projector could simultaneously produce it's darkest black and it's brightest white, that is do 50,000:1 contrast in that single image, it would be a very dynamic image. Unfortunately, there are various ways in which the bright part of the image is not perfectly contained and the light bleeds and diffuses in to the dark areas. It happens at the chip level, at the lens level etc (others can get more technical about that). The upshot is that actually maintaining that kind of simultaneous contrast, due to light bleed in the system, doesn't really happen.

ANSI contrast measurements attempt to determine how much simultaneous contrast (the less light bleed in the system the better) by displaying dark squares and bright squares together, measuring how dark and bright they are simultaneously.

However, as some very smart folks on the forum have pointed out, the type of pattern used to measure the simultaneous ANSI contrast is not typical of most movie images, and since the light and dark areas of many movie images are more spread out, the light bleed becomes less severe in so you get higher contrast. This is why ANSI contrast doesn't really tell you how contrasty an image will be. It turns out that a higher native on/off contrast ratio comes into play here, which is why the JVCs can in certain dark scenes with light objects look more contrasty and dynamic than another projector that measures "higher ANSI contrast" in the ANSI patterns.

Which is what I was getting at before: In making a dark room you are preserving these type of contrast dynamics that a high contrast projector like the JVC can deliver.

Now, as to whether "native on/off" is the SAME as "on/off" contrast...not really. The distinction to be made is generally due to the existence of projectors that use Dynamic Irises to increase their on/off contrast ratio. A Sony projector has much lower native on/off contrast than a JVC, but in adding a DI to close down and cut off more light for certain dark scenes (and full black screens) the Sony is able to produce a deeper black level at times than if it didn't have the DI. So in measuring the on/off contrast with the DI engaged, on a full black screen the DI will close down lowering the light output and hence lowering the measured black level. Put on a full white screen and
the DI opens up no longer limiting the light output, so you measure the brightest the projector can put out.
Hence using the DI you get a higher on/off contrast measurement than the native contrast of the system.
That's why people will refer to "native" on/off contrast to distinguish it from contrast possible adding a Dynamic Iris which dynamically lowers light output for dark images. Some projectors look to have really high on/off contrast with the DI working. Turn it off and their native on/off contrast is much lower.

The issue with DI's as I believe you know is that in order to lower the light level for dark scenes, they are also cutting off all the light output, so making everything dimmer including the objects that should be bright in the shot.
Whereas a high native contrast projector (e.g. JVC) can produce a higher contrast of dark and light in the same image without a DI. (And to compensate for this, projectors employing a DI will often manipulate the gamma to boost the brightness of lighter parts in a dark scene, to boost the contrast).

Anyway....
Great post and explanation.

DavidHir is online now  
post #50 of 60 Old 07-29-2014, 08:52 AM
AVS Special Member
 
Kris Deering's Avatar
 
Join Date: Oct 2002
Location: The Pacific Northwet
Posts: 7,094
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 198 Post(s)
Liked: 338
Quote:
Originally Posted by Debonaire View Post
TI makes the drivers and has a color remaping algorithm for use with LED. TI is very much at "fault." Their draconian business model only allows certain configurations that you must design around.

To make it simple, TI researched(outsourced) how we perceive color in order to expand color beyond what REC 709 define in order to fake cinema gamut. They then use a table of values which goes beyond what you did by over saturating alone.

The result isn't small. LED has about a quarter brightness lost in the spectrum outside the REC gamut.
The only thing that making the primaries brighter would do is increase on/off contrast ratio on the high end (white), not the lower end. Ultimately I think most people would rather have their on/off contrast increased by lowering the black floor. This is also the problem with a white room. Yes, a white room with no lights has no effect on on/off contrast ratio as it will raise both white and black equally BUT this in turn DOES raise the black floor which is what you want to avoid to get the rich contrasty image most people want. A white room will also destroy simultaneous contrast (though an improperly setup black room can as well) as Mark has already pointed out. Mark and I have a ST100 screen which is fantastic, but it also creates its own problems in regards to ANSI or simultaneous contrast due to its inability to reject light from different angles. You better be VERY sure you have exceptional light control if you want to use a screen like this.

Flat panels are a completely different matter. One, they have substantially smaller images that you sit farther away from so that alone provides a completely different perception value. They are quite a bit brighter, which will bias your eyes (on top of any ambient lighting) thereby increasing perceptual contrast. They also tend to have far higher MTF. ANSI plays a big part, but there is a multitude of reasons that mixed or simultaneous contrast looks better on flat panels. But absolutely blacks typically do not.

Quote:
Originally Posted by Debonaire View Post
I was only mentioning how to increase contrast. If anyone serious about contrast will get a G90 or Barco 909. Any digital is also a compromise. I doubt anyone getting an led projector is anal like us.

But a CRT is a compromise in sanity for size and use. The color and sharpness isn't as good a digital and is a compromise too.

Anyone interested in reality, unlike us, won't care about this serious color.
I think we've reached a point where the black levels of the best digital projectors have reached the point where they are as good if not better than the best CRTs we ever saw. I would love to do a test in a well controlled enviroment to put the argument to rest, but I don't have a 9" CRT to test with handy.

But CRT projectors also had HORRIBLE ANSI contrast and a long laundry list of other issues. Yes they absolutely did some things well, but compare that list to what digitals bring to the table and honestly there is no comparison.

Senior Video Editor
Secrets of Home Theater and High Fidelity


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Kris Deering is online now  
post #51 of 60 Old 07-29-2014, 10:25 AM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
I recently spent a weekend at Cliffy's watching his stacked G90 set up. And I wanted to and did watch a lot. Normally at HT meets I watch a bit but I am not drawn to watch a lot. The stacked pair of CRTs threw a great engaging image and I kept thinking how black the blacks were even with the black ref value doubled because of the stack, I think digitals have a way to go yet The picture on the CRTs is clearly dimmer and CRT projectors really have poor ANSI contrast.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536

Last edited by mark haflich; 07-30-2014 at 06:58 AM.
mark haflich is offline  
post #52 of 60 Old 07-29-2014, 03:49 PM
AVS Addicted Member
 
DavidHir's Avatar
 
Join Date: Dec 2004
Posts: 10,384
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 153 Post(s)
Liked: 423
Sounds pretty cool, Mark. I remember all of the "work" required just to maintain my CRT RPTVs optimally. I don't miss it all. I imagine a CRT FP requires more. I do recall how deep the blacks were - deeper than any other display tech I've owned, however, that was the only real advantage.

DavidHir is online now  
post #53 of 60 Old 07-29-2014, 05:23 PM
AVS Special Member
 
blee0120's Avatar
 
Join Date: Oct 2009
Location: Merillville, IN 46410
Posts: 3,637
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 65 Post(s)
Liked: 67
Quote:
Originally Posted by mark haflich View Post
I recently spent a weekend watching cliffy's stacked G90 set up. And I wanted to and did watch a lot. normally at HT meets I watch a bit but I am not drawn to watch a lot. The stacked pair of CRTs through a great engaging image and I kept thinking how black the blacks were even with the black ref value doubled because of the stack, I think digitals have a way to go yet The picture is clearly dimmer and CRT projectors really have poor ANSI.

Cliff always make me watch a lot. The contrast is great.
blee0120 is online now  
post #54 of 60 Old 07-29-2014, 07:21 PM
AVS Special Member
 
Ericglo's Avatar
 
Join Date: Oct 2004
Location: Just below the US in South Florida
Posts: 6,261
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Liked: 42
Kris,
IIRC Darin measured Steve Smith's G70 at around 700k to 1. I believe Steve was using gamma correction on the pj. The next time you see Darin ask him what instrument he was using if you don't know.

In your review of the DI JVC, I think you measured 300k to 400k to 1. I would say digital has pretty much matched CRT. Maybe Mark can get a loaner JVC for the CRT meet in Oct to do an actual A/B.


Mark,
You changed your reply. I know you said CRTs have higher ANSI. Admit it, you want to pull your MP 9500 out of storage and set it up.


Blee,
Was that your digital that Cliff had at the so-called last meet ever?

My new favorite game is Stop the Bots
Ericglo is offline  
post #55 of 60 Old 07-29-2014, 08:09 PM
AVS Special Member
 
Seegs108's Avatar
 
Join Date: Jul 2007
Location: Schenectady, New York
Posts: 4,083
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 222
Remember though that the JVC is dynamic contrast whereas the CRT is native contrast.
Seegs108 is offline  
post #56 of 60 Old 07-29-2014, 08:20 PM
AVS Special Member
 
blee0120's Avatar
 
Join Date: Oct 2009
Location: Merillville, IN 46410
Posts: 3,637
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 65 Post(s)
Liked: 67
Quote:
Originally Posted by Ericglo View Post
Kris,
IIRC Darin measured Steve Smith's G70 at around 700k to 1. I believe Steve was using gamma correction on the pj. The next time you see Darin ask him what instrument he was using if you don't know.

In your review of the DI JVC, I think you measured 300k to 400k to 1. I would say digital has pretty much matched CRT. Maybe Mark can get a loaner JVC for the CRT meet in Oct to do an actual A/B.


Mark,
You changed your reply. I know you said CRTs have higher ANSI. Admit it, you want to pull your MP 9500 out of storage and set it up.


Blee,
Was that your digital that Cliff had at the so-called last meet ever?
yep, I forget how many people I let borrow my DP LED. I always let the close members test it out. I don't mind, its an LED projector
blee0120 is online now  
post #57 of 60 Old 07-30-2014, 06:12 AM
AVS Club Gold
 
AV Science Sales 5's Avatar
 
Join Date: Sep 2011
Location: A beautiful view of a lake
Posts: 7,548
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 277 Post(s)
Liked: 402
Quote:
Originally Posted by blee0120 View Post
yep, I forget how many people I let borrow my DP LED. I always let the close members test it out. I don't mind, its an LED projector
This made me laugh, because when I had the demo Cine 1000 LED here, a guy asked me how many hours were on it. I told him I would have to check, but that I was sure that it was less than 100. Then I asked him if if he needed the exact number, since I did not think that really mattered if it had 1 or 100 hours on it.

Mike Garrett, AV Science Sales Call Me: 585-671-2968
Email Me:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Brands we sell: 
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
 
Call for B-stock projectors
Stewart, Seymour, SE, SI, Falcon & many more.
RBH, Martin Logan, Triad, Atlantic Technology, MK Sound, BG Radia, SVS & Def Tech.
AV Science Sales 5 is online now  
post #58 of 60 Old 07-30-2014, 07:12 AM
AVS Addicted Member
 
mark haflich's Avatar
 
Join Date: Dec 2000
Location: brookeville, maryland, usa
Posts: 19,821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked: 442
We did use a JVC years ago at one of Cliffy's meets. Its was maybe 4 or 5 years ago.

We watched it for hours though I didn't watch it much.

The bottom line is if you want to watch rather than critically pick about, just about any projector out there that we talk about in the middle boys forum, throws, OK for all you whatever (insert your own insult) out there, an AMAZING picture. Actually it is amazing that the various projection technologies actually work and throw such nice pictures. Good rooms help make the dimmer projectors appear brighter to your eyes too. Its all good. Its just there is always better.

At meets we talk a lot, we drink alot, we eat a lot, and if the weather permits we smoke cigars outside (or at least I do). The food is really good and so is the booze and beer. Sometimes one just wants to chill out and watch the cream reunion concert from start to finish only interrupted by someone like Cliffy yelling, look at them blacks.
ajvandenb likes this.

Mark Haflich

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

call me at: 240 876 2536

Last edited by mark haflich; 07-31-2014 at 04:36 AM.
mark haflich is offline  
post #59 of 60 Old 07-30-2014, 09:31 AM
Senior Member
 
ajvandenb's Avatar
 
Join Date: Oct 2008
Posts: 340
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 11
Quote:
Originally Posted by mark haflich View Post

the bottom line is if you want to watch rather than critically pick about, just about any projector out there that we talk about in the middle boys forum, throws, ok for all you whatever (insert your own insult) out there, an amazing picture. Actually it is amazing that the various projection technologies actually work and throw such nice pictures. Good rooms help make the dimmer projectors appear brighter to your eyes too. Its all good. Its just there is always better.
This!!
ajvandenb is online now  
post #60 of 60 Old 07-30-2014, 08:42 PM
AVS Special Member
 
Ericglo's Avatar
 
Join Date: Oct 2004
Location: Just below the US in South Florida
Posts: 6,261
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Liked: 42
Meets are fun till someone starts posting pictures.

My new favorite game is Stop the Bots
Ericglo is offline  
Reply Digital Hi-End Projectors - $3,000+ USD MSRP

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off