Understand Contrast with JVC RS500 - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 66 Old 01-02-2016, 08:04 PM - Thread Starter
 
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Understand Contrast with JVC RS500

I'm coming for Sony VPL600ES and switching to JVC RS500. I should be getting my unit in three days (can't wait). One of the main reason I'm switching to JVC is to get the best contrast I can since JVC can now produce even more Lumens than Sony 600ES. The goal of this thread is to understand for me (and others as well) what is the best way one can achieve the contrast. I understand that the best settings for me will not be applicable to all other but the knowing why its best for me will help me and others understand what to do to get the best contrast out of this projector while getting a bright image.

My HT: I have a dedicated home theater room. I pained it black first and then covered all the walls/ceiling/floor with black velvet. There is no window or any source that can produce any light. The only light that is produced is from projector. I'm using a 145" 2.40 screen with a 1.0 gain.

So back to contrast. As I understand, there is On/Off contrast and ANSI contrast. On/Off is what defines when we go from bright to dark scenes. ANSI is the contrast we see with bright/dark light mixed in ( like building with bright lights at night time). ANSI contrast brings more pop to the image as well.

As I understand, to get the best on/off, Iris should be as close to -15 as possible (say -13). But if iris is around -6, it will produce better ANSI contrast. If all this is correct then it seems like that I can only achieve one of the two. But then there is dual Auto Iris with RS500. In my case with 145" screen and 1.0, I think I'll be able to get a good bright image when Iris is around -5 and low lamp. If I put the lamp in high mode, chances are that I"ll be able to close iris to -10 (speculation). It is also my understanding that changing lamp mode doesn't effect the contrast.

My confusion is that if I reduce the iris, I loose ANSI contrast which brings the pop in the image that I don't want to loose and if I bring the iris to around -5, I loose on/off contrast. Is that correct? So what would you recommend? Would it be better to go for high iris setting at around -5/-6 and then let Dynamic Iris bring deep on/off contrast? Any answer that should give the best result, please explain the reason behind it.

Also, can someone please explain what dual iris is in RS500/600? Is it the function where we manually set iris to a value (say -7) and then enable Auto 1 or Auto2. Then Dynamic iris will not go below -7 and will function b/w -7 and -15 (and even lower).

I"ll mention some names here to get their attention and hope that they will jump in to share their knowledge . Others please feel free to join.

@Seegs108 , @darinp2 , @Deja Vu , @Manni01 , @R Harkness

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post #2 of 66 Old 01-02-2016, 09:19 PM
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I would not get too concerned about ANSI and offn contrast measurements. Each room has a different environment and you adjust the projector for that environment. I have a JVC RS-57U in a dark room, front is black and the rest of it is medium or dark greys. I had the JVC calibrated and settled on -5 on the iris with AUTO2 for the dynamic contrast. i have a 1.0 gain Stewart Studiotek screen. I get 16 fl off the screen at that setting with low lamp mode and max out at 20 fl with the iris set to 0. In high lamp mode I can get 30 fl which is way to bright for me... I prefer the light output to be around 14-16 fl, similar to a movie theater. I understand the standard for light levels for new calibrations is supposedly to be 40-50fl.

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post #3 of 66 Old 01-03-2016, 07:13 AM
 
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The drop in ANSI contrast is not particularly large. The theory is that when a projector uses an iris in the lens you create more light scatter within the light engine the more you close the iris down. There's simply more light hitting the back of the iris (more surface area than before) the further you close it down and this sends more light back into the light engine scattering over the imager's surface. But again, this loss is not really large enough to worry. This is especially so when you take into account the massive boost in on/off contrast you gain by closing down on the iris.

The RS500 and RS600 have two irises in them. The first one, like in the RS400 as well, is inside the lens. The second is in front of the lamp and closes down a step for every other setting you choose in the menu system. Here's what it looks like:

Open:


Closed:


Here's the lens iris:

Open:


Partially Closed:


Even Further Closed:


When you set a manual position for irises and then switch to an auto mode the iris in the lens will never open dynamically past the manually set point.

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post #4 of 66 Old 01-03-2016, 07:59 AM - Thread Starter
 
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Originally Posted by Jon S View Post
I would not get too concerned about ANSI and offn contrast measurements. Each room has a different environment and you adjust the projector for that environment. I have a JVC RS-57U in a dark room, front is black and the rest of it is medium or dark greys. I had the JVC calibrated and settled on -5 on the iris with AUTO2 for the dynamic contrast. i have a 1.0 gain Stewart Studiotek screen. I get 16 fl off the screen at that setting with low lamp mode and max out at 20 fl with the iris set to 0. In high lamp mode I can get 30 fl which is way to bright for me... I prefer the light output to be around 14-16 fl, similar to a movie theater. I understand the standard for light levels for new calibrations is supposedly to be 40-50fl.
I agree that each room has a different environment and will need to be adjusted accordingly. My question is more towards why one would pick one setting over the other. For example, let's assume that I will be ok with 16 FTL. Based on the screen size and environment, I can get 16FT in low lamp by having iris at -5 or in high lamp with iris at -10. Now which is better to use assuming Lamp long life is not a concern at all?
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post #5 of 66 Old 01-03-2016, 08:08 AM - Thread Starter
 
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Originally Posted by Seegs108 View Post
The drop in ANSI contrast is not particularly large. The theory is that when a projector uses an iris in the lens you create more light scatter within the light engine the more you close the iris down. There's simply more light hitting the back of the iris (more surface area than before) the further you close it down and this sends more light back into the light engine scattering over the imager's surface. But again, this loss is not really large enough to worry. This is especially so when you take into account the massive boost in on/off contrast you gain by closing down on the iris.

The RS500 and RS600 have two irises in them. The first one, like in the RS400 as well, is inside the lens. The second is in front of the lamp and closes down a step for every other setting you choose in the menu system. Here's what it looks like:

When you set a manual position for irises and then switch to an auto mode the iris in the lens will never open dynamically past the manually set point.
That is very interesting. So the more we close the iris, the more light will scatter within the light engine. Is this the very reason we have 2nd iris in new high end models? If not then what is the 2nd iris doing? I'm sure it is blocking the light just like 1st iris but is it placed before the light engine to reduce the light even before it gets to the 1st iris to reduce the light scattering?

You mentioned that the drop in ANIS contrast is not that large. Does that mean that if one has an option to get more on/off vs more ANSI contrast, go with on/off? I'll use the same example I mentioned before. Say if I can get the desired brightness in low lamp with iris at -5 VS in high lamp with iris at -10, which one should I be using and why? I'm trying to understand what benefits/drawbacks one has over the other (ignoring lamp life)?
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post #6 of 66 Old 01-03-2016, 08:11 AM
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Originally Posted by SherazNJ View Post
I agree that each room has a different environment and will need to be adjusted accordingly. My question is more towards why one would pick one setting over the other. For example, let's assume that I will be ok with 16 FTL. Based on the screen size and environment, I can get 16FT in low lamp by having iris at -5 or in high lamp with iris at -10. Now which is better to use assuming Lamp long life is not a concern at all?
High lamp should allow for a greater contrast ratio as it allows you to close down the iris even further in order to get the same ftL you'd get in low lamp.
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post #7 of 66 Old 01-03-2016, 08:19 AM
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Firstly there aren't "two kinds" of contrast. There are two common kinds of measurements, ANSI and On/Off, each made in with a particular set of conditions. Those two measurements provide clues to contrast performance for real world content, but only that, clues. Contrast performance is incredibly complicated and no single measurement, no two measurements come even close to describing what a given projector will look like.

That said, On/Off (Native, Sequential) contrast probably provides a better metric for most real world content than ANSI. The ANSI test pattern has an Average Picture Level of 50%, which is far, far higher than normal movie content. Soulnight has done a great job with illustrating some of this:
http://projectiondream.com/en/review...y-vpl-vw520es/


Most movie content is far below 50% Luminance.

Back to contrast, it's a continuum:


Actually it's more complicated than that even, it's the distribution of brightness is at least as important the average brightness.

Getting back to the question, to build off what others have said. Don't worry about ANSI on your JVC* no setting you make on the projector is going to affect it in a meaningful/visible way. IMO the most important considerations are lamp life (cost), noise, and getting the most contrast you can. IMO the increase in contrast you would get by running in high lamp with the iris closed further would not outweigh the negatives of more noise an higher lamp usage.

*The best way to improve ANSI contrast is to work on your room. The single biggest contributor to ANSI contrast performance is the room, blacking out even a small part of your room will have an impact several orders of magnitude more on ANSI contrast than any setting you change in the projector.
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post #8 of 66 Old 01-03-2016, 09:57 AM
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Originally Posted by SherazNJ View Post
I agree that each room has a different environment and will need to be adjusted accordingly. My question is more towards why one would pick one setting over the other. For example, let's assume that I will be ok with 16 FTL. Based on the screen size and environment, I can get 16FT in low lamp by having iris at -5 or in high lamp with iris at -10. Now which is better to use assuming Lamp long life is not a concern at all?
Why would one use high lamp mode? It shortens the life of the lamp. It also generates more heat and heat is always a problem. I have read that owners of earlier generations of JVC projectors who ran their JVCs in high lamp mode had the D-ILA panels degrade a bit faster (the panels shift colors and/or the color saturation is reduced). My old JVC RS-1, while still running, had some color saturation loss after 4,000 hours of use after eight years.

I work in a large company and we take care of numerous LCD projectors. A lot of them run in high power mode and after a couple of years, the image would degrade significantly. The image would shift to green cast and lose contrast. The ones we run in low power mode in smaller conference rooms last noticeably longer. We have bought Epson, Sony and Hitachi projectors and they all exhibit the same problems when running in high power modes.
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post #9 of 66 Old 01-03-2016, 12:05 PM - Thread Starter
 
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Originally Posted by stanger89 View Post
Getting back to the question, to build off what others have said. Don't worry about ANSI on your JVC* no setting you make on the projector is going to affect it in a meaningful/visible way. IMO the most important considerations are lamp life (cost), noise, and getting the most contrast you can. IMO the increase in contrast you would get by running in high lamp with the iris closed further would not outweigh the negatives of more noise an higher lamp usage.

*The best way to improve ANSI contrast is to work on your room. The single biggest contributor to ANSI contrast performance is the room, blacking out even a small part of your room will have an impact several orders of magnitude more on ANSI contrast than any setting you change in the projector.
Are you referring to the projector noise in high lamp or the noise is image due to lamp being in high mode? If its the projector making noise, I think I might be ok since I had no issue running Sony 600ES in high mode. Projector is mounted around 5 1/2 feet behind MLP and therefore, once the movie starts, it disappears (at least it did with Sony).

As for room, I think I did all I could. All the walls/ceiling/floor is covered with Black Velvet. When I was watching with Sony, the only thing visible was the screen.

As you mentioned that the most important is cost of lamp, noise, and getting the most contrast I can. Cost isn't important to me. Noise might not be an issue. For getting most contrast, you mentioned that room plays the most important role. I have taken care of that already.


So it seems like from all the comments, one should try to get more on/off contrast as compared to ANSI because ANSI ratio is not 100% applicable to watching movie. To increase on/off, best is to keep iris on lower side. If this requires high lamp and cost/noise is not an issue then its the way to go.

Did I get it right.
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post #10 of 66 Old 01-03-2016, 12:14 PM - Thread Starter
 
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Why would one use high lamp mode? It shortens the life of the lamp. It also generates more heat and heat is always a problem. I have read that owners of earlier generations of JVC projectors who ran their JVCs in high lamp mode had the D-ILA panels degrade a bit faster (the panels shift colors and/or the color saturation is reduced). My old JVC RS-1, while still running, had some color saturation loss after 4,000 hours of use after eight years.

I work in a large company and we take care of numerous LCD projectors. A lot of them run in high power mode and after a couple of years, the image would degrade significantly. The image would shift to green cast and lose contrast. The ones we run in low power mode in smaller conference rooms last noticeably longer. We have bought Epson, Sony and Hitachi projectors and they all exhibit the same problems when running in high power modes.
One might have to use high lamp because of big screen. Running in high does shortens the life but I made it clear that cost of lamp is not an issue. If I buy an expensive projector (over 5K) and then don't use high lamp even if I needed to just so I can save a couple of hundred dollars doesn't make much sense to me. I might get bright enough picture in low lamp but I"m very sure that I'll have to bring Iris to around -5. This will bring on/off contrast ratio reasonably down.

Unless you or others think that one can't notice contrast difference with iris at -5 VS -10, then sure I won't mind running in low lamp with iris at -5. But if I'm loosing a lot of contrast then I'd rather run in high lamp.

Your point about image degradation and shifting of color, wouldn't calibration take care of it?
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post #11 of 66 Old 01-03-2016, 12:47 PM
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Originally Posted by SherazNJ View Post
One might have to use high lamp because of big screen. Running in high does shortens the life but I made it clear that cost of lamp is not an issue. If I buy an expensive projector (over 5K) and then don't use high lamp even if I needed to just so I can save a couple of hundred dollars doesn't make much sense to me. I might get bright enough picture in low lamp but I"m very sure that I'll have to bring Iris to around -5. This will bring on/off contrast ratio reasonably down.

Unless you or others think that one can't notice contrast difference with iris at -5 VS -10, then sure I won't mind running in low lamp with iris at -5. But if I'm loosing a lot of contrast then I'd rather run in high lamp.

Your point about image degradation and shifting of color, wouldn't calibration take care of it?
When the panels degrade, nothing will correct it... You will have to replace the D-ILA panels.
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post #12 of 66 Old 01-03-2016, 01:04 PM - Thread Starter
 
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When the panels degrade, nothing will correct it... You will have to replace the D-ILA panels.
I hope that's not the case with the new ones but we won't know anytime soon. But yeah something to keep in mind that running in high mode can cause issues with panels over a few years of time frame.
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post #13 of 66 Old 01-03-2016, 01:34 PM
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Are you referring to the projector noise in high lamp or the noise is image due to lamp being in high mode? If its the projector making noise, I think I might be ok since I had no issue running Sony 600ES in high mode. Projector is mounted around 5 1/2 feet behind MLP and therefore, once the movie starts, it disappears (at least it did with Sony).
I'm referring to projector noise (audible). You might say that now, but when you're faced with the choice of running it in the "loud" mode, vs the "quiet" mode, I think most would choose quiet. It's not about whether the noise is an issue or not, most HT projectors are quiet enough that, as you say, they disappear once the movie starts, the issue is if you want to run it in the louder mode or not. And even though high lamp is quite quiet compared to other projectors, on the JVCs (I'm going off my RS4910 experience here) low is all but silent which is very nice when you hit those quiet passages.

Quote:
As you mentioned that the most important is cost of lamp, noise, and getting the most contrast I can. Cost isn't important to me. Noise might not be an issue. For getting most contrast, you mentioned that room plays the most important role. I have taken care of that already.
Then you're 99.9% of the way there. Frankly the contrast advantage/difference between settings is largely theoretical. I'm of the camp, based on my experience, that you need order of magnitude differences in contrast for it to be "noticeable". By noticeable I mean not requiring side by side/split screen comparisons to identify it. My Planar 8150 (15,000:1 dynamic, ~2500:1 native) is noticeably different contrast wise than my RS4910 (~300,000:1+ dynamic, 35,000:1 native), but I can't say I've ever really noticed any contrast difference by changing settings on my JVC (other than enabling the DI makes a difference, ah ha! order of magnitude ).

Quote:
So it seems like from all the comments, one should try to get more on/off contrast as compared to ANSI because ANSI ratio is not 100% applicable to watching movie. To increase on/off, best is to keep iris on lower side. If this requires high lamp and cost/noise is not an issue then its the way to go.

Did I get it right.
I guess what I'm getting at is, it's good to consider your setup, consider throw, and lamp mode etc, and just not worry about contrast. You've made your choice in projector, and treated your room, that's 99.9% of the equation. Anything else you do/change, any settings are unlikely to make any sort of visible difference (outside of enabling the DI or not). The difference in noise between high and low lamp will be much more noticeable than the difference between -5 and -10 on the iris.

Further you'll get greater dynamic contrast (lower absolute black floor for fade to blacks) with the iris at -5 than -10. If low lamp produces enough brightness, I'd just run that, and save high lamp for 3D or when the lamp ages.
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...

*The best way to improve ANSI contrast is to work on your room. The single biggest contributor to ANSI contrast performance is the room, blacking out even a small part of your room will have an impact several orders of magnitude more on ANSI contrast than any setting you change in the projector.
First, thanks for your reference to this article and the related AVS contrast thread. It was very informative.

One thing missing from that article though. A projector needs to do well for all scenes bright, medium and dark. Even if it's a rare occurrence, we will complain when a scene looks poor.

Second, by orders of magnitude, do you mean by factors of 10, or 2?
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I'm referring to projector noise (audible). You might say that now, but when you're faced with the choice of running it in the "loud" mode, vs the "quiet" mode, I think most would choose quiet. It's not about whether the noise is an issue or not, most HT projectors are quiet enough that, as you say, they disappear once the movie starts, the issue is if you want to run it in the louder mode or not. And even though high lamp is quite quiet compared to other projectors, on the JVCs (I'm going off my RS4910 experience here) low is all but silent which is very nice when you hit those quiet passages.



Then you're 99.9% of the way there. Frankly the contrast advantage/difference between settings is largely theoretical. I'm of the camp, based on my experience, that you need order of magnitude differences in contrast for it to be "noticeable". By noticeable I mean not requiring side by side/split screen comparisons to identify it. My Planar 8150 (15,000:1 dynamic, ~2500:1 native) is noticeably different contrast wise than my RS4910 (~300,000:1+ dynamic, 35,000:1 native), but I can't say I've ever really noticed any contrast difference by changing settings on my JVC (other than enabling the DI makes a difference, ah ha! order of magnitude ).



I guess what I'm getting at is, it's good to consider your setup, consider throw, and lamp mode etc, and just not worry about contrast. You've made your choice in projector, and treated your room, that's 99.9% of the equation. Anything else you do/change, any settings are unlikely to make any sort of visible difference (outside of enabling the DI or not). The difference in noise between high and low lamp will be much more noticeable than the difference between -5 and -10 on the iris.

Further you'll get greater dynamic contrast (lower absolute black floor for fade to blacks) with the iris at -5 than -10. If low lamp produces enough brightness, I'd just run that, and save high lamp for 3D or when the lamp ages.
Thx stanger, very informative post.
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I concur with Stranger89. His advice to run the unit in low lamp and adjusting the iris from there is what I plan on doing. It makes the most sense considering how bright these units actually are. Save high lamp for 3D mode or for when the lamp starts to age. Personally speaking, I don't think there's any risk in running the lamp in high mode in terms of panel degradation. If you only plan on using this unit for a few years I highly doubt you'll put enough hours on it that you'll see any panel degradation. I've seen no such evidence presented yet that would indicate otherwise (unlike with Sony's units). If anything, JVC used to have issues with the glue in their optical blocks breaking down overtime due to heat causing vertical stripes seen within the image on the sides. That seems to have been fixed a number or years ago.
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Just FYI, the drop in ANSI contrast between iris fully closed (min ANSI, max on/off) and iris fully open (max ANSI, min on/off) is about 20%.

I personally use low lamp, and clamp the iris to get 50-55cd/m2 fully calibrated. I use the DI on Auto2 to get the best dynamic on/off and whatever ANSI contrast I get. If you can't stand the DI artifacts, just switch it off (the DI, not the PJ). I find the benefit on fade to black and in low APL scenes worth the slight occasional instability, especially with the iris closed at least to -10.

Then, as the lamp ages, I open the manual iris to keep 50-55cd/m2, and I have the satisfaction of knowing that while my native on/off decreases, my dynamic on/off and my ANSI contrast increase. Feels really good

When the DI artifacts become too visible (I'm at -10 right now after 1290 hours in a bit less than a year and they still very acceptable), I'll replace the bulb (or the PJ).

My advice is to do the same and just enjoy your PJ...
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post #18 of 66 Old 01-03-2016, 05:04 PM
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One thing missing from that article though. A projector needs to do well for all scenes bright, medium and dark. Even if it's a rare occurrence, we will complain when a scene looks poor.
This is true. The amount it takes to pass the satisfactory level changes though. I'm not saying I would be happy if every scene had 30:1 intra-image CR, but here is a take from Bill Cushman from a while back that I think makes a good point about how much on/off CR it takes to never go below a certain intra-image CR threshold, while low ANSI CR is generally causing intra-image values with the kind of image makeup where human vision is limited for seeing intra-image CR:

http://www.widescreenreview.com/news...p?title=cineza
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Contrast Requirements For Excellent Image Quality

Two methods are commonly used for measurements of display contrast, on-off contrast ratio and ANSI checkerboard contrast ratio. CRT displays can have almost infinite on-off contrast ratio but have relatively poor ANSI contrast ratio, often measuring as low as 25:1. It has been known for years that an image with contrast of 30:1 looks quite pleasing to most people. This is very difficult to achieve on fixed pixel devices with images that have low brightness, unless the on-off contrast ratio is extremely high. The video signal is non-linear, and luminance (scene brightness) is equal to the video signal level raised to the power of gamma (usually 2.2). At medium video levels of 50, 40, and 30 percent, the corresponding brightness is 22, 13, and 7 percent. But at 20 percent video level, brightness is only 3 percent, and at 10 percent video level, brightness is an extremely low 0.6 percent. Therefore, achieving 30:1 image contrast in dark scenes requires a high on-off contrast ratio. At 20 percent video level, the required on-off contrast ratio is 1000:1, and at 10 percent video level 5000:1 is required. A 2000:1 on-off contrast ratio translates to a 12:1 image contrast ratio with a 10 percent video level. Therefore, while 2000:1 looks good in most dark scenes, it still lacks contrast and looks washed out in the very darkest scenes.

It would be great to have 100:1 image contrast at 10 percent video levels, which requires an on-off contrast ratio of 16700:1. A more realistic ideal would be 10000:1, which would give 60:1 image contrast at 10 percent video level. The same contrast requirements apply to bright scenes. Air-coupled 7-inch CRT projectors often have ANSI contrast of 30:1, whereas liquid coupled 9-inch CRT projectors sometimes achieve 100:1. Almost any LCD projector can achieve an ANSI contrast of 100:1, and DLP projectors easily achieve over 200:1. ANSI contrast is very room-color-dependent, and only rooms with dark walls will allow ANSI contrast exceeding 50:1. All of this technical talk means that virtually all projectors have satisfying contrast on bright images, but the best fixed pixel projectors will look somewhat superior in bright scenes if the viewing room has really dark walls, preferably flat black. This is the only way to achieve well over 100:1 image contrast at the screen, when showing a really bright image. To repeat what was said earlier, 30:1 image contrast looks satisfying to most people, so in summary, most projectors look great on bright images in rooms with moderately dark walls, but an on-off contrast ratio approaching 5000:1 is required for optimum results in the darkest scenes.
--Darin
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Originally Posted by Seegs108 View Post
I concur with Stranger89. His advice to run the unit in low lamp and adjusting the iris from there is what I plan on doing. .
What screen size/gain are you using?

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Originally Posted by Manni01 View Post
Just FYI, the drop in ANSI contrast between iris fully closed (min ANSI, max on/off) and iris fully open (max ANSI, min on/off) is about 20%.

I personally use low lamp, and clamp the iris to get 50-55cd/m2 fully calibrated. I use the DI on Auto2 to get the best dynamic on/off and whatever ANSI contrast I get. If you can't stand the DI artifacts, just switch it off (the DI, not the PJ). I find the benefit on fade to black and in low APL scenes worth the slight occasional instability, especially with the iris closed at least to -10.
Can you please provide 50-55/m2 in FTL?
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post #20 of 66 Old 01-03-2016, 06:12 PM
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One thing missing from that article though. A projector needs to do well for all scenes bright, medium and dark. Even if it's a rare occurrence, we will complain when a scene looks poor.
While true, it's somewhat irrelevant. I don't think there's any "high end" projector that looks remotely poor with bright scenes these days. The highest end DLPs can have ANSI contrast 3-4 times that of some LCoS machines yet bright scenes look remarkably similar (at least my Planar 8150 vs my RS4910).

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Second, by orders of magnitude, do you mean by factors of 10, or 2?
https://en.wikipedia.org/wiki/Order_of_magnitude
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post #21 of 66 Old 01-03-2016, 07:06 PM
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Originally Posted by Jon S View Post
Why would one use high lamp mode? It shortens the life of the lamp. It also generates more heat and heat is always a problem. I have read that owners of earlier generations of JVC projectors who ran their JVCs in high lamp mode had the D-ILA panels degrade a bit faster (the panels shift colors and/or the color saturation is reduced). My old JVC RS-1, while still running, had some color saturation loss after 4,000 hours of use after eight years.

I work in a large company and we take care of numerous LCD projectors. A lot of them run in high power mode and after a couple of years, the image would degrade significantly. The image would shift to green cast and lose contrast. The ones we run in low power mode in smaller conference rooms last noticeably longer. We have bought Epson, Sony and Hitachi projectors and they all exhibit the same problems when running in high power modes.
Conference projectors in a large company probably get more use than a home theater. And, for me, heat is not a problem. The projection room is well ventilated. I paid for a bright, high contrast picture and I'm not going to dial back either of those to save a few dollars on a bulb. Contrast and brightness are at odds with each other and you just make them more at odds by turning the lamp down.

If you have a HP screen, I can see using low lamp (you probably have to). But for a largish (above 120") 1.0 to 1.3 gain screen I'd want all the JVC has to offer.
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Originally Posted by stanger89 View Post



After reading and understand the graph, I can clearly see how much a room can impact the contrast. Plus this graph for contrast shows how much of contrast is measured (in different conditions) and how much of contrast one ends up getting at different levels. This (based on my understanding) is far better way to show the contrast as compared to only ANSI or On/Off ratios. Clearly there is hardly any material with 50% and therefore this ANSI at 50% is not applicable in most cases. First graph clearly shows that its mostly 20% and below.

It would be great if someone can do the same for RS500.

Last edited by SherazNJ; 01-04-2016 at 10:14 AM.
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Along this same line of thinking, the new JVC's are inky black and much brighter. It is my understanding that the nearest throw distance will give the brightest picture and the farthest gives the best contrast. You would think the middle throw distance would be the best location for brightness and contrast, but I have read where this in not the case. Of course, if you have a large screen, it would be advantageous to have the projector mounted closer and a bat cave might benefit from the farthest location. I have a 120" screen, 1.1 gain (.95 actual) and a dark room, but not a bat cave (and no new projector as yet). Is this just a matter of preference, or could someone with more experience comment on what range the throw distance is best for the newer JVC's .
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post #24 of 66 Old 01-04-2016, 10:22 AM
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Originally Posted by SherazNJ View Post
What screen size/gain are you using?



Can you please provide 50-55/m2 in FTL?
88" diag 16/9 Carada BW (effective gain around 1.1).


50cd/m2 (or nits) is roughly 14fL.
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post #25 of 66 Old 01-04-2016, 01:04 PM
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Question. I like running low lamp as well but, won't we have to run in high lamp mode for HDR on the new UHD Blu-Ray discs? I suppose it still comes down to screen sizes & gains but, I'm thinking yes.
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post #26 of 66 Old 01-04-2016, 01:11 PM
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Originally Posted by SherazNJ View Post
After reading and understand the graph, I can clearly see how much a room can impact the contrast. Plus this graph for contrast shows how much of contrast is measured (in different conditions) and how much of contrast one ends up getting at different levels. This (based on my understanding) is far better way to show the contrast as compared to only ANSI or On/Off ratios. Clearly there is hardly any material with 50% and therefore this ANSI at 50% is not applicable in most cases. First graph clearly shows that its mostly 20% and below.

It would be great if someone can do the same for RS500.
Hi,

We are happy that you enjoy our contrast studies.

We have just reviewed the jvc x500 and we will provide the same graph. The jvc rs500 (x5000) is also on our list.

To respond the thread author, we did 2 times the curve above: 1 with iris fully closed, one with irus fully opened.

The contrast curve with the iris fully opened is higher starting from 1%white upwards than with the iris closed.

Cheers,

Anna&Flo

Ps: also: ansi contrast still tells you something important: how good can the projector display black just next to white without some halos.

Last edited by Soulnight; 01-04-2016 at 01:14 PM.
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post #27 of 66 Old 01-04-2016, 02:46 PM
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Originally Posted by SherazNJ View Post
After reading and understand the graph, I can clearly see how much a room can impact the contrast. Plus this graph for contrast shows how much of contrast is measured (in different conditions) and how much of contrast one ends up getting at different levels. This (based on my understanding) is far better way to show the contrast as compared to only ANSI or On/Off ratios. Clearly there is hardly any material with 50% and therefore this ANSI at 50% is not applicable in most cases. First graph clearly shows that its mostly 20% and below.
I want to point out though that this is an oversimplification, and fails to capture a good bit of "reality". (Not to take away in the least from Soulnight and his great work, it's by far the best picture we've seen to date).

What I mean is if we go back to the measurements Mark P posted (and unfortunately you can't see them since they disappeared), he had measurements from the (if memory serves) JVC RS1 and the Sharp Z20000. It was a very interesting comparison, the JVC had 2-3x the On/Off contrast and the Sharp had 2-3x the ANSI contrast. When you looked at the graph you could clearly see a point where one overtook the other. Unfortunately we don't have anything similar for newer DLPs but surely the point in the curve has moved higher in ADL. Going by the graphs for both contrast and movie APL, one would think it would be no contest, that a high On/Off projector like the JVC would crush a low On/Off projector like my Planar 8150 in all common content.

However that's not remotely the case, my planar competes very well, if not winning in almost all content. It has to be very dark scenes before the JVC starts to pull away. I'm not trying to say ANSI is more important here mind you, but I think there are important aspects to contrast that even these latest, more detailed measurements are not fully capturing.
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post #28 of 66 Old 01-04-2016, 05:50 PM - Thread Starter
 
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Originally Posted by Soulnight View Post
Hi,

We are happy that you enjoy our contrast studies.

We have just reviewed the jvc x500 and we will provide the same graph. The jvc rs500 (x5000) is also on our list.

To respond the thread author, we did 2 times the curve above: 1 with iris fully closed, one with irus fully opened.

The contrast curve with the iris fully opened is higher starting from 1%white upwards than with the iris closed.

Cheers,

Anna&Flo

Ps: also: ansi contrast still tells you something important: how good can the projector display black just next to white without some halos.
Great. Is there any ETA on when you'll publish review on RS500?
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post #29 of 66 Old 01-04-2016, 05:58 PM - Thread Starter
 
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Originally Posted by stanger89 View Post
I want to point out though that this is an oversimplification, and fails to capture a good bit of "reality". (Not to take away in the least from Soulnight and his great work, it's by far the best picture we've seen to date).

What I mean is if we go back to the measurements Mark P posted (and unfortunately you can't see them since they disappeared), he had measurements from the (if memory serves) JVC RS1 and the Sharp Z20000. It was a very interesting comparison, the JVC had 2-3x the On/Off contrast and the Sharp had 2-3x the ANSI contrast. When you looked at the graph you could clearly see a point where one overtook the other. Unfortunately we don't have anything similar for newer DLPs but surely the point in the curve has moved higher in ADL. Going by the graphs for both contrast and movie APL, one would think it would be no contest, that a high On/Off projector like the JVC would crush a low On/Off projector like my Planar 8150 in all common content.

However that's not remotely the case, my planar competes very well, if not winning in almost all content. It has to be very dark scenes before the JVC starts to pull away. I'm not trying to say ANSI is more important here mind you, but I think there are important aspects to contrast that even these latest, more detailed measurements are not fully capturing.
Thx for the info. Which model of JVC are you comparing to when you stated that Planer 8150 was competed very well? So do you think there is a way that can describe contrast such that it can be related to real world? I mean who can the buyer know what he's going to get? Before the common ground was that Specs are mostly marketing and therefore let the reviewers review and go from there. But then reviewers have their way to measuring contrast as well and if that doesn't apply to how contrast is utilized in real world then how can a regular buyer (Like me) know what they are getting and what's better than what I have?
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post #30 of 66 Old 01-04-2016, 06:16 PM
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Thx for the info. Which model of JVC are you comparing to when you stated that Planer 8150 was competed very well?
I've got an RS4910 and a Planar 8150 hanging in my HT.

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So do you think there is a way that can describe contrast such that it can be related to real world? I mean who can the buyer know what he's going to get? Before the common ground was that Specs are mostly marketing and therefore let the reviewers review and go from there. But then reviewers have their way to measuring contrast as well and if that doesn't apply to how contrast is utilized in real world then how can a regular buyer (Like me) know what they are getting and what's better than what I have?
It's possible, but I think impractical. In a way it's like RGB Gains/Offsets vs multi-point gamma, vs a 3D LUT. Except it's probably more complicated more complicated because in addition to just the values, the distribution of those values also makes a difference. Maybe what we need is MTF measured at various picture levels.

All that said, I'm not saying the reviews are wrong, just that, like always, it's important to understand what the measurements say, what they don't, along with what can be inferred and what can't.
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