JVC RS4500 (native 4K laser projector)

[Dylan Seeger]

I noticed you said you're using mode 2 for the laser dimming. Does mode 1 turn the laser off completely?

[Pultzar]

It's too bad there isn't a protocol giving the projector metadata about what is to come in say the next 30 seconds.  It could then be much smarter about how it controls its output.

[Javs]

While some like the LS10000's ability to go to absolute black, several have complained about the sudden jump in brightness when the laser comes back on. So you can either go for the absolute spec or you can go with what works the best. Of course in a perfect world, we would have both, but looks like you can't have your cake and eat it too. At least not yet.

I agree with you Mike. The LS definitely kind of punched you in the face when just one single pixel came on and the thing just suddenly sprung out of full black. But the 1% Z1 measurements look good to me, far higher than the LS probably can do. In fact checking Projection Dreams LS measurements just now, at 1% they show only 6500:1, but thats Iris open, I can assume iris in the middle positino will be 8-9k:1 at best at 1% APL in the best case scenario, the Z1 still doubles the LS 1% contrast levels and this is great.

I just don't get why then JVC spent all this time touting infinity contrast, since we all know if the laser is on at all, this is not, and never will be infinity. I always believed this was because they can and did flat out shut off the laser. So there has got to be a mode or some such to have the laser fully switch off. I would accept a very mild pump with this, I know a lot of guys differ... But since with my full fades, I am looking at at least a few hundred thousand K:1 after the dust has settled on the fade, and I can still see grey essentially, I was hoping that would be black finally.

[DavidHir]

Maybe this is JVC's philosophy though because doesn't the auto iris on the RS400-600 not close down as much as the 2014 models in an attempt to make the darkness more gradual?

[Kris Deering]

I noticed you said you're using mode 2 for the laser dimming. Does mode 1 turn the laser off completely?

No. Mode 1 is a "less aggressive" version of Mode 2. It seems to be the same overall in noticeability, but it doesn't dim down as far so you lose a bit on the blacks. This is apparent in measurements though I don't know how much you'd notice it in real world viewing.

[AVSMike]

I agree with you Mike. The LS definitely kind of punched you in the face when just one single pixel came on and the thing just suddenly sprung out of full black. But the 1% Z1 measurements look good to me, far higher than the LS probably can do. In fact checking Projection Dreams LS measurements just now, at 1% they show only 6500:1, but thats Iris open, I can assume iris in the middle positino will be 8-9k:1 at best at 1% APL in the best case scenario, the Z1 still doubles the LS 1% contrast levels and this is great.

I just don't get why then JVC spent all this time touting infinity contrast, since we all know if the laser is on at all, this is not, and never will be infinity. I always believed this was because they can and did flat out shut off the laser. So there has got to be a mode or some such to have the laser fully switch off. I would accept a very mild pump with this, I know a lot of guys differ... But since with my full fades, I am looking at at least a few hundred thousand K:1 after the dust has settled on the fade, and I can still see grey essentially, I was hoping that would be black finally.

Either that or it could quite simply be that the original dimming software did turn off the laser. JVC then saw the same problem that the Epson has and solved it by not doing full off. This is just a hypothesis.

[AVSCraig]

I agree with you Mike. The LS definitely kind of punched you in the face when just one single pixel came on and the thing just suddenly sprung out of full black. But the 1% Z1 measurements look good to me, far higher than the LS probably can do. In fact checking Projection Dreams LS measurements just now, at 1% they show only 6500:1, but thats Iris open, I can assume iris in the middle positino will be 8-9k:1 at best at 1% APL in the best case scenario, the Z1 still doubles the LS 1% contrast levels and this is great.

I just don't get why then JVC spent all this time touting infinity contrast, since we all know if the laser is on at all, this is not, and never will be infinity. I always believed this was because they can and did flat out shut off the laser. So there has got to be a mode or some such to have the laser fully switch off. I would accept a very mild pump with this, I know a lot of guys differ... But since with my full fades, I am looking at at least a few hundred thousand K:1 after the dust has settled on the fade, and I can still see grey essentially, I was hoping that would be black finally.

Seeing as this is JVC's flagship home theater projector. and it is much easier to update the firmware, maybe this will be revised and improved in the future. I'm looking forward to testing this projector myself.

[thebland]

Sounds good. At 1.3 gain on a 14' Microperf screen, how well will this PJ light things up? Any measurements, thoughts, etc. ? Is this PJ for larger screens?

Thanks for the heads up Kris (and Mike).

[AVSMike]

Sounds good. At 1.3 gain on a 14' Microperf screen, how well will this PJ light things up? Any measurements, thoughts, etc. ? Is this PJ for larger screens?

Thanks for the heads up Kris (and Mike).

Without your A-lens around 27/30FL max depending on throw, on your Ultramatte 150 microperf (1.35 gain).

[mark_h]

Unlike the Epson, it doesn't turn completely off. So you don't get that jarring off/on with fades or dark sequences but you also don't get a true infinite black.

Oh, that's a shame.  I like complete fade to black.  In a light controlled room you are plunged into absolute darkness.  Filmmakers often use this mechanic - no light, but plenty of sound - it's very effective, and it's always spoiled by light off the screen.

Will withhold final judgment until I see it for myself (hopefully next week).

[ARROW-AV]

Nonsense.

The LS10k literally shuts off at 0%. I have stared directly into the lens while it does this.

Im just confused as to why the Z1 didn't apparently do this if 0% was projected and dimming was confirmed to be on.

While some like the LS10000's ability to go to absolute black, several have complained about the sudden jump in brightness when the laser comes back on...

So not quite NONSENSE eh Javs? But don't worry, you are forgiven already

So-called 'INFINITE' contrast ratios ARE unfortunately B.S.

I can in fact make any projector I like have  'INFINITE' contrast by simply pulling out the power cable or simply covering the lens whenever an image fades to 100% black... But let me ask you this... What happens if you were to feed any such projector reporting to have 'INFINITE' contrast, like the EPSON LS10000/10500, a video signal that is not 100% black? Even, as you say, a single pixel that is not black? And so has at least some of the image being lit? Does the black level remain the same? In other words, is the portion of the image that is black the same black level as when a complete fade to black? Yes or no? Because with true 'INFINITE' contrast the answer would be YES... But the answer is not yes, is it? Consequently, simply shutting off the light source completely if or whenever there is a 100% fade to black is most certainly NOT in fact truly 'INFINITE' contrast at all, but merely a gimmick and IMO a highly annoying one too, because of the significant jumps and disproportionate changes in black level between 100% black and everything else. OK?

The LS definitely kind of punched you in the face when just one single pixel came on and the thing just suddenly sprung out of full black... I just don't get why then JVC spent all this time touting infinity contrast, since we all know if the laser is on at all, this is not, and never will be infinity. I always believed this was because they can and did flat out shut off the laser. So there has got to be a mode or some such to have the laser fully switch off. I would accept a very mild pump with this, I know a lot of guys differ... But since with my full fades, I am looking at at least a few hundred thousand K:1 after the dust has settled on the fade, and I can still see grey essentially, I was hoping that would be black finally.

Because the 'INFINITE' contrast is a fudge, and not in fact true infinite contrast at all, the projector can't do it properly. It's as simple as that. 

And typically the real reason why projector manufacturers choose to, as you say, tout infinity contrast, is because that's almost always merely a smokescreen to try to hide the fact that the projector's native contrast is not comparatively good... For example, I haven't ever seen JVC by shy about touting the superior contrast ratios of their projectors, when the contrast ratios are in fact superb, have you?

So you have only two choices, namely either have the light source shut off completely with 100% black but not everything else, or a proportionate reduction in luminosity in which case 100% black will not in fact yield zero cd/m2. Where it's a matter of personal preference, but I personally prefer the latter given IMO nothing destroys immersiveness more than an unnatural jarring with respect to the video image

That said, I don't like blacks being grey either, but I am extraordinarily fussy and so very difficult to please! 
.

[Javs]

So not quite NONSENSE eh Javs? But don't worry, you are forgiven already

So-called 'INFINITE' contrast ratios ARE unfortunately B.S.

I can in fact make any projector I like have  'INFINITE' contrast by simply pulling out the power cable or simply covering the lens whenever an image fades to 100% black... But let me ask you this... What happens if you were to feed any such projector reporting to have 'INFINITE' contrast, like the EPSON LS10000/10500, a video signal that is not 100% black? Even, as you say, a single pixel that is not black? And so has at least some of the image being lit? Does the black level remain the same? In other words, is the portion of the image that is black the same black level as when a complete fade to black? Yes or no? Because with true 'INFINITE' contrast the answer would be YES... But the answer is not yes, is it? Consequently, simply shutting off the light source completely if or whenever there is a 100% fade to black is most certainly NOT in fact truly 'INFINITE' contrast at all, but merely a gimmick and IMO a highly annoying one too, because of the significant jumps and disproportionate changes in black level between 100% black and everything else. OK?
Because the 'INFINITE' contrast is a fudge, and not in fact true infinite contrast at all, the projector can't do it properly. It's as simple as that. 

And typically the real reason why projector manufacturers choose to, as you say, tout infinity contrast, is because that's almost always merely a smokescreen to try to hide the fact that the projector's native contrast is not comparatively good... For example, I haven't ever seen JVC by shy about touting the superior contrast ratios of their projectors, when the contrast ratios are in fact superb, have you?

So you have only two choices, namely either have the light source shut off completely with 100% black but not everything else, or a proportionate reduction in luminosity in which case 100% black will not in fact yield zero cd/m2. Where it's a matter of personal preference, but I personally prefer the latter given IMO nothing destroys immersiveness more than an unnatural jarring with respect to the video image

That said, I don't like blacks being grey either, but I am extraordinarily fussy and so very difficult to please! 
.

I am not sure why you are debating this with me. I didn't invent the infinity contrast ratio metric. But I do know that the manufacturers who have claimed it until today with JVC, I am talking Sony and Epson, both are able to shut the laser off in 100% black, thus there is no black level, thus when divided into white, its ON/OFF contrast ratio is infinite.

I know you are intelligent, but no need to try and drive this point home as if I dont understand the significance, the metric is not BS. It just means JVC in this case are not delivering on it.

The simple maths is this, in ON/OFF contrast, which almost all projectors are judged and sold if the projector has NO black level, there is zero luminance, and 150 nits peak white, then the ON/OFF contrast is unable to be calculated, this its infinity. If you are going to try and argue this point with me you are going to get very tired because I wont let up.

What happens if you were to feed any such projector reporting to have 'INFINITE' contrast, like the EPSON LS10000/10500, a video signal that is not 100% black?

If the video signal is supposed to be black, and it is not, then something is not set up right, hardly the projectors fault. If you are talking about a couple of pixels, Then it is no longer ON/OFF contrast is it? It then becomes a metric of ANSI contrast, which is why I asked for the Z1's measurements at 1 through 4% since I have been saying for months, not just in the Z1 thread which seems to be the only one you frequent much, but I have been saying it for months. With laser projectors, since they seem to be able to project (or lack thereof) TRUE black, then they need to be measured on ANSI measurements starting at 1% all the way up to the recognised 50% ANSI measurement.

Because with true 'INFINITE' contrast the answer would be YES...

If they are talking about Infinity ON/OFF contrast then they would be correct and the answer would be yes, you are once again talking about ANSI contrast, please understand the difference.


So you have only two choices, namely either have the light source shut off completely with 100% black but not everything else, or a proportionate reduction in luminosity in which case 100% black will not in fact yield zero cd/m2. Where it's a matter of personal preference, but I personally prefer the latter given IMO nothing destroys immersiveness more than an unnatural jarring with respect to the video image

Why do I only have two choices? How about a projector that can do 100k:1 at 1% APL, like I am sure the RS600 does at , and true black laser OFF at 0%. That's the best of all worlds, and for folks like yourself who dont like the 0% true black, have an option to turn it off, then the machine will do 150k:1 in black...

[Peter Parker]

I like the way the Epson lasers do complete full fade to black, and I don't mind the occasional blip as it comes out of black after it does that - for me I find the pros outweigh the cons. Being unable to see even your hand in front of your face in those instances does feel uncomfortable (in a good way) when it happens and adds something to the experience. Not everyone feels that way of course, but I do feel it's an added benefit and it would be nice for the Z1 to be able to do that as well if you wanted it. I find it a better compromise than the grey image you get with all other projectors that do 'black'. Even with the JVCs and eye adaption, you're often left with some grey if the FFTB is held long enough.

Zero light for black will always give infinite contrast so is not completely BS - it's done automatically and within the film playback without any intervention so is not the same as pulling the plug, otherwise all projectors could claim infinite CR. But it's not the true CR capability of the pj natively or dynamically.

With the JVC and Epson it would be good to see what the best CR is at 0% is without the laser being shut off so that we can see the native and dynamic contrast capability of the projector, that will tell us a lot about the general contrast performance and having the laser shut off for 0% is an option if you want it. Without that, even a laser LCD with 1500:1 CR could claim infinity the same as all other laser based projectors but it wouldn't tell us anything about the contrast performance during normal content, so we need to know the native (and dynamic) CR capability.

I remember some years ago Greg Rogers talking about the contrast ratios at 16 and 17 (to 235) and have been interested in seeing those measurements from all projectors, and have asked people for those measurements in the past but have never been given them - Javs and then Kris are the first ones I've seen do this and publish that information and I think it helps to see what the CR capability of the pj is at low levels. It's not as simple as that as set up can come into play (i.e how you set up 17 on the JVC for example) and if using grey and not white, gamma can come into play, but it does give us some insight into the contrast capability of the projector. We just need to all be using the same patterns for better comparisons. C4Hs graph for on/off to ANSI is a great example, but some other people are doing it differently and not releasing those patterns so they're not comparable, only within a particular individuals reviews.

On a side note, using a generator for test patterns is said to be ideal, but that only works if the video chain that will be used is also ideal. If the chain isn't, and you calibrate to the generator so the image you get is at D65, when you start playing movies via the video chain, the image may no longer be at D65. You'll only get that when watching the generator. So you you need to check the video playback is as accurate as the generator. Of course the answer is to make sure the player/chain is reference so that the video playback is the same as the generator, but not all clients will have that, so then I would think they would get better results with reference disk in the clients equipment rather than using a generator in those instances.

[lygren]

Totally agree that adding "infinite" contrast as part of the spec just reduces overall credibility for JVC or any other producer doing the same... The Epson LS10000 hanging in my current cinema just annoys me when shutting off the laser between scenes, does not seem natural at all since the difference between "off" and "on" is such clearly noted. It´s not like the good ol´ CRTs where actually information was portrayed while keeping the remainder of the frame at practically zero...

Still, looking forward to see how the laser dimming works out for the Z1, hopefully we´ll get these monsters delivered here in Norway soon as well!

 

[AVSMike]

I am not sure why you are debating this with me. I didn't invent the infinity contrast ratio metric. But I do know that the manufacturers who have claimed it until today with JVC, I am talking Sony and Epson, both are able to shut the laser off in 100% black, thus there is no black level, thus when divided into white, its ON/OFF contrast ratio is infinite.

I know you are intelligent, but no need to try and drive this point home as if I dont understand the significance, the metric is not BS. It just means JVC in this case are not delivering on it.

The simple maths is this, in ON/OFF contrast, which almost all projectors are judged and sold if the projector has NO black level, there is zero luminance, and 150 nits peak white, then the ON/OFF contrast is unable to be calculated, this its infinity. If you are going to try and argue this point with me you are going to get very tired because I wont let up.

What happens if you were to feed any such projector reporting to have 'INFINITE' contrast, like the EPSON LS10000/10500, a video signal that is not 100% black?

If the video signal is supposed to be black, and it is not, then something is not set up right, hardly the projectors fault. If you are talking about a couple of pixels, Then it is no longer ON/OFF contrast is it? It then becomes a metric of ANSI contrast, which is why I asked for the Z1's measurements at 1 through 4% since I have been saying for months, not just in the Z1 thread which seems to be the only one you frequent much, but I have been saying it for months. With laser projectors, since they seem to be able to project (or lack thereof) TRUE black, then they need to be measured on ANSI measurements starting at 1% all the way up to the recognised 50% ANSI measurement.

Because with true 'INFINITE' contrast the answer would be YES...

If they are talking about Infinity ON/OFF contrast then they would be correct and the answer would be yes, you are once again talking about ANSI contrast, please understand the difference.


So you have only two choices, namely either have the light source shut off completely with 100% black but not everything else, or a proportionate reduction in luminosity in which case 100% black will not in fact yield zero cd/m2. Where it's a matter of personal preference, but I personally prefer the latter given IMO nothing destroys immersiveness more than an unnatural jarring with respect to the video image

Why do I only have two choices? How about a projector that can do 100k:1 at 1% APL, like I am sure the RS600 does at , and true black laser OFF at 0%. That's the best of all worlds, and for folks like yourself who dont like the 0% true black, have an option to turn it off, then the machine will do 150k:1 in black...

Has the Epson been measured at 1%? Curious to know the answer to that, to see how big of a jump it has coming out off infinity. It is probably just as easy for JVC to have set the projector up, to just turn off the light source in a full fade to black, so it sounds to me JVC selected not to, because overall it came across better when viewing. I will see if I can get any information.