JVC New Projectors Announced - CEDIA 2012 - Page 22 - AVS Forum
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post #631 of 1073 Old 09-28-2012, 04:36 PM
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Zombie, For the method Owen was describing, FFDShow uses CPU for the upscaling and sharpening, and the GPU to do the downscaling (automatically - to the display resolution).
Owen, if you have any tips on how to set this up without chewing large amounts of CPU, let us know as a few of us would like to try your method (and compare it to e-shift, projector sharpening, darby etc.).
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post #632 of 1073 Old 09-28-2012, 05:10 PM
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Quote:
Originally Posted by Owen View Post

The X70 - X90 lamp iris pictured on the cine4home.de site does not look like it is intended to be partially closed, but in any event any closing of the lamp or lens iris reduces the projectors light output in proportion the the gain in CR. The question that remains unanswered is can the RS56 deliver greater contrast than lower models while delivering equal light output. We will have to wait until tests can be conducted over a range of iris settings in comparison to single iris models before that will be known for sure.
Since the dual iris system has been around for a while now I'm surprised this issue has not been raised before.
It has been. A long time ago. Cine4home did a comprehensive review of the RS40/50/60 which included a lot of data in a chart. I plotted it in Excel and posted it in the RS50 owners thread. Here are the relevant charts:





Note:
The RS50 (X7) CR spec is: 70K:1
The RS40 (X3) CR spec is: 50K:1

But notice that under more realistic viewing conditions the typical contrast ratio difference is less than 5,000:1 and not 20,000:1 as one might believe given the specs.

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post #633 of 1073 Old 09-28-2012, 05:17 PM
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Quote:
Originally Posted by zombie10k View Post

There is no separate control for the second iris. It's an odd/even step, so each change clamps down the main iris, the next the lamp iris, etc. It all depends on your room setup to know if you can take advantage of the extra contrast. While there is a stated increase in the native contrast this year (55 @80k, 56 @ 90k) most of this does come from the iris being clamped down.
I have my RS55 very close to eye level on my 142" 2.8HP. With the lamp on high and iris cranked to -11, it's still very bright. I can close it down all the way and it still looks great. Obviously this isn't going to help if someone has a 140" AT screen and needs max lumens, so the 4810 would be a more likely choice.
I did have an RS45/55 side by side in my setup. The most obvious difference was the e-shift given the screen size / seating distance. This specific RS45 had some bizarre issues (bright corners that stood out) and some streaking of fonts/menus on high contrast scenes. It was tough to do a fair comparison. 3D performance was nearly identical though.

Thanks Jason,

That makes me know how the second iris works. I'm still debating whether to go to a RS56 vs the RS4810. Right now, I'm leaning towards the 4810 for the extra year warranty and the price difference.

Thanks again,
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post #634 of 1073 Old 09-28-2012, 05:23 PM
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Don't let the extra year warranty sway anyone for buying.
We all know we just need one year before the next JVC projector is out.smile.gif
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post #635 of 1073 Old 09-28-2012, 08:26 PM
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Quote:
Originally Posted by Geof View Post

It has been. A long time ago. Cine4home did a comprehensive review of the RS40/50/60 which included a lot of data in a chart. I plotted it in Excel and posted it in the RS50 owners thread. Here are the relevant charts:
Note:
The RS50 (X7) CR spec is: 70K:1
The RS40 (X3) CR spec is: 50K:1
But notice that under more realistic viewing conditions the typical contrast ratio difference is less than 5,000:1 and not 20,000:1 as one might believe given the specs.

So that means under more realistic conditions the typical contrast ratio difference between the RS4810 and the RS56 is actually at or less than 10,000:1 instead of the advertised 40,000:1 difference spec. (50,000:1 on RS4810 vs 90,000:1 on RS56). So can you say that realistically the RS56 has a contrast ratio of 60,000:1 ?? If so, the RS4810 is definitely the better deal.
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post #636 of 1073 Old 09-28-2012, 08:50 PM
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if you need the wide open iris for max lumens, the difference wouldn't make sense for the extra $$. Things might change @ -11 or lower. With my HP, I'll take as much advantage as I can get.

We're assuming the 3D is going to the same across all 4 models. I'm curious if there are any variances between the 3 models (RS46, 4810, 56/66).


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post #637 of 1073 Old 09-28-2012, 10:15 PM
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Quote:
Originally Posted by SED <--- Rules View Post

So that means under more realistic conditions the typical contrast ratio difference between the RS4810 and the RS56 is actually at or less than 10,000:1 instead of the advertised 40,000:1 difference spec. (50,000:1 on RS4810 vs 90,000:1 on RS56). So can you say that realistically the RS56 has a contrast ratio of 60,000:1 ?? If so, the RS4810 is definitely the better deal.

I wouldn't trust Native On/Off readings when they get this high, it's hard to measure it correctly. I base this on the fact that everyone ended up with different measurements for the JVC's. I'm not saying Cine4Home's measurements are wrong, but I'm just saying you can't know for sure.



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post #638 of 1073 Old 09-29-2012, 05:32 AM
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Quote:
Originally Posted by SED <--- Rules View Post

So that means under more realistic conditions the typical contrast ratio difference between the RS4810 and the RS56 is actually at or less than 10,000:1 instead of the advertised 40,000:1 difference spec. (50,000:1 on RS4810 vs 90,000:1 on RS56). So can you say that realistically the RS56 has a contrast ratio of 60,000:1 ?? If so, the RS4810 is definitely the better deal.
With the iris open there is less than a 5K:1 advantage to the X7 but with the iris closed there there appears to be an 8K:1 to 15K:1 advantage to the X7. So the difference one would see in their particular setup is dependent on iris setting and throw: At mid throw and the iris at -10 the typical advantage of the X7 is in the neighborhood of 14K:1. The RS56 has a higher CR then the X7 so I would expect an RS556/RS548 difference to be 20K:1 or better with typical settings. How this equates to what you see is dependent on the room and gamma settings so there is no cut and dried answer. BTW, I trust Cine4Home's measurements and even if they have an absolute error the relative error between the X3 and X7 measurements are likely non-factors when comparing the two.

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post #639 of 1073 Old 09-29-2012, 06:00 AM
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Mike G,
What does the "Specialized QC" of the RS4810 entail?

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post #640 of 1073 Old 09-29-2012, 06:45 AM
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Quote:
Originally Posted by Geof View Post

With the iris open there is less than a 5K:1 advantage to the X7 but with the iris closed there there appears to be an 8K:1 to 15K:1 advantage to the X7. So the difference one would see in their particular setup is dependent on iris setting and throw: At mid throw and the iris at -10 the typical advantage of the X7 is in the neighborhood of 14K:1. The RS56 has a higher CR then the X7 so I would expect an RS556/RS548 difference to be 20K:1 or better with typical settings. How this equates to what you see is dependent on the room and gamma settings so there is no cut and dried answer. BTW, I trust Cine4Home's measurements and even if they have an absolute error the relative error between the X3 and X7 measurements are likely non-factors when comparing the two.

Thanks for the info on the X3 and X7 Geof, I remember reading the review at cine4home back in the day but when I looked at it recently in the interests of this thread my browser would not display it properly and I could not see the table with CR and lumen results. A different browser cured that problem and after going over the CR and light output numbers for the X3 and X7 JVC's I have come to the conclusion that both have effectively the same CR at wide open and medium iris, its only when the iris system on the X7 is closed down more than half does it begin to pull ahead.
With the X7's iris system closed down fully it provides about 15% more contrast and looses about 15% light output compared to the X3. As expected additional contrast comes at the expense of brightness and that will be the case with the new models as well.

For a difference in contrast to be worth bothering with it needs to be pretty significant. An increase of 100% is only one stop and not much in light terms so less than that is not really cutting it as an upgrade IMHO. Those who want an worthwhile increase in CR over a basic JVC need to go for the top model and have enough screen gain to run with the iris system closed down.
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post #641 of 1073 Old 09-29-2012, 07:02 AM
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I pretty much agree but I do think the increased CR of the RS56 would be noticeable over the RS4810 in side by side comparisons although it may not be noticeable otherwise. I'm of the understanding that meaningful differences follow a logarithmic curve so doubling CR is still a small increase as far as the eye can tell. The difference between 32K:1 and 52K:1 sounds significant but may not look significant to the eye. I'm not sure if it's $1500 better but I guess that depends on how fat the wallet is and whether or not the viewing conditions allow one to see it.

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post #642 of 1073 Old 09-29-2012, 08:33 AM
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Quote:
Originally Posted by Geof View Post

Mike G,
What does the "Specialized QC" of the RS4810 entail?

I am sitting in the stands waiting for this at bat. smile.gif

The answer can not be within Mike's knowledge at this point.

Could you get it by asking a US JVC guy? Or need you get it from someone overseas at the factory?

It would be relatively easy for a US guy to fake an answer here. For example, we add additional QC check points on the assembly line for the 4810 over the 48. Works for me. Who could argue? Or, we turn it over and shake twice instead of once. Shaken never stirred? Yes and Like James Bond in Diamonds are For Ever, we make sure the cuffs match the collar.


There is an additional year warranty and for the consumer that is the critical thing. Considering the cost of providing an additional year and yes projectors do fail as they get older and I am pretty sure the failure rate is much greater in year 3 than say in year 2, it would financially behove a manufacture chosing to give a free extra year to try and build to avoid a third year failure, however, I doubt much could be done without part substitutions, say a bigger cooling capacity, to achieve this.

Remember, most failures occur early in a product's life. DOA etc. Third year failures are often associated with hours used, number of turn ons and turn offs, dust glogging etc. Panel degradation from heat. Sort of a big crap shoot.

Anyway. If I were going to buy a projector with only a two year warranty that I was planning on keeping for over two years, I would buy an add on warranty. Projectors fail. And when they fail out of warranty, repair bills are high very often exceeding $3K. Sometimes more than the projector cost and often more than it would be worth after the repair. Kudos for JVC in giving a 3 year warranty on the 4810.

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post #643 of 1073 Old 09-29-2012, 08:39 AM
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Quote:
Originally Posted by Geof View Post

I pretty much agree but I do think the increased CR of the RS56 would be noticeable over the RS4810 in side by side comparisons although it may not be noticeable otherwise. I'm of the understanding that meaningful differences follow a logarithmic curve so doubling CR is still a small increase as far as the eye can tell. The difference between 32K:1 and 52K:1 sounds significant but may not look significant to the eye. I'm not sure if it's $1500 better but I guess that depends on how fat the wallet is and whether or not the viewing conditions allow one to see it.

That's about the size of it, people get all worked up over CR numbers without having a clear understanding of what they mean. In my experience a 100% step up is the minimum I would pay significant cash for and that's likely more than can be obtained by going from the base model to the top of the range.

Buying an RS56 and not running it with the iris system closed down all the way seems like a pointless exercise, may as well buy a cheaper model. Even then CR will only be slightly better and at the expense brightness.

As long as people understand what they are buying its all good.
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post #644 of 1073 Old 09-29-2012, 09:18 AM
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Quote:
Originally Posted by Geof View Post

Mike G,
What does the "Specialized QC" of the RS4810 entail?

I am checking on this. Not 100% sure it is the same as last year so want to get it verified before saying anything. Once my info is verified, I will post.

Now to farther address the contrast of the dual iris system of the JVC (RS56 & RS66). Now everybody here now knows that it is a dual iris system. Both iris's are controlled by a single control, but they do not change the same. The outer iris moves several steps before the inner iris (by the lamp) moves a single step. Even when the iris “system” is only closed partially, they are both engaged, so there is less light scatter. So, you will see better contrast at any chosen brightness level.

The basic idea of brightness level is that often you have more foot lamberts than you actually need for a specific environment. The idea is not to make the picture too dark, but to close down the iris so that the brightest parts of the picture are in the correct range for your theater. lets say you are getting 22 foot lamberts off the screen with the iris fully open. So if you are getting 22fl off the screen in your peak bright spots, then by closing the iris so that you only peak at 16fl off the screen two things will happen: The brightest parts of the picture will now be in a more comfortable range with full brightness, and in the process, the darkest parts of the picture will become darker. If your system is set up so that starting off with a new lamp, you have to use the projector with the iris fully open then you either need a smaller screen, a screen with more gain, both or a brighter projector.

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post #645 of 1073 Old 09-29-2012, 09:54 AM
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Quote:
Originally Posted by Geof View Post

It has been. A long time ago. Cine4home did a comprehensive review of the RS40/50/60 which included a lot of data in a chart. I plotted it in Excel and posted it in the RS50 owners thread. Here are the relevant charts:



Note:
The RS50 (X7) CR spec is: 70K:1
The RS40 (X3) CR spec is: 50K:1
But notice that under more realistic viewing conditions the typical contrast ratio difference is less than 5,000:1 and not 20,000:1 as one might believe given the specs.

The RS50 was on the dim side. Would a brighter RS56/66 not be able to close the iris down more allowing for much higher contrast? if the dimmer RS50 could get nearly double the contrast at any zoom setting with the iris closed down, I would think the newer brighter 56/66 would do even better. Note that the starting contrast difference between the RS40 and RS70 was only 20,000. The starting difference between the RS46 and RS56 is 40,000.

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post #646 of 1073 Old 09-29-2012, 10:14 AM
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The RS50 was on the dim side. Would a brighter RS56/66 not be able to close the iris down more allowing for much higher contrast? if the dimmer RS50 could get nearly double the contrast at any zoom setting with the iris closed down, I would think the newer brighter 56/66 would do even better.

good point, the RS50 was not a light cannon if we're being polite. smile.gif The 55 was noticeably brighter than the 50. I was able to lower the iris much lower with the 55 than the 50.

I watched this excellent document on Bob Marley last night. There are intense colors and quick drops to black in this film. A real treat at -11 on the big HP.

i've run my lamp at high alt since new, it's been holding up well (rev 2 w / out flapper). -11 is still almost too bright, I went down to -13 and it's good now. If the RS56 is the same or better, i'm good with cranking the iris all the way down.


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post #647 of 1073 Old 09-29-2012, 10:18 AM
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Quote:
Originally Posted by AV Science Sales 5 View Post

The RS50 was on the dim side. Would a brighter RS56/66 not be able to close the iris down more allowing for much higher contrast? if the dimmer RS50 could get nearly double the contrast at any zoom setting with the iris closed down, I would think the newer brighter 56/66 would do even better. Note that the starting contrast difference between the RS40 and RS70 was only 20,000. The starting difference between the RS46 and RS56 is 40,000.
Well the charts I posted were relevant to the RS50 with iris wide open, partially shut and fully closed so I would expect similar CR behavior with newer dual iris machines but with more accompanying brightness. So yes, one could close the iris more to achieve a higher CR with the brighter machine. The difference between an RS48 and RS56 is 40:000:1 but if the CR behavior follows a similar patterns as the charts show I would expect the CR difference to be closer to 20K:1 then 40K:1 with a more typical setup. That said, even if the real world usable difference was 40K:1 the perceived CR increase will not be huge as Owen discusses above. In the end though the only way to know for sure is wait it out for actual results with the new machines.

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post #648 of 1073 Old 09-29-2012, 11:13 AM
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We keep talking about the iris fully open. if you are running your system that way, then technically you do not have your system set up properly. In a correctly sized system, there should be extra lumens and the iris closed down to the point where we get the correct amount of foot lamberts off the screen. I would be willing to bet that the vast majority of JVC owners do not set up their system so that the iris is used in the fully open position. Of course at some point, they may get to that position when the lamp dims. With the newer lamps, if they live up to expectations (I personally think they will since JVC has increased the warranty) then people should be able to use their projectors with the iris closed down more and have to open the iris at a much slower rate. This also should help increase real world contrast. I am running short throw, due to room depth, but my iris is closed down 3/4's of the way. I am nearing 500 hours on my version 2 lamp.

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post #649 of 1073 Old 09-29-2012, 12:58 PM
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Quote:
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We keep talking about the iris fully open. if you are running your system that way, then technically you do not have your system set up properly. In a correctly sized system, there should be extra lumens and the iris closed down to the point where we get the correct amount of foot lamberts off the screen. I would be willing to bet that the vast majority of JVC owners do not set up their system so that the iris is used in the fully open position. Of course at some point, they may get to that position when the lamp dims. With the newer lamps, if they live up to expectations (I personally think they will since JVC has increased the warranty) then people should be able to use their projectors with the iris closed down more and have to open the iris at a much slower rate. This also should help increase real world contrast. I am running short throw, due to room depth, but my iris is closed down 3/4's of the way. I am nearing 500 hours on my version 2 lamp.

Good to know Mike! I use mine in a similar fashion to yours. Short throw, low light mode, aperture cranked all the way down to -15, 200 hours on the Rev.2 lamp. It's still nice and bright with no itch to crank the aperture open on a 120" screen.
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post #650 of 1073 Old 09-29-2012, 01:13 PM
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Both native on/off and brightness are equated by non-linear responses by the eye, and it is very response based.
So I don't think it's fully accurate in saying you need a doubling of native on/off to see a worthwhile improvement (possibly in some situations), but it depends on many factors like how bright the image is to how the response of your eye perceives the increase in contrast in the first place.

Take just brightness as an example, it's often said that we need to see a 15% to 25%+ decrease in brightness to notice by eye, that may be true in general normal viewing, but only if you start from a certain fL. When going from 18fL to 16fL to 14fL to 12fL to 10fL to 8fL in normal viewing, none of these transitions will be noticed to the same degree, it will actually generally be more suddenly noticed at some points than others (even if accounting for exact % difference rather than actual numerical difference).



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post #651 of 1073 Old 09-29-2012, 01:32 PM
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I wouldn't trust Native On/Off readings when they get this high, it's hard to measure it correctly. I base this on the fact that everyone ended up with different measurements for the JVC's. I'm not saying Cine4Home's measurements are wrong, but I'm just saying you can't know for sure.

You need a lightmeter with the right specs to do this, and you need to measure from the projector, not the screen. Cine4home measurements are completely in line with all the measurements I made using a Tecpel lightmeter on my rs20, rs50, rs45, and the rs55 I briefly had for evaluation. Many reviewers (I won't name them to spare them the embarrassment) and almost all users use colorimeters - or even worse, spectrometers - and/or measure from the screen, and there is no way you can accurately measure the black levels (therefore the contrast) of the JVCs doing this. The on/off you get using your calibration meters with calman or chromapure give a very vague indication, which might have a limited relative value, but is absolutely not a precise or trustworthy measurement of the performance of the projector.
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post #652 of 1073 Old 09-29-2012, 01:35 PM
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I am aware of needing a light meter (I have a couple). Didn't you measure the RS-50/55 at 79,000:1, not 50,000:1.
Cine4 measured < 50,000:1 with the IRIS closed. I looked at the measurements from reviewers that used light meters, and almost none are in agreement that I saw.



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post #653 of 1073 Old 09-29-2012, 02:16 PM
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When I said in line, I meant the variation between iris close/open between different models, you are right I should have been clearer.

I don't trust my measurements as absolute measurements as my Tecpel is not accurate enough for that. I had an opportunity to compare my Tecpel results with a friend having the same meter (in the same setup), and there was more than 10% difference.

But I trust it for relative measurements, to measure the differences in the same model depending on the settings, or to compare measurements between models I've owned or evaluate. I usually say that I don't trust my measurements if I post them, I hope I didn't forget that time....
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post #654 of 1073 Old 09-29-2012, 02:25 PM
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Your result is about a 60% increase compared to Cine4's, makes the comparison at least partially irrelevant.

The error margins are also non-linear on the different meters given bright to dark (we had long discussion about this in the lamp thread).
You can have + or - 5% at the top-end and -2% at the low-end on one meter, but have +1% at the top-end and + or -8% at the low end on another, yet if they both read at opposite spectrum of their error margins, then the margins are deviated by the potential range of two devices maximum margin on both lower and upper bounds. The angle and positioning of the meter might be another 5% to 15% between two disparate measurements. Combine both and we're looking at > 20% without accounting for other factors (but in the real world the numbers are often off by 25% to 50% or more depending on techniques).

I'm not arguing if one should buy one projector or another (I admit difference is not that big), but it's not really easily quantifiable looking at measurements (might be easier to quantify by eye), but I suppose trying doesn't hurt...



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post #655 of 1073 Old 09-29-2012, 02:34 PM
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Please read above, we are saying the same thing. These measurements are not very useful as absolute measurements unless you have a reference instrument. But the variations between settings measured by cine4home completely tally with the measurements I made, even if the absolute values are different.

In any case, we completely agree for the values iris open, it's only if you close down the iris and when dark levels become more difficult to measure that the errors creep in.

A very small change in the off value means a huge change in the on/off result. Most lightmeters are simply not accurate enough with the JVCs black levels to come up with the same results.

Also, as Geof said, a difference of 40000:1 makes a huge difference when going from 10000:1 to 50000:1. I don't believe it is nearly as significant when going from 50000:1 to 90000:1. After about 60000:1, I'd rather get an improvement in ANSI than further on/off (unless I can get both)..
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post #656 of 1073 Old 09-29-2012, 02:58 PM
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Cameras use a "stop" as an adjustment graduation, each "stop" is a doubling or halving of light and the adjustment steps are that large for a reason.

Those who have a projector with an adjustable iris can go from full open iris to full closed and get more variance in CR than they will get by going from a base model JVC to an RS56. When I do that test the main thing I notice is the change in brightness and black level, the change in CR is very difficult to perceive.
When I use a neutral density filter or lamp power to equalize the brightness and black level between iris open and iris closed I really dont think I could reliably pick the difference in CR even though it changes by about 50%.

As far as I am concerned all the JVC's have inadequate CR and far from perfect blacks, a complete change in technology is going to be required to really improve CR to the point where blacks actually look black. Until that happens we have to put up with various shades of grey.
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post #657 of 1073 Old 09-29-2012, 03:30 PM
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It is hard to notice, except for the bright corners issue on the RS-45 makes it easier to notice since it's reducing the contrast in the corner of the screen to probably sub 5000:1...
That said, my bright corners issue is no longer noticeable unless I'm really using specific content since I am not watching the PJ as bright as I was before.



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post #658 of 1073 Old 09-29-2012, 03:34 PM
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Quote:
Originally Posted by AV Science Sales 5 View Post

We keep talking about the iris fully open. if you are running your system that way, then technically you do not have your system set up properly. In a correctly sized system, there should be extra lumens and the iris closed down to the point where we get the correct amount of foot lamberts off the screen.
I hope I'm not implying that. In my particular setup my iris was at -12 initially and is now at -10 for the same ft-L.
Quote:
Originally Posted by Manni01 View Post

Also, as Geof said, a difference of 40000:1 makes a huge difference when going from 10000:1 to 50000:1. I don't believe it is nearly as significant when going from 50000:1 to 90000:1. After about 60000:1, I'd rather get an improvement in ANSI than further on/off (unless I can get both)..
Darinp said something very similar as well when the RS40/50/60's were introduced and he ended up getting the RS40. I have a near bat cave (fidelio velvet on walls and ceiling cover most of the room -- and all of the room in front of the seating) so yes, I'd like to get every bit of on/off but I'm confident I'll be happy with the RS4810 and $1500 in my bank account. To me the extra on/off is the only selling point of the RS56 (over the RS4810) as I consider all of the color modes and profiles and THX mode a complete waste. All I need is one colorspace that is over saturated with correct hues that is fully correctable with the 125pt calibration. The extra $1500 is basically buying just a tad more perceived on/off and if there is any room light it becomes moot.

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post #659 of 1073 Old 09-29-2012, 03:40 PM
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Unless there are other unknowns, like sharpness (streaky white text issue), bright corners, posterization differences post-cal (VP or not). The RS-45 had more of these issues than the RS-55, not saying the 4810 will.

I would also not base a buying decision on NATIVE On/Off alone, which is why I own the RS-45 and not the RS-55, to me the huge difference in price at the time was not worth the money, but to some it was (but personally I'd rather own JVC + DLP then an RS-55 alone, e-shift or not, but everyone is different).



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post #660 of 1073 Old 09-29-2012, 03:45 PM
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My RS55 has bright corners and I am of the belief that sharpness and uniformity and convergence, etc are luck of the draw. I don't see why the RS45 would have more posterization than an RS55 if they are calibrated properly. Tom Huffman told me his personal RS45 is damn near perfect with the Lumagen 125point cal and that is something neither he or I can achieve with my RS55......

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