KRAS Muzik ISF SP7210 review - Page 2 - AVS Forum
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post #31 of 50 Old 06-08-2005, 03:33 PM
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Quote:
Originally Posted by krasmuzik
Good point about the hot white adjustments - I have not done it because visually it is a major contrast loss (I will leave a preset for it on request). I have never thought to measure it for loss - though I suppose it can be figured if you know the gamma. What is the 2.2. gamma math for that.
We might be talking about different things. I was just talking about the fact that the Firehawk gain drops off pretty fast toward the edges in most setups because it has that high gain angular reflective layer. At about 2.0x for the throw and sitting at about 1.6x I think the dropoff was close to 50%, but it might have been more at the very edges.

Quote:
Originally Posted by krasmuzik
Yes indeed if someone is reporting ANSI lumens - then the 9pt will lower the number - and significantly on a high gain screen.
Except for the High Power (and probably Torus screens). The High Power tends to have good uniformity because of the retro-reflective nature. But if people are reporting ANSI lumens for a projector and the screen is throwing them off, then they are doing it wrong. The ANSI lumens should be independent of the screen.

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post #32 of 50 Old 06-08-2005, 03:36 PM - Thread Starter
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darinp2

I saw one site do that very thing! Reported screen measurements figuring the 9pt method as a projector review!

Was your FireHawk test ceiling mount? I think my FireHawk setup was more like 2.5x throw and ceiling mount - I would be surprised at 50% dropoff - but I only ever measured viewing angles not uniformity.

ANSI method is very difficult to control using a projection image not a screen so I can see why people do it on screen. But how do you control it so the sensor angle is same - do you point back at the lens or do you keep sensor parallel each measure (and how do you ensure that?)

Anyways Infocus has said their spec is a 9pt measure - just not sure how they do it (I assume ANSI method gives requirements) - but that would account for why I have always measured higher than spec in the center - as well as the bell curve.
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post #33 of 50 Old 06-09-2005, 09:05 AM
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This is a silly question, that can only be answered by wild guestimation, but I'll ask anyway.

If I were looking out the window of my house on a clear bright day, roughly what would the ftl be? I am assuming it would look more like a TV brightness than movie theater brightness, no? Is there something to be said for having the brightness on the screen appearing like the brightness out my window on a clear bright day?
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post #34 of 50 Old 06-09-2005, 11:59 AM - Thread Starter
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Impossible to achieve light of reality - and your eye can still tell the difference between reality and digital anyways. But if you know of something as bright as the sun that I can use in the living room - let me know!

So instead we use standards developed by SMPTE. Maybe someday they will have standards for the holodeck that can achieve reality. Your goal is not to match reality outside - but to match the reality the director saw in their screening and mastering rooms. And that you can do!

Read darinp2 and my thread on ambient lite measurements. I easily measured 24ftL in my living room on a grey rainy northwest day. Says something about black levels when that is twice the white levels of the local theater - yet people strive to fool themselves into thinking that is "black"
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post #35 of 50 Old 06-09-2005, 01:00 PM
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Quote:
Originally Posted by skogan
This is a silly question, that can only be answered by wild guestimation, but I'll ask anyway.

If I were looking out the window of my house on a clear bright day, roughly what would the ftl be? I am assuming it would look more like a TV brightness than movie theater brightness, no? Is there something to be said for having the brightness on the screen appearing like the brightness out my window on a clear bright day?
I don't think it is a silly question.

White paper in sunlight is about 10k cd/m2. TV levels are about 1/100th of that or 100 cd/m2 with film levels around 40 cd/m2. That puts TV levels at what they call "comfortable reading". If you wanted real sunny day levels then the artifact visibilty would probably be pretty high as krasmuzik pretty much aludded to, since it wouldn't look like real life. The transitions in some films would be like going from a sunny beach to a dark cave and back, also. And at current on/off CRs the "black" scenes would be at pretty bright levels themselves with 10k cd/m2 for 100 IRE.

Here is a table (sorry that the formatting isn't right).

Code:
Light Levels for Visual Perception 
----------------------- Luminance (candelas per square meter) --- Adaptation 
Sun at noon --------------------------- 10,000,000,000 ----------Damaging 
Brightest light in which we can see -- 10,000,000  
Filament of a 100W Bulb -------------- 1,000,000 --------Photopic 
White paper in sunlight --------------- 10,000  
Comfortable reading ------------------- 100  
----------------------------------------- 1 ----------- Mesopic 
White paper in moonlight --------------- 0.01  
White paper in starlight --------------- 0.0001 ---------- Scotopic 
Weakest visible light ------------------ 0.000001
BTW: If you look you can see that if you want 100 IRE to be at "Comfortable reading" and video black to be at "White paper in starlight", then it takes 1 million:1 on/off CR. For video black to be "White paper in moonlight" with those TV white levels it takes 10k:1 on/off CR.

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post #36 of 50 Old 06-09-2005, 06:42 PM
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Interesting, thanks.

Edit:

- wow, there is a lot more fooling of the eye going on than I had assumed.
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post #37 of 50 Old 06-10-2005, 11:25 AM
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Kevin.................

How would your 7210 numbers compare to a 7205?

x% brighter??

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post #38 of 50 Old 06-10-2005, 11:35 AM - Thread Starter
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Hard to say - my previous review was with the older sensor that had drifted and thus read a lighter green (we are only talking 10% diff). So instead of 1100 Lumens, maybe I got 1000 Lumens.

I am not convinced that DC3 makes things brighter - what I do know is that increased contrast makes things appear brighter. This is because we define white in our brains based on what black is.

And I know for sure someone comparing old SP7205 to new SP7210 is going to think it is brighter - old vs. new lamp! That was my first impression - but I had 1000 hours old lamp!

Someone had posted a TI doc with DMD numbers and I am afraid it got pulled - I cannot find it in my files. Maybe they shined up the mirrors for brighter - I dunno?!

Combine that with lamp variations - I am not convinced that on average it is any brighter. And neither was Infocus - since their initial 1400 lumens marketed spec fell back to 1100 lumens.

On my SP4805 stock I measured 600-800 lumens (spec was 600) across all the lamps. That would be consistent with a 700 Lumens +/-15% bell curve spec.
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post #39 of 50 Old 06-10-2005, 04:18 PM
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Kevin,

My H78 was achieveing approximately 425 and 550 lumens on a 160 hour lamp (lo and hi modes), whereas the H79 is achiveing 575 and 700+ IIRC (Widescreen Review, less than 100hours I believe). I was only getting 398 and 500ish when new on the H77.

Other than the DC3 chip, I don't think there's a great deal of difference between the two machines, so on the face of it, there does seem to be more brightness (and more CR too).

Other than the DC3 chip, how else do you think they may have achieved that much more brightness? WOuld you attribute those gains to the chip or other means?

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post #40 of 50 Old 06-10-2005, 04:57 PM - Thread Starter
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If anyone can find that TI DarkChip doc it was on here a few months ago.....
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post #41 of 50 Old 06-11-2005, 08:19 AM
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I think you talk about the DC3-communication from TI. You have a new email with the attached *.pdf file Kras.

--Peter
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post #42 of 50 Old 06-11-2005, 11:53 AM - Thread Starter
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Thanks Peter!

I see nothing in there that implies brighter - just blacker!
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post #43 of 50 Old 07-25-2005, 03:03 PM
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Home Theater Magazine just did a review of the 7210. Verdict: Great blacks and brightness, but "color isn't this projector's strong suit". :eek:
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post #44 of 50 Old 07-25-2005, 04:10 PM - Thread Starter
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Which is a comment I do not understand - perfect blues, deep reds- with a lighter green for more light output - and of course perfect D65 greyscale/gamma and secondary colors. Look at the CIELUV I posted - which is actually how we perceive less green and more blues/reds. Compare that to other projectors......

What it does not have is unnatural 'vivid' oversaturated colors or pushed greyscale (The reds tone down after lamp burn-in). As natural as video can be - what you see is what the video engineer saw more or less!

They were less than enthused about the Samsung optimized by JKP for video engineering perfection as well.....
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post #45 of 50 Old 07-26-2005, 03:39 PM
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Quote:
Originally Posted by acksnay
Home Theater Magazine just did a review of the 7210. Verdict: Great blacks and brightness, but "color isn't this projector's strong suit". :eek:

Home Theater Magazine is not a very good source of information. Especially when it comes to HT equipment not sold at your local Circuit City or Best Buy.

In the article he didn't even back up any of his color complaints with any numbers. Just saying useless subjective comments. Maybe if the review came from Widescreen Review or something on that level I would take it more seriously.

Joel

Proud 7205 owner. :)
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post #46 of 50 Old 08-15-2005, 12:47 AM - Thread Starter
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Just thought I would update after 200hrs

TEMP/LAMP/WP white_ftL/black_ftL = contrast ratio @ Lumens

6500K/LO/0 361.1/.204ftL =1773:1 @ 813 L
6500K/HI/0 442.7/.251ftL =1764:1 @ 996 L

7500K/LO/0 476.8/.203ftL =2354:1 @ 1072 L
7500K/LO/100 575.5//.202ftL = 2848:1 @1296 L
7500K/HI/100 707.8//.25ftL = 2830:1 @1592 L

D65 at100IRE measured CCT6673 for dE3 at brightness spec
D65at 100IRE measured CCT7261 for dE21 at contrast spec

The CIE chart red is a little bit deeper, greyscale is still barely Cyan. Not that much different than before aside from 10% brightness loss after 10% lamp burn-in

Interesting - with the Accupel 720 PCDVI - the white peaking is there - missed that before! It meets contrast spec with WP=100 and 7500K while it meets brightness spec with WP=0 and 6500K. High lamp uncalibrated it is twice as bright as the calibrated low lamp mode.

Wonder what this Quantary FL-D filter will do.....

7500K/HI/100/FLD 338.6/.108ftL = 3144:1 @761L

6101 CCT for dE11 - moved it from Cyan to Green-Yellow greyscale.


Couple clicks down on red/green....

7500K/HI/100/FLD/ISF 289.1/.105ftL = 2759:1 @650L



D65 is now 6545K CCT dE1! The white peaking is very slight - changes it from a 2.21 to 2.5 gamma with a bit of mistracking at 80IRE.

So a 20% brightness loss, 33% lamp life loss for a 56% contrast improvement....and that is not even a good Hoya FL-D filter......
This tweak does cost color accuracy though - Yellow/Magenta are pushed more towards the even more intense Red now.
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post #47 of 50 Old 08-15-2005, 04:16 PM
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Thanks for the update news Kevin, and for taking the time. :)

Gary.

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post #48 of 50 Old 08-15-2005, 05:30 PM
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Thanks for the update, Kev! Can you post the charts somewhere so I can get some experience reading them? :) Which CIE chart(s) did you use?

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post #49 of 50 Old 08-15-2005, 05:33 PM - Thread Starter
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I did not save the CIE charts - as they were essentially that of the first post CIE (except of course with the FL-D things changed).

I have been using my own color error charts lately - they are not ready for publishing yet....
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post #50 of 50 Old 09-30-2005, 01:25 PM - Thread Starter
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move to calibration forum!
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