KRAS Muzik ISF SP7210 review - AVS Forum
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post #1 of 50 Old 06-06-2005, 05:41 PM - Thread Starter
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Technically this is not an ISF review - rather a ColorFacts analysis. As you will see - I did not have to ISF the projector! Guess I will just have to go watch a DVD instead.

I got the luck of the draw with a very nice spectrally balanced lamp - not so much yellow-greens, and a bit of red push.

CIE1939

But lets look at it more subjectively with a more modern chart, which accounts for the eye seeing red/blue color difference more than green color difference.

CIE1976

Nothing really to complain about with colors!


Time for some brightness and contrast measures. First we perfectly align the sensor, and use a small image size for high black level accuracy.

1) 2' wide image verified with poster board at sensor - OK

2) Image center aligned exactly with sensor diffusor - OK

3) Sensor tilted back to return reflection dot back to projector lens - OK

MEASUREMENTS!

TEMP/LAMP/ND2? white_ftL/black_ftL = contrast ratio @ Lumens (to tens place)

6500K/LO 406.1/.234ftL =1730:1 @ 910 L
7500K/LO 535.9/.234ftL =2290:1 @ 1210 L
9300K/LO 396.1/.236ftL =1679:1 @ 890 L
7500k/HI 647.1/.283ftl =2285:1 @ 1460 L

OK I was a bit sloppy with those numbers - now that I am light adapted. I see the room is not pitch black - light sources are on - so let me fix that.

Cover rack with dark towel, close laptop, shut attic door, turn off microwave nightlite , mask projector LED. Security lights still on in yard leaks thru blinds/drapes - room is not pitch black - but at least I am 0.005ftL blacker.

6500K/LO 396.1/.229ftL =1746:1
7500K/LO 527.0/.229ftL =2303:1

ND2 increases contrast as it is slightly green of neutral

6500K/LO/ND2 210.5/.114ftL =1849:1
7500K/LO/ND2 278.6/.114ftL =2454:1

ANSI is 343:1 w.o ND2, 298:1 w/ ND2


ISF RESULTS

NONE!

This projector lamp was spectrally balanced out of the box - it achieved D65dE=3.4 without calibration (though ND2 degrades to D65dE=11) - thus there are no contrast losing RGB gain/offset adjustments. Gamma was perfectly tracked at 2.24. White peaking control is absent and good riddance - as indicated with perfect tracking gamma/greyscale results at full white.

So I got lucky on the demo stock - normally Infocus is significantly brighter than spec with a bit more yellow greens, and a redder greyscale out of the box to account for lamp burn-in. But the downside to only a bit brighter than spec - is some really nice contrast!. This is not unique to this box - as I have tracked all my SP4805 stock and observed similar brightness vs. contrast tradeoff and accuracy variations with lamps.

I will update this post in a few months after 10% lamp burn-in - which is when I recommend that ISF be done for that last 10% of hidden perfection!
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post #2 of 50 Old 06-06-2005, 07:35 PM - Thread Starter
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So how to use this info?

ftL = lumens * gain / square_feet

or if you have diag in inches

ftL = 337 * lumens * gain / (diag^2)

I like to target 24ftL to account for lamp dimming, use a ND2 filter initially you are at 12ftL movie brightness yet you can take it off when it gets too dim - its like getting a new lamp for free.

Or target 16ftL if you want an average 12ftL over lamp life with no filter used.

You will need 3x brighter if you want daytime TV rather than movie brightness - either do it with the screen gain or size, or get some help with high power lamp and 7500K for a 1.6x lumens boost.

I use the 880 lumens spec for low lamp 6500K - because you never know if you got the dim factory lamp - so consider actual brightness an extra!
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post #3 of 50 Old 06-06-2005, 08:14 PM
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Ok, I cut and pasted my little contribution from the other thread too...:D

Thanks, Kevin!!

Now let's see if I can interpret this information correctly...:cool:

6500K/LO 396.1/.229ftL =1746:1
6500K/LO/ND2 210.5/.114ftL =1849:1
ANSI is 343:1 w.o ND2, 298:1 w/ ND2

These are three most important sets of numbers, right, since people will generally be watching at 65k in low lamp mode with or without the ND2X filter?

So the contrast ratio of your 7210, with a 4 hour old lamp, is 1746:1 without the filter and 1849:1 with. Is this correct?

The ANSI contrast ratio is 343:1 without filter and 298:1 with filter. So the addition of the filter causes the ANSI contrast to lower while the on/off contrast increases? And the black level lowers with the filter as well from .229 down to .114)?

And the grey scale tracking is right on the money right out of the box?

And ANSI lumens at 6500k calibrated (since it didn't need calibration) is 910 in low lamp mode without filter?

How am I doing? Am I getting this right?
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post #4 of 50 Old 06-06-2005, 08:46 PM
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So plugging in my numbers, I come up with:

ftL = 880 (lumens) * 1.3 (Firehawk gain) / 38.9 sq. ft. (100" X 56" / 144")
ftL = 29.4 with no filter
ftL = 14.7 with ND2X filter

So I am slightly above 12 target footlamberts with the filter in place, and a bit below TV brightness with the filter removed....cool!

After viewing for extended periods of time with both the filter on and the filter off, I have to say that I now prefer the look of the brighter (filter off) picture, even in total darkness. My lamp has about 200 hours on it, so I assume that I have lost some of the initial brightness....Would a 10% reduction be likely? So without the filter I am around 26.46 ftL...a brightness level I like a LOT!

The other thing I notice is that even though on/off contrast is higher with the filter in place, what I call "real world contrast" appears greater, so what I am noticing is what I assume is properly called "ANSI contrast". Is this correct? Sure, the blacks look slightly blacker with the filter in place, but overall, I prefer the bright, punchy picture I get with the filter removed, despite the fact that I am seeing a higher black level. And the contrast appears to be greater, despite the fact that the on/off CR is lower.

Black isn't all that it is cracked up to be!! I have had a 9" CRT for some 4 years before switching to the 7210, and I am very glad to give up the very low black level and high on/off contrast of the CRT in exchange for the high apparent (ANSI?) contrast, the bright, punchy picture with rich and accurate colors, and the uniformly lit and sharp picture delivered by the 7210. For my personal tastes, high brightness means much more than CRT blacks. The blacks produced by the 7210 are more than good enough to keep me very very happy. Maybe I'll feel different after a year or two of this, but right now I am a very happy CRT convert!
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post #5 of 50 Old 06-06-2005, 08:50 PM
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Kras,

Maybe I missed it, but what mode where you in for the lumens test? Was it film mode? Do you have any idea how projectorcentral.com could have come up with just 400 lumens? They say that had it in "(lamp standard, gamma set to "film", white peaking off, with the color temperature set to 6500K)." I know we could chalk it up to incompetence, but I'm wondering if there is something else we can deduce here.

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post #6 of 50 Old 06-06-2005, 08:59 PM - Thread Starter
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darinp2,

I think incompetence is the proper conclusion - PJC thought the SP7200 and BenQ8700 where the same brightness too. I honestly wonder if they actually measure projectors or go - "Hey another 1100 lumen projector to review - Joe you did the last 1100 lumen projector why don't you give me some numbers for my review....they are all the same marketing lies anyways" As many presentation and HT projectors that they review - how could they possibly keep up? I know how long it would take me to fully characterize & calibrate all inputs and all modes on a projector - I have done it. Not worth doing for free - that is for sure!

HT Mag vs. WSR reviews I think we can chalk up to lamp variances (assume +/-20% with Infocus spec being low bell curve), and certainly off-screen measures have variant losses depending on the screen - which PJC's own screen reviews suggest as well.

This is the reason I measure a 2' image without a screen - I want people to have projector numbers that they can use to pick a screen. My sensor can handle the high ftL - and I stay away from inaccurate low ftL.

The modes are just gamma curves - I prefer film for 2.2 gamma, CRT is 2.5 gamma. I will take note to plot the other curves. They do not affect other calibration measures (except PC gamma which screws up greyscale)
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post #7 of 50 Old 06-06-2005, 09:17 PM - Thread Starter
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Bob Sorel,

You are just seeing your eye bias from your IRIS stopping down. If you have any light in your room at all - this is a better way to go - it does seem to make black "blacker" even though physically they are not.

I once surveyed a customers room for light control - he was concerned about the window blinds to the parking lot (townhome). One window lite was hitting the screen - so I said drape that. The others though did not hit the screen - they hit my eye! As I was looking for light leaks on the screen his wife said something in the kitchen. She had a black pantsuit on and I could not see her for the life of me - my eyes had been biased by the window! I said - no drapes on these windows!

I am sure darinp2 disagrees with this approach since he uses contrast performers on a high gain screen to get 12ftL in a black velvet room - do you want real blacks - or do you want apparent blacks? For me - I am debating the $300 variable NDx filter so I can have a perfect 12ftL -always!

I like SciFi channel on Fri night and want decent blacks - but this living room plasmer simulator gets used as a day TV too.

The eye is an amazing thing - I was amazed how low the contrast actually was in darinp2 and I independent ambient room measures! The interesting thing is the ambient light destroyed color and greyscale - yet I could swear I could tell you if it was set for 6500K vs. 7500K!
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post #8 of 50 Old 06-06-2005, 09:34 PM
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Quote:
I am debating the $300 variable NDx filter so I can have a perfect 12ftL -always!
Whoa! That sounds really interesting, and certainly affordable! Though I might opt for a little higher than 12 ftL, having a continuously variable ND filter would be a great addition to maintaining uniform ftLs for the life span of the lamp. Who makes this filter and where can I get it (or at least learn more about it)?

Even though I prefer the higher brightness without the filter, I have to admit that in total darkness I find it a bit too bright. The problem is that I only have one filter, so I either have full brightness or half brightness. Like Darin has stated, the ideal solution would be a variable iris, but since that is not an option, a variable ND filter sounds like the nest best choice.
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post #9 of 50 Old 06-06-2005, 09:49 PM - Thread Starter
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Bob

Problem it is from a ND3 to ND10 not like the ND0-ND3 you probably want. Perfect for my plasmer vs. movie needs to save my marriage though! It is perpetually not in stock at B&H Photo - if it ever comes in stock I might buy it on impulse - forget the brand but search their ND filter list. Personally I think they are waiting for a sucker to place a will wait order before they stock it.

I tried a variable circular polarizer which worked when I held it up to the sun - then somebody told me I was an idiot since DLP light is not polarized - so it works as a ND3 just not variable!
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post #10 of 50 Old 06-06-2005, 10:21 PM
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Quote:
Originally Posted by krasmuzik
I tried a variable circular polarizer which worked when I held it up to the sun - then somebody told me I was an idiot since DLP light is not polarized - so it works as a ND3 just not variable!
I'm not sure how much loss you would get at open, but you basically need two polarizers and then just turn them to either be in phase or not. This won't work with anything except single chip DLP that I know of since the 3 chip/panel digitals tend to have green polarized different than red and green. I think you can do this for way less than $300 with two of these. I may have a couple sitting around I could try, but I'm not sure where they are.
Quote:
Originally Posted by krasmuzik
I am sure darinp2 disagrees with this approach since he uses contrast performers on a high gain screen to get 12ftL in a black velvet room
Actually, I aim for closer to 6-7 ft-lamberts for 100 IRE (brighter than 2 CRTs I have measured). And with the high CR most people are pretty impressed with how this ends up looking.
Quote:
Originally Posted by krasmuzik
- do you want real blacks - or do you want apparent blacks?
All I care about is apparent. "Real" means nothing to me for video other than something looking like it is real (whether it is or not). What you are talking about is basically bias lighting. I have no problem with that, but haven't personally found any situation where I preferred it other than a plasma with horrible CR.

Your point about not seeing her outfit is one of the problems I have with bias lighting. I don't just want black blacks, I want shadow detail. And biasing to the point of killing shadow detail so that people look like heads on black holes is not something I prefer. It could be that I could find a good compromise that I would prefer with some kind of bias lighting, but I didn't find one in the small amount of testing I did.

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post #11 of 50 Old 06-06-2005, 10:37 PM - Thread Starter
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Good point about shadow detail - I think that is why I prefer 12ftL. It is not so much that I see rainbows or get headaches - it just seems I am missing out on something! Like my eyes are seeing stuff but my brain says you are being fooled!

12ftL is more filmlike. Also it only works in a dark room - yet a dark room is part of the magic of HT - if I can see the room I am not being transported into the movie! For me drawing the curtains and dimming the lights is part of the experience. Maybe it is because I did plays in highschool - it comes from that. But even the local multiplex do not draw the curtains anymore - and they leave "safety" lights on - I hate that!

I assure you the circular polarizer does not work as variable - I rotated it till I was blue in the face. It does work against the sun - which is why I bought it. One of the gals (yes we have one of those!) at my meets is an optics engineer for the scanners at HP - and she was laughing her head off. So I gave up on my variable filter search - since the only I have found is never in stock - and will only work on my plasmer simulator anyways!
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post #12 of 50 Old 06-07-2005, 12:25 PM
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Quote:
Originally Posted by krasmuzik
Good point about shadow detail - I think that is why I prefer 12ftL. It is not so much that I see rainbows or get headaches - it just seems I am missing out on something! Like my eyes are seeing stuff but my brain says you are being fooled!
I think higher ftL do help to see things, but so does getting higher CR off the screen. In other words, more separation between the darkest and brightest objects can help make detail more visible. In the past I have thought that I wanted more lumens, when what I really wanted was more separation between objects so that I could make them out easier.

Quote:
Originally Posted by krasmuzik
12ftL is more filmlike.
Do you mean more filmlike than 36 or more filmlike than 6-7? As I've mentioned before, I would be pretty surprised if that average commercial cinema on any day was even 10 ftL. Screening rooms are probably different, but my eyes tell me that the commercial presentations I go to are not generally 12 ftL, but quite a bit lower. I believe that 6-7 even looks in the range I am used to at commercial cinemas and with the higher CRs can actually look punchier to me.

Quote:
Originally Posted by krasmuzik
Also it only works in a dark room - yet a dark room is part of the magic of HT - if I can see the room I am not being transported into the movie! For me drawing the curtains and dimming the lights is part of the experience. Maybe it is because I did plays in highschool - it comes from that. But even the local multiplex do not draw the curtains anymore - and they leave "safety" lights on - I hate that!
If you are ever up near Seattle and want to see what 6-7 ftL looks like in a mostly black velvet room with pretty high on/off CR (we're not talking 2k:1 here :)) and high ANSI CR, just let me know.

Quote:
Originally Posted by krasmuzik
I assure you the circular polarizer does not work as variable - I rotated it till I was blue in the face. It does work against the sun - which is why I bought it. One of the gals (yes we have one of those!) at my meets is an optics engineer for the scanners at HP - and she was laughing her head off. So I gave up on my variable filter search - since the only I have found is never in stock - and will only work on my plasmer simulator anyways!
I was talking about using 2 filters. You rotate them against each other. I'm not exactly sure which kind you need, but I think you might need linears. I grabbed two polarizers I have that say "SR Polarizer" on them and tried them with the 11k last night. I think one filter was the $12.95 linear polarizer here and the other was one size up. I held a lightmeter out and with them turned so that the max light went through it was blocking about 75%. Turning one to go the darkest blocked about 95%. However, the darkest was very cyan and I'm not sure why.

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post #13 of 50 Old 06-07-2005, 12:57 PM - Thread Starter
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Yes I do think contrast ratio makes things look brighter - I think this is why people thought the SP7210 was brighter (aside from new lamp variations). Does DC3 really have benefit to brightness - as everything else in the box is identical! I suspect Infocus raised the lumen spec because TI told them this - then once they got final production - they were not really seeing it and in all honesty backed of the brighter spec.

With high ftL you see more than you are intended in the shadow detail - greater distance between black levels. Plus white levels - just like a bright TV in a dark room gives me headaches. For an ambient room - we have proven you need brightness to get any contrast at all (gain/lumens)

I have had the dim ftL with the Runco running a 8'x6' screen - but maybe you are right - it was low contrast so I have to see dim ftL with high contrast yet. I prefer to design to screening room standards though - which is a very tight 16ftL tolerance (derated to 12ftL for digital cinema - I think hot whites they allow 14ftL)

I highly doubt the theater clerks know how to change the butter dispenser - forget about the lamp! So I don't disagree with you there. Until we get HDVD and theater releases same day - and I get a CinemaScope room built in the basement - then I try not to miss the blockbusters before the prints go bad. Sometimes I think I go just for the popcorn/nachos/soda - at least the local second run still does the drape thing!

Anytime I go up to Seattle - it is a full day job. Three hours up, three hours calibrating, three hours back - I just did it last weekend (for free thanks to Infocus and their screwed up firmware). I would not mind going up for a local AVS meet though! We are having one soon with a 480P DC2 shootout.
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post #14 of 50 Old 06-07-2005, 01:03 PM
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So where is the review?? All we have here are contrast and brightness measurements. Did it make your porn collection better??? :p
Inquiring minds want to know!!
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post #15 of 50 Old 06-07-2005, 01:04 PM
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Quote:
Originally Posted by krasmuzik
Anytime I go up to Seattle - it is a full day job. Three hours up, three hours calibrating, three hours back - I just did it last weekend (for free thanks to Infocus and their screwed up firmware). I would not mind going up for a local AVS meet though!
How about Olympia? It is someone else's house and not really an AVS meet (just 3 of us looking at a CRT and a digital), so I would have to check with them first.

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post #16 of 50 Old 06-07-2005, 01:09 PM - Thread Starter
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How much farther is Olympia (yes I have not been their!) - feel free to drop buy our local AVS meets thread. I am sure we don't mind some cross pollination trips! Really that is what our meets turn out to be - us long time members getting together - with the occasional newb that needs coddled. Other guys go to the bar for a beer and watch the game - we get together to look at projectors - what a bunch of geeks!
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post #17 of 50 Old 06-07-2005, 01:13 PM
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Quote:
Originally Posted by krasmuzik
How much farther is Olympia (yes I have not been their!)
I'll send you a PM. It is maybe 90 miles south of me and 105 miles north of you up I-5. I don't think I can invite a whole group since it isn't my place though.

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post #18 of 50 Old 06-07-2005, 01:20 PM - Thread Starter
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Tyro

That is why it is an ISF review! You get what I would give you for ISF - just on a fancier report. I can put the display analysis report up on my site if you want to see the graphs.

Read the other sites for stuff like what is on the menus and what ports it has.

If it makes you feel better - I will do my best at a guitarman style review.

"

The yellows were so lemony the juices were running down the screen. The blacks were infinite like a black hole, and the whites were like the vision of the Pope! Once I saw the blues I felt the need to start pecking out a tune on the geetar and blow my harmonica! This projector will blow out darinp2 blackvelvet room with blacks darker than the walls of the deepest dungeon - yet at the same time you could use it as the half time screen at SuperBowl stadium. This is currently the best projector on the planet - at least until I take screenshots of the next one. In the meantime I am going to have a CEEGAR that I just had imported from my buddy in an unmentionable country - and sip a fine brandy. I figure once I fry my brain with these vices - the picture will look even better. Sorry I cannot take a screenshot of my brain so you can see what I see!


http://krasmuzik.home.comcast.net/VSSFRIENDS.JPG

I think I have topped myself with this screenshot - the rest of you give it up to the master!

Oh and before I forget - I have to mention the deinterlacer/scaler. This thing is crispier than the toast I burnt last nite - yet I don't know how the engineers did it - it was still smoother than the melted butter I put on it!

"

Or something like that.....Sorry Tom - I could not resist!
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post #20 of 50 Old 06-07-2005, 02:00 PM
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HA HA!!*
















* you didn't mention it being quiet as a church mouse ( which if it is the H79, it is ! )!!

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post #21 of 50 Old 06-07-2005, 02:03 PM - Thread Starter
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What?! I Can"t Hear You The Projector Is On _ The Space Station Got Of Track And They Asked Me Send Up A Beam _ Like In That Apollo 13 Movie So They Could Find Earth Again :d :d

(DAMN THE NEW FORUM HAS AN ALL CAPS FILTER - IT IS FUNNIER IF YOU CAP IT)

NOW WHY DID THAT EDIT WORK?
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post #22 of 50 Old 06-07-2005, 06:14 PM
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After reading yet another review of the 7210 in the latest Home Theater magazine, I have come to the conclusion that NO ONE ON THE FACE OF THE EARTH KNOWS HOW TO MEASURE LUMEN OUTPUT!!

Home Theater called the 7210 "The brightest projector ever...again" and "Can be used as a signal flare" and "Crazy bright (of course)", yet they claimed 25.62 ftL on their 87" wide, 1.0 gain Da-Lite Da-Mat screen, using a full field 100 IRE white test pattern in low mode. If I am correct, this translates to 758 lumens, which seems pretty low to me, and certainly lower than Kevin's measurements, and again different from any other magazine reviews.

Here are some of the other specs from the article:

ftL in low power mode - 25.62
ftL in high power mode - 28.91
on/off CR in low mode - 1423:1
0n/off CR in high mode - 1378:1
ANSI CR in low mode - 419:1 (using 16 box checkerboard pattern)
black level (0 IRE) in ftL in low mode - 0.018

The biggest fault that HT found was in the color decoder. They posted measured color points:

Red: x=0.655,y=0.328
Green: x=0.335, y=0.572
Blue: x=0.149, y=0.072

Quote:
The gray scale as set by the factory, in the 6500 color-temperature mode, measures slightly warm across the gray-scale range. After making adjustments using the Photo Research PR-650, the gray scale measures within 99 Kelvin of D6500, the accurate color temperature, across the entire range, though the darkest images are slightly warmer.
And later, in the text:

Quote:
On the other hand, color isn't this projector's strong suit. It's not bad, but it is not nearly as accurate or as vibrant as several other projectors we've had in recently. When you look at them on their own, the colors don't appear off, but they don't llok exactly right, either.. Scenes like capter 5 of The Fifth Element, where there are many differently colored objects (like the hallways, the fish, and so on), just don't grab you like they do throughsome other projectors.
They are not looking at the same projector that I am watching. The bright, accurate, punchy, well saturated colors are one of things that drew me to this projector in the first place. Once again, I have to wonder if they bothered to set up the projector properly, reducing the ftL down to ~12, or if they just made their observations at the full 25.62 ftL that they measured earlier.
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post #23 of 50 Old 06-07-2005, 07:25 PM - Thread Starter
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It tracks what they measured on the SP7205.....so they are internally consistent. In the other thread I compared their Marantz review to WSR - which was the only one I could find for identical mode settings - and WSR was 1.5x higher.

I think the difference is WSR measures off a Stewart ST130, while HTmag measures off a DaLite DaMat. Now darinp2 thinks PJC was accurate in their screen reviews - ST130 meeting spec while it had Dalite CInemaVision at 15-20% less than spec - now realize that that is a coated screen which should reflect better than a pure vinyl screen - I would expect DaMat to show even a greater loss (the sample I have seems thin & translucent even) Combine that with a +/-20% bell curve for lamps.

You want a good laugh - compare PJC H79 lumens of 450 vs. their SP7210 lumens of 400. Would you agree with that considering you saw the ND2 filtered SP7210 as the H79 brightness equal in direct comparison - cause according to PJC you should have seen the ND2 filtered SP7210 as less than half as brite! I don't think you can attribute PJC measure differences to lamps or screen differences!

I eliminate the screen as a variable in my measure - if your screen has loss below it's rated gain - then that needs to be accounted for in your ftL calculations. I saw a similar drop with an Eye-One off BlackOut cloth vs. my direct method (at first I accused the Eye-One - but darinp2 said he compared it to his work instruments OK)

Have a look at htprojectors.com review of SP7205. You can see our CIE charts are all similar (though Andreas did a later CIE where their sensor failed to read saturated blue - the Eye One can do this if you fail to keep up dark readings). Their contrast is similar to what I measured for SP7205 - though their ftL does not track in calibrated mode either (again screen measures).

Now figure I got a dimmer but higher contrast lamp for SP7210 - and I think things track.

Here is what htprojectors.com said about SP7205 color (color is identical on SP7210 - only DC3 changed)

"From these charts I think we have a straight explanation why InFocus’s machines are so widely popular and sold: please take a look at the close resemblance we have between this curve and the “ideal†one we should expect from human eye. Colors are wide and deep, at any IRE level, even without the help of a Xenon lamp. This gives us a good idea of the great results these units have from sales: if you watch at something that is natural, you can’t be but satisfied. Please not the slight shift in green position, that is not centered on the “pure greenâ€, that is the same we noticed within the CIE chart"

Note the use the 1939 chart - can you see the difference with my 1976 chart? Why is it our 1939 charts are all similar - yet htprojectors.com liked the color? Do you think it is possible some reviewers think vivid color is natural and accurate - then when exposed to natural accurate color - don't like it? Also ftL does impact color perception - I saw this in my H30 vs, SP4805 shootout - which I did with same size screen (and thus dimmer H30) and then with same ftL - guess what color perception differences were less obvious (aside from the cleary oversaturated H30 green)

Now Andreas in his htprojectors.com review did bitch that the gamma was 2.5 rather than 2.2 - I found it strange that they measured no change when they switched from 'CRT' to 'film' as I always do measure and see change. This control clearly works for me - you want psychovisual contrast use CRT - you want black detail use film. And of course they still think it is too bright - but then they love to watch the dim SIM2's so whaddya expect!
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post #24 of 50 Old 06-07-2005, 07:39 PM - Thread Starter
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PJC said your firehawk was really only 1.15gain rather than 1.3gain - which I think I would agree with. I would not adjust your ftL since it is likely that your projector is brighter and compensating for the 12% drop in spec. I only got 5% over - but that is low - since my SP4805 stock shows Infocus lamps are likely higher on average.
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post #25 of 50 Old 06-07-2005, 08:21 PM
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Hehe, Kevin....I just find it odd how much the lumens output spec varies from one reviewer to the next. Come to think of it, there are a lot of specs that vary wildly from one review to the next, from one manufacturer to the next, etc. What we really need is for someone to step up to the plate and establish a standard set of measurements and techniques so that consumers can accurately compare specs from one piece of gear to the next. As things stand now, with all of the "fudging" of the numbers being done by manufacturers, as well as inconsistencies in measurement techniques from people who are actually trying to give meaningful data, consumers are being left totally in the dark when [i]attempting[i/] to compare projector numbers. I trust my eyes a lot more than I trust any numbers, and I thank God for people like you who explain what is going on so that we can get the most out of whatever we have, as well as understand the huge variations in reported numbers. If all I did was to compare specs, I would be so totally confused that I might just give up and take up knitting instead...:)

Thanks once again, Kevin!
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post #26 of 50 Old 06-07-2005, 08:41 PM - Thread Starter
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Actually Runco tried to do that very thing.....

http://www.runco.com/Widescreen%20Re...MS%20story.pdf

They even said let's use ftL so we can still publish our high ANSI lumens (which is what PJC type search engines use) - and ftL allows one to compare to theaters without math (of course you have to scale their ftL to your screen area & gain difference). And they also use the ST130 - but on a 6' wide. They also compare to a standard 1.0 gain surface - and indeed find that the screen sometimes is not 1.3!

At least magazines tried to follow this ftL standard in their review - but then they all picked different screens - so reviews are no longer comparable unless you do the math - but catch22 you must know what screen gain REALLY is.

I have had two projectors on the stock bench at the same time - and told my good customers they can have their pick - do you want brighter or blacker! See I do the identical Colorfacts analysis everytime so they get their report with the projector - they know what they got! Even if they picked brighter I caution them to design their screen setup using spec not measure - who knows what their next lamp will measure!
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post #27 of 50 Old 06-08-2005, 11:41 AM
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Quote:
Originally Posted by krasmuzik
PJC said your firehawk was really only 1.15gain rather than 1.3gain - which I think I would agree with.
And people should keep in mind that this is only for the hottest spot. With the Firehawk it can drop off fast. 12 ftL at the center and 6 ftL at the edges is more than 6 at both (which is basically the range I shoot for with the High Power in my dark room), but it is still less than 12 at both or even the approximately 12 and 9 that I would guess for a StudioTek 130 with the same ftL in the center.

Quote:
Originally Posted by Bob Sorel
Hehe, Kevin....I just find it odd how much the lumens output spec varies from one reviewer to the next.
Here is my guesses for a couple of reasons. Many of our colorometers aren't as accurate as we think and there is a big variation between what people will read for the same setup. So, some are adjusting the colors and getting different ftL. Then some are probably leaving some room for above reference whites (video 235) and some are not.

--Darin

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post #28 of 50 Old 06-08-2005, 11:57 AM
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I would trust Geoff at HT-Mag. He's using a Minolta LS100 which should be very accurate. Someone fill me in on what Greg at WSR is using, (accupel signal generator) how would this device work and how accurate?

Tom/guitarman
VideoDementia

Are you twisted also?
http://www.videodementia.com/sales/TomWithWires.jpg
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post #29 of 50 Old 06-08-2005, 12:28 PM
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Quote:
Originally Posted by guitarman
I would trust Geoff at HT-Mag. He's using a Minolta LS100 which should be very accurate.
Even if the LS100 is totally accurate, if he has rebalanced the colors because his meter for that isn't accurate, then his numbers would change. I would put my most stock in the WSR guys. I know one of them uses a known D65 light source for making sure his colorometer is accurate.

BTW: Is Geoff one of these guys who measures black level off a full sized screen with an LS100, gets one or two digits, and then reports on/off CR with more digits of accuracy. If so, I would put very little trust in his CR numbers with high on/off CR projectors or his understanding of accuracy.

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post #30 of 50 Old 06-08-2005, 01:30 PM - Thread Starter
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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.

Yes indeed if someone is reporting ANSI lumens - then the 9pt will lower the number - and significantly on a high gain screen. Was not aware if anyone doing that. I prefer a center measure - then a uniformity measure - this carries more information.
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