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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sat Jun 22, 2013 3:46 pm Post subject: |
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Comparing ANSI measurements are worthless unless you are comparing in the same room.
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stridsvognen
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| Posted: Sat Jun 22, 2013 3:59 pm Post subject: |
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| Spanky Ham wrote: | | Comparing ANSI measurements are worthless unless you are comparing in the same room. |
Sure, but if there is enough feedback, you get a impression of whats normal, and maybe whats possible.
I posted a pic and described my room, to document that it should be possible to do better, but i guess im the only one using time to compare this stuff and try to improve it on different type of ptojectors.
I feel there is a bit of resistance to measure, and share calibration data in here, so ill try to control my curiosity.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sat Jun 22, 2013 11:07 pm Post subject: |
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| Spanky Ham wrote: | | Comparing ANSI measurements are worthless unless you are comparing in the same room. |
This was my theory on it too.
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SisterOfMercy
Joined: 31 Oct 2007
Posts: 155
Location: Zwart Nazareth, The Netherlands
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| Posted: Sun Jun 23, 2013 12:01 am Post subject: |
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| Spanky Ham wrote: | | Comparing ANSI measurements are worthless unless you are comparing in the same room. |
My room is the reference.
You are not allowed to take your PJ back with you, we will send it to you. Really, we will! 
_________________
The kissing and the colour come crashing down
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sun Jun 23, 2013 2:59 am Post subject: |
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| CasetheCorvetteman wrote: | | Spanky Ham wrote: | | Comparing ANSI measurements are worthless unless you are comparing in the same room. |
This was my theory on it too. |
I should probably say it isn't worthless, but one can't compare pjs that are in different environments. The room plays to big of a factor in determining ANSI.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sun Jun 23, 2013 5:15 am Post subject: |
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Yep, i knew exactly what youre saying here, to expand on it abit, what youre saying is the same projector with a fully masked screen in a room full of black curtains may very well produce higher readings than the same machine on a floating screen with light painted walls.
I dont believe the test is worthless, but there sure is influencing factors to consider, other than just the projector.
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stridsvognen
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| Posted: Sun Jun 23, 2013 7:41 am Post subject: |
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So it sounds like you Guys have lots of experience measuring ansi contrast in different rooms, Anyone like to tell a success story about how much they improved measured ansi contrast from changing the room.?
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sun Jun 23, 2013 10:43 am Post subject: |
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I have no experience measuring contrast, but quite abit in measuring lighting conditions.
However i have done work in my home to improve image quality, being that im still completing the interior, made it easy to see the effect of it all so far.
To start with, it was straight on a white wall, no masking, all white walls and a silver foil ceiling, now is a wall painted in an almost black colour, some excess black was put on the foil, and improvement was huge. Still need to paint the other walls and finish installing the ceiling, but i work 6 full days a week, so its hard to find time.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Sun Jun 23, 2013 10:49 am Post subject: |
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Should also add the curtains i use for masking 1.78:1 and 2.35:1 aspect. They make a huge difference all over again, watching 2.35:1 on a 5:4 screen was perfectly good, but although you could bearly even see the boarders top and bottom, they did add light to the room, which impeades contrast.
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sun Jun 23, 2013 3:34 pm Post subject: |
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| stridsvognen wrote: | | So it sounds like you Guys have lots of experience measuring ansi contrast in different rooms, Anyone like to tell a success story about how much they improved measured ansi contrast from changing the room.? |
I haven't taken measurements myself, but I have read the results from others that I trust. I know my friend Darin would go overboard by wearing black clothing when he took measurements. You can read his article on the subject in the link below.
http://www.hometheaterhifi.com/volume_13_2/feature-article-contrast-ratio-5-2006-part-1.html
I do agree with you about calibrating. Trying to do it by eyeometer can get you in the ballpark if you know what you are doing. You really need equipment to do it right though.
I can think of one definitive success story about changing the room with experiments. Guy Kuo ran some tests about ten years ago. He put a black curtain that he raised and lowered at the rear of the room to determine what effect it would have on ANSI. I believe he also tested the curtain on the side walls and ceiling.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Sun Jun 23, 2013 5:15 pm Post subject: |
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| stridsvognen wrote: | | Spanky Ham wrote: | | Comparing ANSI measurements are worthless unless you are comparing in the same room. |
Sure, but if there is enough feedback, you get a impression of whats normal, and maybe whats possible. |
No, what you get is a great exhibition of how a whole slew of variables impact a set of measurements. Different rooms, different screens, different meters, different experience levels... I explained this once already in one of the other threads. There are so many variables, any comparison becomes meaningless. Further, almost none of us have the equipment, expertise, or discipline necessary to measure some of these things in any meaningful, comparative way. ANSI contrast, or changes in ANSI contrast with most changes to the room? Forget it. I can try to measure it with my $200 meter, but what do you know about how I did it, how my meter was pointed, was the meter calibrated, how old is it, or do I even know what the hell I'm doing?
There are plenty of articles, written by well-known experts on these subjects. Reference those if you want to learn more. If you wanted to ask Craig, or Ken, or any number of other people, in a general sense, how these machines measure, and how that impacts the perceived image quality, that would also be interesting. But, trying to test ANSI contrast, in our own rooms, with amateur equipment... That just really won't add anything meaningful to the discussion. That's we talk about concepts and not actual numbers.
SC
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stridsvognen
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| Posted: Sun Jun 23, 2013 8:53 pm Post subject: |
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Ecrabb..
Is this something you have experienced from testing different gear screens and rooms and so on, or is it 2nd hand information you got from someone else.. or read about.?
Im very well aware of the rooms impact on the Picture, but im fishing here to hear if you Guys know what your talking about, or its just something you hear so often that its the truth.
Im not finished playing with this, but so far i have a idea that most people cant tell, not even close guess the measured ansi contrast in a setup.
I hear Guys changing from a CRT to a JVC and telling that the ansi contrast is much better..
I also hear that LC have better ansi than AC.. i know for sure in my setup here, thats not the case when measured with normal ansi contrast pattern ½ White ½ Black.
But looking the Picture i would bet my mothers life that the LC machine beats it big time.
So its something else whos different .
Marquee 8500AC Ultra 38:1
Marquee 9500LC Ultra 37:1
Then lets say they are close.. same screen same room same all just the projectors changed, both calibrated to gamma around 2.25
even the room is White it dont change the ansi when changing light output, it just elevates both Black and White keeping more or less the same ansi contrast im talking something like 10 vs 15fl
I just digged my JVC X50 out Again, and will measure it in the same room screen and so on..
Anyone want to guess the ansi nr on the JVC.? We all know its better right.?
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sun Jun 23, 2013 10:24 pm Post subject: |
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Read the article I linked to.
| Quote: | ANSI CR is much more room-dependent. It is different than On/Off CR as far as the effect of reflections around the room, because reflections from white areas that go around the room do fall on the black areas, whereas with On/Off CR, the full white image and full black image are only raised by their own reflections. If 20% of the light comes back and splits between the white and the black rectangles, each will be raised by about 10% of the original level of the white rectangles. For a projector providing 100:1 ANSI CR, raising both the white rectangles and black rectangles by 10% of the white rectangle's intensity would result in the brighter rectangles being 110% of their original values, and the darker rectangles being 11% (from 10% + 1%) of the original intensity of the white rectangles, for an ANSI CR of 10:1 just considering the first reflections that return.
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I admit I haven't done the testing, but I trust the testing that Darin has done. I know Darin has a completely black room that he has used to test a lot of pjs over the years.
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stridsvognen
Guest
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| Posted: Sun Jun 23, 2013 11:29 pm Post subject: |
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| Spanky Ham wrote: | Read the article I linked to.
| Quote: | ANSI CR is much more room-dependent. It is different than On/Off CR as far as the effect of reflections around the room, because reflections from white areas that go around the room do fall on the black areas, whereas with On/Off CR, the full white image and full black image are only raised by their own reflections. If 20% of the light comes back and splits between the white and the black rectangles, each will be raised by about 10% of the original level of the white rectangles. For a projector providing 100:1 ANSI CR, raising both the white rectangles and black rectangles by 10% of the white rectangle's intensity would result in the brighter rectangles being 110% of their original values, and the darker rectangles being 11% (from 10% + 1%) of the original intensity of the white rectangles, for an ANSI CR of 10:1 just considering the first reflections that return.
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I admit I haven't done the testing, but I trust the testing that Darin has done. I know Darin has a completely black room that he has used to test a lot of pjs over the years. |
As i wrote before, im aware of the rooms big impact on image, But in my room i have not been able to change ANSI contrast readings by raising light output, just did the test Again with my JVC.
And trust me the room is far from perfect.
20% of the light coming back seems like quite extreme situation, i cant coment on if the nr are right or not, ill just have to trust that. Ill not try make that setup.
Untill now i just see you Guys argue that there is no point in measuring ansi contrast in different setups, that its useless.. Well i think i can use it to get a good idea understanding whats important or not, and help me improve ANSI on my CRT.
Ill be calibrating some other projector setups around in near future, and ill do my own study, and math, and in the future ill document if 16:9 masking of the tube face on a LC crt will have effect on Ansi contrast.
Now i think i asked if anyone would help me with some Measurements, and havent gotten anything but coment on how useless that is.
While you Guys kepp writing about stuff you never bothered to check or confirm, ill use my time on some 1st hand experience WHO can help me understand and improve my PQ in the future..
I got the Nr on my JVC, to compare with the CRT.. Ill not bother to post it here like its meeningless.. So if anyone is curious.. you have to do the setup and testing in your own rooms.. 
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Jun 24, 2013 4:11 am Post subject: |
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Hey everything i posted was info i confirmed when i did the jobs!!
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Mon Jun 24, 2013 4:25 am Post subject: |
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| stridsvognen wrote: | Is this something you have experienced from testing different gear screens and rooms and so on, or is it 2nd hand information you got from someone else.. or read about.?
Im very well aware of the rooms impact on the Picture, but im fishing here to hear if you Guys know what your talking about, or its just something you hear so often that its the truth. |
Trying to do it ourselves is a waste of time. Neither one of us have the room, equipment, or expertise to properly measure ANSI contrast with any meaningful accuracy.
With all this "have you tested it, or have you just read it" talk, I would assume you'd also argue that a 9" LC machine isn't really any sharper than an 8" AC machine. All this stuff about 9-inch machines being sharper is all just something we hear so often that it's the truth, right? Oh, we can see it with our own eyes, and we've seen the MTF measurements measured by the experts with the equipment? Yep.
| stridsvognen wrote: | | Im not finished playing with this, but so far i have a idea that most people cant tell, not even close guess the measured ansi contrast in a setup. |
Can most people guess the numbers? Maybe not - not unless he/she were trained to index a "look" with a given ANSI contrast range. But, tell a 100:1 ANSI machine from a 300:1 ANSI picture? Yes, I'd bet money that's easily noticeable.
| stridsvognen wrote: | | I hear Guys changing from a CRT to a JVC and telling that the ansi contrast is much better.. |
It is. It's been measured numerous times over the years by experts with the right equipment, and the JVC is superior to a CRT in terms of ANSI. DLP is even better.
| stridsvognen wrote: | I also hear that LC have better ansi than AC.. i know for sure in my setup here, thats not the case when measured with normal ansi contrast pattern ½ White ½ Black.
But looking the Picture i would bet my mothers life that the LC machine beats it big time.
So its something else whos different .
Marquee 8500AC Ultra 38:1
Marquee 9500LC Ultra 37:1 |
Wait, so because you personally can't measure a difference in ANSI contrast between your two machines, everything ever written on the subject is wrong, and LC looking so much better... That must be something else. Do you realize that AC's horrible ANSI contrast is the whole reason LC was developed int the first place?
Of course, that's ridiculous from the get-go. If A) your CRT projectors are measuring an abysmal 38:1, and/or B) that an LC machine measures the same as an AC machine, then something is seriously wrong with your meter, your methods, or your room. Throw up a small point source like a small title or moon on the screen of the8500, and you'll see the big halo on the AC machine. That's ANSI contrast going to hell in a hand-basket.
| stridsvognen wrote: | Then lets say they are close.. same screen same room same all just the projectors changed, both calibrated to gamma around 2.25
even the room is White it dont change the ansi when changing light output, it just elevates both Black and White keeping more or less the same ansi contrast im talking something like 10 vs 15fl |
Are you serious? Room reflections making both dark and light brighter, so not changing the ratio? Think about what you're saying - the math isn't that complicated.
Let's use 100:1 for example... In a black cave. If the whites measure 10fL, at 100:1, the blacks measure about .1 fL. Now, let's say that setup is in a room and some white walls and ceiling put 1 fL back on the screen. The .1 black square then goes to 1.1 fL, while the white square goes 11 fL. Your in-room ANSI contrast just went from 100:1 in the cave to 10:1 in the white room. Now do you see why the room is so critical? Screen material and projector placement and even throw angle? It's ULTRA-critical, which is why people like Darin, Phelps and some of the other guys that were measuring this stuff years ago went to great lengths to black out the room, and why Darin even wore black clothes.
| stridsvognen wrote: | I just digged my JVC X50 out Again, and will measure it in the same room screen and so on..
Anyone want to guess the ansi nr on the JVC.? We all know its better right.? |
The way you're measuring it? I'm guess it will probably about the same as - or barely any better than - the CRT projectors. Once you measure that, we'll have established one thing with certainty: That DIY'ers who don't know what they're doing can't properly measure ANSI contrast and learn anything meaningful from it.
I really don't mean to be disrespectful, but it's absolutely mind-boggling to me that you're dissatisfied by the dozens of tests and the volumes that have been written on this subject, and would instead rather rely on your own inaccurate (at best) tests.
SC
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Mon Jun 24, 2013 4:30 am Post subject: |
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| stridsvognen wrote: | | While you Guys kepp writing about stuff you never bothered to check or confirm, ill use my time on some 1st hand experience WHO can help me understand and improve my PQ in the future.. |
With all due respect, given the numbers you posted above, all you're confirming is that you can't reliably measure ANSI contrast.
| stridsvognen wrote: | | I got the Nr on my JVC, to compare with the CRT.. Ill not bother to post it here like its meeningless.. So if anyone is curious.. you have to do the setup and testing in your own rooms.. |
Nice. So, while you insist everyone should reject (and even challenge) all the common knowledge based on well-known tests by well-respected experts, you won't post your own results. Interesting.
SC
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Jun 24, 2013 5:02 am Post subject: |
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Youre getting abit fanatical here arent ya Crabb?
Jokes aside though, what he says is correct, and you really need to work on your room before you worry about anything else. Paint all the walls black or put up black sheets.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Mon Jun 24, 2013 5:11 am Post subject: |
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| CasetheCorvetteman wrote: | | Youre getting abit fanatical here arent ya Crabb? |
Nah, not at all. My mind is just blown. I can't understand why anyone would cast aside years of hard work by well-respected professionals and enthusiasts alike, and instead say, "Bah. I'll measure it myself." Then, when he did, and his ANSI measured very poorly, he said, "See, ANSI isn't even any different between AC and LC... Must be something else."
 
I'm all for DIY and learning is great - I've been learning all I can about this hobby for more than ten years. But, I also realize when certain things are better left with more expertise and better equipment than I have, AKA reinventing the wheel.
SC
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mx83toy
Joined: 14 Dec 2012
Posts: 322
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| Posted: Mon Jun 24, 2013 6:08 am Post subject: |
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ohh and where are those screenshots???im currently fixing up a 8110 ultra (will be 8500 soon  ) and cant wait to see what to expect as im coming from a Cine 7.... 7" ES
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