1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Which do you think is the *actual* possible appoximate contrast ratio of projectors?

Discussion in 'Projectors, Screens & Video Processors' started by Stuart Wright, Sep 28, 2005.

?
  1. 200:1

    6 vote(s)
    4.7%
  2. 400:1

    9 vote(s)
    7.0%
  3. 800:1

    12 vote(s)
    9.4%
  4. 1,200:1

    13 vote(s)
    10.2%
  5. 1,600:1

    6 vote(s)
    4.7%
  6. 2,000:1

    25 vote(s)
    19.5%
  7. 5,000:1

    26 vote(s)
    20.3%
  8. 10,000:1

    31 vote(s)
    24.2%
  1. Stuart Wright

    Stuart Wright
    AVForums Founder Staff Member

    Joined:
    Jan 24, 2000
    Messages:
    13,821
    Products Owned:
    6
    Products Wanted:
    2
    Trophy Points:
    167
    Location:
    Birmingham, UK
    Ratings:
    +9,559
    Joel Silver of the ISF is a well respected character in the AV industry. He's done a lot for educating people about the science of home cinema.
    According to Joel, which, approximately, is the best achievable contrast ratio from home video projectors?
    If any of you guys actually know the answer, please don't spoil this poll by answering.
    Vote away.
     
  2. shahedz

    shahedz
    Well-known Member

    Joined:
    Apr 26, 2005
    Messages:
    10,288
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +1,225
    Hi stuart , will you tell us the answer? if so when? would like to know if i answered correctly :thumbsup:
     
  3. eviljohn2

    eviljohn2
    Well-known Member

    Joined:
    Jul 8, 2002
    Messages:
    7,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Near London.
    Ratings:
    +208
    Is this just for consumer projectors? Some of the big ones used for conferences etc are far more powerful. :)
     
  4. LV426

    LV426
    Administrator Staff Member

    Joined:
    Jul 14, 2000
    Messages:
    12,789
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Somewhere in South Yorkshire
    Ratings:
    +4,987
    ....and in any case, brightness and contrast aren't necessarily related.
     
  5. eviljohn2

    eviljohn2
    Well-known Member

    Joined:
    Jul 8, 2002
    Messages:
    7,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Near London.
    Ratings:
    +208
    But surely the maximum achievable home contrast is exactly the same as those which aren't necessarily practical for home use just yet. It's only a matter of time though. :)
     
  6. Tejstar

    Tejstar
    Well-known Member

    Joined:
    Dec 4, 2002
    Messages:
    22,501
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Location:
    London
    Ratings:
    +995
    I say 10,000:1, although it's hard to imagine this! I imagine it's a way off though...
     
  7. Stuart Wright

    Stuart Wright
    AVForums Founder Staff Member

    Joined:
    Jan 24, 2000
    Messages:
    13,821
    Products Owned:
    6
    Products Wanted:
    2
    Trophy Points:
    167
    Location:
    Birmingham, UK
    Ratings:
    +9,559
    Ok, here is the answer....

    200:1

    Any facts and figures stating any contrast ratio greater than 200:1 are marketing BS.
    One way the marketing depts. fudge this is by measuring the contrast ratio between the machine when doing it's brightest possible output vs when it is switched off!!! Not real world figures.

    The Human eye can't see beyond 800:1 anyway, so anyone quoting contrast ratios beyond this is like a speaker manufacturer quoting output beyond 20KHz. E.g. our speakers output 20Hz to 40KHz. What's the point? Nobody can hear above 20KHz and most people are below 15KHz. Nobody can see beyond 800:1.

    But the marketing depts. get away with it because people don't know any better.
    Well now you do.

    So, the next question is...
    What, approximately, is the contrast ratio of film? I.e. projected film at the cinema?
     
  8. Timbo21

    Timbo21
    Well-known Member

    Joined:
    Dec 23, 2004
    Messages:
    4,471
    Products Owned:
    2
    Products Wanted:
    2
    Trophy Points:
    106
    Location:
    London
    Ratings:
    +263
    This makes sense, since I saw the Hitachi LCD 7200 TV & it definitely seemed to have better contrast than my Infocus 7205 projector, which is quoted at 2200:1. Whereas, LCD's seem to be 800:1 max, & the decent ones seem to be in the region of 500:1 when measured by the likes of HCC.

    This I def. want to know. :)
     
  9. Arkham Insane

    Arkham Insane
    Active Member

    Joined:
    Apr 17, 2005
    Messages:
    441
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    21
    Ratings:
    +13
    unbelivable! whats more striking to think about is that 'if' this fact is true then will this piece of info shake the projector buying world (hmm) or just sink away out of memory?
    Will i be spending more money next year after comparing the contrast ratios of two otherwise equal projectors?
     
  10. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    I've actually measured my Optoma H78 at 2707:1 and my NEC HT1000 at 2000:1 (both at D65), so I beg the question where does 200:1 come from...

    Film in general is around 2000:1 unless some procesing of the print is made to increase it - usually by improving the ability of the black celuloid using a nitrite process, and this may give you around 4000:1.

    That might all be a moot point since the film/Hi Def cameras that record this to film or tape are only capable of 1000:1. Any higher CR than that will just improve the black level from a given white level, and will not reveal any more shadow detail.

    Gary.
     
  11. ROne

    ROne
    Active Member

    Joined:
    Dec 21, 2000
    Messages:
    778
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +7
    The eye only has 800:1 CR ???

    I would like to level bet the difference between a bright day and a dark night is more than 800:1, at least to the extent what your eye will resolve.
     
  12. squibbly

    squibbly
    Active Member

    Joined:
    Oct 8, 2004
    Messages:
    329
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +4
    Aren't we getting ANSI CR (which has a much lower reading) confused here with On/Off CR (which is the one quoted by display manufacturers) here?

    Squibbly
     
  13. fortean

    fortean
    Active Member

    Joined:
    Nov 28, 2004
    Messages:
    823
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    Chorley
    Ratings:
    +71
    But how do you get to see a bright day and a dark night at the same time?
     
  14. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    With a figure of 200:1 Joel Silver certainly does seem confused. Have you got a direct link to Joel's article Stuart where he quotes that number?

    It's not necessarily those conditions, but those like it, such as a bright full moon at night with an unlite scene in the same field of view, bright daylight scene with a dark alley in say New York, a dark room with a door open to a bright day etc etc

    The eye is capable of resolving contrast of millions to one, only not al at the same time, and I'm pretty sure the eye/brain combination can resolve a lot more contrast detail than 200:1. If you have a projected image with say 3000:1 CR range being displayed, and then introduce some light into the room such as by opening a window or turning a light on, the CR will decrease to just a few hundred at most, and the image will lose depth and detail. You will see that quite easily.

    A figure of 200:1 ANSI is pretty much average for a light controlled room with dark walls and no ambient. It's also probably only achievable by DLP as most other projection technologies aren't capable of as good ANSI as DLP, and are limited by the lens and or display array properties.

    Gary.
     
  15. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
  16. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    Forgot to mention. Many DLPs can easily achieve in excess of 2000:1 @D65, and CRTs can achieve in excess of 8000:1, depending on whether or not they have been set for good shadow detail, or prolonged total fade to black, in which case the CR can be up to infinity - zero light output divided into whatever the white level is will always be infinity. As it is, anything over approx 3500:1 doesn't appear to reveal any more shadow detail - in fact I wouldn't be surprised if it's much lower - say 1000:1 as suggested by the limitation of the movie cameras themselves.

    Gary.
     
  17. Stuart Wright

    Stuart Wright
    AVForums Founder Staff Member

    Joined:
    Jan 24, 2000
    Messages:
    13,821
    Products Owned:
    6
    Products Wanted:
    2
    Trophy Points:
    167
    Location:
    Birmingham, UK
    Ratings:
    +9,559
    Joel silver of the ISF. He discussed it at his 1 day seminar.
    That guy does know what he is talking about.
    What we need to discuss here is the conditions which matter, i.e. in your home cinema.
     
  18. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    The readings were taken in my home cinema under normal viewing conditions.

    I know Joel knows his stuff, but I wonder if someone got the wrong end of the stick regarding what projectors are capable of - if he was indeed talking about ANSI, then he is not far off what is capable in a good room. On/Off CR is a different kettle of fish altogether.

    The poll didn't differentiate between on/off and ANSI, which it should have done if it was referring to ANSI. The ANSI in my grey room is approx 100:1 but I'll be trying to improve that with black felt in the near future, and will of course post the results here.

    Gary
     
  19. lw32

    lw32
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I don't see the point of on/off contrast (except for marketing purposes).

    You won't ever see the brightest white and the deepest black on screen at the same time, so who cares what outrageous CR manufacturers come up with?

    ANSI contrast is much closer to reality, but it's harder to impress someone with 200:1 than 10000:1, even if it is more accurate.

    CR figures should reflect what I see on the screen, not the on/off extremes which are completely useless.
     
  20. Jeff

    Jeff
    Well-known Member

    Joined:
    Jul 13, 2000
    Messages:
    5,489
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Basingstoke
    Ratings:
    +256
    Both on/off and ansi contrast are fairly important, CRT's don't have great on/off but they still perform very well overall as far as contrast is concerned. Also on /off doesn't mean full on vs switched off, if it did you would have infinite contrast.
     
  21. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    On/off determines your black level for a given white level - so if you have 12ft lamberts at full white, and 2000:1 on/off CR (average DLP), your black level is 0.006ft lamberts which is the best black you can ever display (such as a full blackout or night scene). If your on/off CR is 8000:1 like a CRT calibrated for good shadow detail, then the black level will be 4 times blacker at 0.0015ft lamberts, so on/off is very important for black level. You can dim the lesser capable CR machine down using a filter, but then you end up with very good blacks and a very dim image. It's quite possible (and probable) that a scene may require the full range of the display, such as with a full moon in a night scene, or a space scene with a brightly lit space ship interior in view.

    Contrast range is important for rendering shadow detail. If the black level is poor and the CR is low, you will be losing detail where shadows should be visible. This is very obvious with some older low on/off capable LCDs which look very grey when displaying black and do not display shadow detail very well. They can look very 'flat' because of it.

    ANSI capability is important for showing bright and shadow detail in the same frame at the same time. CRTS have low ANSI capability because of their lenses (bright parts contaminate the black parts due to lens light scatter), but have higher on/off CR and still produce what many consider to be the best displays available.

    Even if the source contains a range of just 1000:1, the higher CR machine will produce the better blacks with the same white level, so to say higher CR is useless isn't really true.

    Gary.
     
  22. lw32

    lw32
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Contrast is the ratio between white and black so why test them separately? On/off contrast does not exist in the real world, i.e. normal viewing conditions. I'm sure you can get deep blacks, or brilliant whites, by sacrificing the other but that is not practical.

    Oh, I didn't say higher CR is useless, but misleading CR figures are. on/off contrast has become a joke. I mean, the new dynamic iris LCD PJs are suddenly claiming a three-fold improvement in contrast. I hope they have inky blacks with the CR numbers being thrown around.
     
  23. fraggle

    fraggle
    Member

    Joined:
    Dec 11, 2002
    Messages:
    1,441
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Milton Keynes
    Ratings:
    +29
    If that was the way they tested them they would quote infinite CR from even the dimmest output projector. :)

    That 200:1 figure is BS.

    How has he measured it? I would hazard a guess using his own method, I bet specifically designed to produce extremely low figures to get people into his "controversial" seminars.

    Right... the human eye still by far exceeds any video pickup device for low light level resolution, and adapts from blindingly bright light to very near pitch black, and we can always distinguish shades at either of those extremes (trying to do so looking at very bright things, e.g. the sun, still works fine but can cause permanent damage)

    Sorry, I really do believe all these figures quoted by this guy aren't real in my world and only exist as a talking point, obtained using "odd" measurement techniques.

    Now I know you're trolling! Shame on you!

    Frequency outputs over the hearing limit of the listener still produce effects *on* the portons of music we can hear. A 15KHz tone can be a pure sine wave, or a distorted wave, and we can hear that difference. The distortion comes from higher frequency elements, so take those away and you've lost all the "feeling" of the instruments.
     
  24. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,309
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,021
    I couldn't agree more. Most figures are for hugely mal-adjusted settings and not taken at D65 so are as you rightly say, pretty much useless. If you reduce the advertised lumens and contrast figures by 40% then you're much closer for out of the box settings.

    Even those figures are for an uncalibrated machine and real figures are much less. It's a reasonable way to get better contrast capability in real terms, provided it's transparent in operation and the gamma adjustments are the same, otherwise it can become just another visible artefact that can be distracting.

    I'd still like to see a transcript of Joels comments to see in which context he had mentioned the figure of 200:1, but with Stuarts later comments of taking the room into account it ceratinly sounds like ANSI CR and not on/off.

    Manufacturers could give ANSI CR figures, but that would have to be in a black hole so that it is a measure of the pj and not the room it is in.

    Gary.
     
  25. ROne

    ROne
    Active Member

    Joined:
    Dec 21, 2000
    Messages:
    778
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +7
    You don't but the eye does have the capacity to deal with both and will give your widest possible latitude.

    For instance, I was out shooting a promo the other day, super bright day and caravans,nightmare. No budget or time to light outside ...

    So you end up with a correctly exposed caravan on a very sunny day and everything in the forest and lake in the background all crushed to black. The difference between the two intra scene were staggering, and with a camera only capable of 7 stops of latitude you've not got much to play with.

    Real world you should have big intra-scene contrast ( latitude,) and big on-off contrast ratio (sensitivity) . You need both, I would imagine that a camera is pretty analagous to a projector.
     
  26. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,053
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,130
    I guess it depends how he's working out the contrast .
    The intensity range ( the number of seperate detectable intensity variations a piece of negative can record is generally regarded as being 1000 and its not a linear distribution.

    However on transfer to print this is liable to be down to about 700 as everything above 685 is "headroom" and only becomes visible if its printed down on transfer to print ( a common practice for perceptually increasing lower intensity detail by overexposing on capture a couple of stops..or more to push the lower intensities into a more sensitive part of the negative response curve and then printing the resultant negative down to restore black level but give increased tonality in the lower intensities without the whites visibly getting darker) also one reason why projected film does not need a very low black level to still appear pleasingly contrasty ...unlike video).

    Intensity range to differentiate from contrast.

    Video is regarded as having an intensity range of about 100 I think from memory ( that is recordable intensity variation from black to white). Probably why the IRE scale is marked out in 100 incriments thinking about it.

    When its displayed its essentially stretched out on a higher contrast display to make it pleasing to the eye. Video benefits from being displayed over a large contrast range (its critical to making it work). Film can be displayed with a comparatively low contrast given its intensity range and still be percieved as having nice contrast levels.
     
  27. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,053
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,130

Share This Page

Loading...