Page 1 of 8 12345 ... LastLast
Results 1 to 10 of 73
  1. Collapse Details
    Dynamic Range test (real one)
    #1
    Red Leader Jannard's Avatar
    Join Date
    Dec 2005
    Location
    WA and in an airplane...
    Posts
    613
    Default
    This test was done by Graeme Nattress at the RED factory today. Great care was taken to perform the test accurately. The data clearly demonstrates 11 1/3 stops of dynamic range... or greater than 66db. Just as advertised back at NAB 2006.



    A Stouffer T4110C calibrated 41 step Transparent Step Wedge Chart was shot at F4.0 on the RED Frankie prototype camera.

    The RAW sensor data was taken into REDCINE Prototype, and demosaiced. At no time was any noise reduction or data manipulation applied.

    The data analysis mode of the REDCINE Prototype was used to align 41 sample areas with the 41 steps of the wedge chart. Individually red, green and blue averages were calculated for each of the sample areas. Log base 2 was taken of each average.

    The graph plots the log green averages for each sample area against the calibrated value for each wedge in the test chart.

    Graeme Nattress


     

  2. Collapse Details
    #2
    Cross-Examiner Emanuel's Avatar
    Join Date
    Oct 2005
    Posts
    4,664
    Default
    Jim -- useful/real(ly one) and fair(ly) productive indeed

    EDIT -- Poi Boy had the true 11 figure!
    Last edited by Emanuel; 12-13-2006 at 05:25 PM.
    RED ONE @home
    #111
    Emanuel & Co's RED ONE
    #647
    RED ZOOM LENSES
    #156
    #157
    RED 300mm LENS
    #82
    Who am I?

    * LINK *
    ** IMDb **


     

  3. Collapse Details
    #3
    Senior Member Poi Boy's Avatar
    Join Date
    Jan 2006
    Location
    Kailua, Hawaii
    Posts
    313
    Default
    That is great ! mine goes to 11; well, actually 11 and a 1/3.
    Hopefully this will quite some of the whiner, snobs at cml. On second thought, it won't but who cares, mine goes to 11.
    Aloha
    -A
    RED # 086 #1031, ZOOM#38


     

  4. Collapse Details
    #4
    Member
    Join Date
    Oct 2006
    Location
    Ireland
    Posts
    46
    Default
    Quote Originally Posted by Jannard
    This test was done by Graeme Nattress at the RED factory today. Great care was taken to perform the test accurately. The data clearly demonstrates 11 1/3 stops of dynamic range... or greater than 66db. Just as advertised back at NAB 2006.



    A Stouffer T4110C calibrated 41 step Transparent Step Wedge Chart was shot at F4.0 on the RED Frankie prototype camera.

    The RAW sensor data was taken into REDCINE Prototype, and demosaiced. At no time was any noise reduction or data manipulation applied.

    The data analysis mode of the REDCINE Prototype was used to align 41 sample areas with the 41 steps of the wedge chart. Individually red, green and blue averages were calculated for each of the sample areas. Log base 2 was taken of each average.

    The graph plots the log green averages for each sample area against the calibrated value for each wedge in the test chart.

    Graeme Nattress

    Well, thats fantastic. I have no idea what you are talking about, but I see over 11 stops and I understand that are gud.

    Out of curiosity - how does that compare to modern film neg?

    In English, please


     

  5. Collapse Details
    #5
    Senior Member Brook Willard's Avatar
    Join Date
    Sep 2006
    Location
    Orange, CA
    Posts
    502
    Default
    This is GREAT, thank you guys so much for doing this test for us. Any chance of seeing the frame that the range was judged from?
    "I've heard that this project is impossible... hehe" ~ Jim Jannard
    The Pursuit of Happyness


     

  6. Collapse Details
    #6
    Senior Member
    Join Date
    Jul 2004
    Location
    home, USA
    Posts
    136
    Default
    Great news, thanks for posting this chart! I'm curious... since the T4110C wedge has 41 discrete steps, I would expect to see steps or individual points on the graph. I assume the continuous line shown is drawn between the specific density values on the wedge (nominally 1/3 step apart).

    At the bottom left region of the plot, it appears the response from approximately 2.5 to 3.2 stops is quite flat (horizontal line). Should that region be included as part of the effective dynamic range?


     

  7. Collapse Details
    #7
    Red Team Graeme_Nattress's Avatar
    Join Date
    Apr 2005
    Location
    Ottawa, Canada
    Posts
    1,135
    Default
    The chart is calibrated in optical density, from which the horizontal axis is defined. Yes, it is a touch flat there, but when you analyse the data, there's still information there that hasn't quite been swamped by noise. The graph scale would have to be bigger to see that, and being log to match the power law nature of optical density doesn't help.

    Remember this is our first such chart, and we'll be using the tools as an internal reference as we work on the sensor to ensure we deliver great characteristics.

    We think this method of measuring dynamic range is so much less succeptable to error than the series of 1 stop charts, which has a large opportunity for human error in both setting up of the tests and analysis. Our analysis is performed on the raw demosaiced data, in a very controlled environment, with no use of external software to measure an image, where you're never quite certain how the numbers are created, which makes it repeatable and accurate.

    Graeme
    Last edited by Graeme_Nattress; 12-13-2006 at 06:46 PM.
    www.nattress.com - Film Effects and Standards Conversion for FCP
    www.red.com - RED - 4k Digital Cinema Camera


     

  8. Collapse Details
    #8
    Senior Member
    Join Date
    Apr 2006
    Posts
    571
    Default
    This is very encouraging and much better than previous results. Would anyone at Red mind repeating the same test using another camera that the outside world can use as a reference? Any other camera?

    Alternately, please do something like DPReview does when they test dynamic range using a Stouffer wedge. They post images and give more info than just a simple graph.

    I do have a serious question, though, for future cameras: is there anything stopping you from putting little dots of ND paint on every fourth sensor or so and then using info from those darker pixels when the highlights start clipping? You could afford to give up some resolution for this because you have so much to start with.

    I'd much rather have a 3K Red with great dynamic range than a 4.5K Red with only average dynamic range. I know I'm going to get mocked for this and I know the Fuji SR high-dynamic range system didn't do that well in still cameras. Still, dynamic range is so important for moving pictures.

    Thanks!

    Bruce


     

  9. Collapse Details
    #9
    Ban Me Please! insanityfw's Avatar
    Join Date
    Oct 2004
    Location
    I have no idea, but it's hot as hell.
    Posts
    1,300
    Default
    I don't know exactly what it all means, but I also know that 11 stops is very, very good.

    I do know this.... You'll have to pry my reservation spot from my cold, dead hands if you want it.
    I know how to do it. You just wouldn't know it from the way that I do it.


     

  10. Collapse Details
    #10
    Senior Member
    Join Date
    Apr 2006
    Location
    Toronto, Canada
    Posts
    253
    Default
    How much of the dynamic range is useful?

    From the Origin images up on CML (well practically every camera on the comparison tests there), the highlights tend to exhibit color shifting. Is there some metric/test where this can be evaluated? Dalsa is pretty open about their camera doing 10-12 stops, since those last two stops exhibit color shifting (my understanding anyways).

    Perhaps putting error bars on there would be helpful, as it would indicate the amount of noise. And presumably it's possible to tradeoff noise versus grayscale tracking (i.e. apply processing to achieve good grayscale tracking; this can magnify noise at certain points of the slope).
    Last edited by glenn chan; 12-13-2006 at 07:27 PM.


     

Page 1 of 8 12345 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •