Page 3 of 8 FirstFirst 1234567 ... LastLast
Results 21 to 30 of 73
  1. Collapse Details
    #21
    Senior Member Anders Holck's Avatar
    Join Date
    Apr 2005
    Location
    Copenhagen, Denmark.
    Posts
    966
    Default
    Ok great. Seems like a great tool with the automation.

    But wouldn't you want to rate the camera as 5000k native then as that will boast the max dynamic range and color fidelity.

    Also I can't really get why some wouldn't want to rate a cameras sensitivity. Most DSLR's seem to have 10 1/2 stop of RAW dynamic range and puts normal exposure about 4 1/2 stops below saturation, which translates to an over exposure latitude of about 2 1/6 of a stop, over the white patch. Wouldn't you want to do something alike with the RED.
    CodeMonkey of P2Genie (Mac), FCP Rescue and....The Dane Hack

    skype: a_holck


     

  2. Collapse Details
    #22
    Red Team Graeme_Nattress's Avatar
    Join Date
    Apr 2005
    Location
    Ottawa, Canada
    Posts
    1,135
    Default
    Anders, we can choose what is native kelvin for the camera. Would you like 5000k?

    We can rate a sensitivity or iso, but you can rate it yourself too, picking how many stops above and below you want. Looking at DPReview, DSLR's don't have 10.5 stops though - but again, hard to rate given that white clip is easy to spot, but black detail into noise floor is hard to determine.

    Graeme
    www.nattress.com - Film Effects and Standards Conversion for FCP
    www.red.com - RED - 4k Digital Cinema Camera


     

  3. Collapse Details
    #23
    President/Founder Jarred Land's Avatar
    Join Date
    May 1975
    Location
    California
    Posts
    87,437
    Default
    yes indeed.. great post Glen.

    Filters are great for balancing things out, but as Graeme mentioned, putting on a color filter always results in a loss of light from the reduced transmission optically of the filter..

    So you kinda defeat the advantage because by shifting down the highlights with a filter you also push down the lows past the black clip point.

    Thats why DSP's use curves, and even better when they use curves in individual channels, to roll off highlights.

    I think the Wedge test should be the new standard for digital DR tests.. its only a $40 chart (calibrated!!), is backlit which is usually easier to get more accurate results, and is a whole lot easier then the classic method with alot less margin for error.

    As Graeme mentioned during the shoot today, ramping stops on lenses and using ND's really is testing the accuracy of the markings on the glass and the accuracy of the ND's.
    .


     

  4. Collapse Details
    #24
    Red Team Graeme_Nattress's Avatar
    Join Date
    Apr 2005
    Location
    Ottawa, Canada
    Posts
    1,135
    Default
    That's right Jarred. I mean, exactly how accurate are those marks on the lens, and how accurate and repeatable can you set them. Given each camera tested on the CML graph used a different lens, I can see this as a big source of error. With this method, the accuracy of the lens' markings is eliminated, as is the user error of setting the lens to such marks. As you get down into the shadows, you're trying to see if there's still detail not being masked by sensor and quantisation noise. This is not easy. Practically any source of error will show up as distortion of the curve in the shadows. I'm not saying our test has no errors, but it was very repeatable and we did try to eliminate as many sources of error as possible, including full automation of the measuring of the chart.

    Also, I think this chart is also going to show you the minimum dynamic range, rather than a more liberal range which the multiple shot method contributes to, as pointed out by Adam Wilt.

    Graeme
    www.nattress.com - Film Effects and Standards Conversion for FCP
    www.red.com - RED - 4k Digital Cinema Camera


     

  5. Collapse Details
    #25
    Senior Member
    Join Date
    Apr 2006
    Location
    Toronto, Canada
    Posts
    253
    Default
    Filters are great for balancing things out, but as Graeme mentioned, putting on a color filter always results in a loss of light from the reduced transmission optically of the filter..
    That's ok since most of the time you will have enough light. Where you don't have enough light, it's not a big deal to ditch the filters to get the most low light possible.

    2- What if you could change the color filters on the bayer sensor itself? (since each photoshop needs a color filter over it.)

    In low light situations, perhaps you could optimize sensitivity by using filter choices that let in more light. i.e. the Sony F900 lets in a lot of infrared-ish light to increase sensitivity.

    And for the color accuracy nuts, I'd like to see to a RGB+E filter option please. (Although Sony likely holds some sort of patent for that; it is arguably an obvious improvement though, if you're trying to reproduce the appropriate CIE CMFs).
    On the other hand, I've never seen accurate color... so even if you do achieve it, it may be that no one cares.

    FYI: Accurate color is really hard even if it's your eyes looking at the real world... look up metamerism.


     

  6. Collapse Details
    #26
    Red Leader Jannard's Avatar
    Join Date
    Dec 2005
    Location
    WA and in an airplane...
    Posts
    613
    Default
    Glenn... sleep tight. Graeme is awake.

    Jim


     

  7. Collapse Details
    #27
    Senior Member Poi Boy's Avatar
    Join Date
    Jan 2006
    Location
    Kailua, Hawaii
    Posts
    313
    Default
    The following is a CML post from Jim. You continue to impress and inspire me with your mad skills.


    " s1st... my apologies (again) for stirring up a sh$tstorm.

    We have struggled from the beginning here at CML. My introduction to Geoff was rocky. I'm betting we would do much better if we could start over.

    I had hoped for constructive criticism when I 1st posted here. No one told me I needed a helmet. We really don't mean to be a disruptive force on this board, but it seems we are. Maybe it is our frustration showing. We recently posted, with Geoff's assistance, many test shots of green screen work done with the help of David Stump. I don't recall one post of feedback about the quality of the images. The next thing that happens is an exposure latitude chart that puts us below consumer cameras. You might imagine your reaction if this was your project and the results of that chart did not match up with the results you had in-house.

    The testing of dynamic range is best done on a single exposure. The Stouffer T4110c is the best tool. If you take multiple exposures while adjusting the f-stop and using neutral density filters that are not calibrated... the results are influenced by several non-sensor factors. The DSLR world has already embraced this testing methodology for good reason. And like it or not, these are high speed DSLRs.

    We set up our own lab for this test. It is easy and accurate. Graeme spent a whole day automating the results process. There is no speculation to the results. Our suggestion is that David Stump come to RED to supervise the process (we invited him today). We cannot tell anyone what to do with their testing process but we encourage all interested to investigate this methodology.

    It sounds like Jessica would delete the "future cameras" from this list. I'm OK with that. We will be done soon. In some ways it might be better to wait until our project is finished before discussing it.

    Geoff... I appreciate you hosting the RED images. I appreciate your early skepticism at NAB. It has motivated me to not only finish the project, but to deliver more than we originally promised. I do not want you to grovel, anymore than I want to. You have built a great home here. It is possible that there is just not a room for us. We are as passionate about this project as cinematographers are about their work. Everyone wants their work to be shown in the best light.

    Jim "

    Aloha
    -A
    RED # 086 #1031, ZOOM#38


     

  8. Collapse Details
    #28
    Senior Member Jim Arthurs's Avatar
    Join Date
    Mar 2005
    Location
    Colorado Springs, CO
    Posts
    840
    Default
    I hope having to deal with this little "crisis" hasn't slowed REAL work on the camera, or tied up the RED Team. Testing is useful, but wouldn't it all be better if done on, at least, the next generation of RED test platform?

    Won't critics simply suggest that whatever results are obtained today not be reflective of the 2nd and 3rd generation of RED prototypes? I remember something similar just last year with the HVX200 and results of first beta units compared to shipping ones...

    I'll say it again, you guys should just go information DARK until those handful of field ready prototypes are pulling in footage. All this drama from the "full disclosure" of process seems ultimately distracting from the real job at hand...
    Jim Arthurs


     

  9. Collapse Details
    #29
    Red Leader Jannard's Avatar
    Join Date
    Dec 2005
    Location
    WA and in an airplane...
    Posts
    613
    Default
    Jim... this is a valid point of view. We do have our hands full. And the drama is distracting. But we feel obligated to keep our reservation holders informed. The "open development" process can't just be when it is convenient to us. We are committed to it, for better or worse.

    Jim


     

  10. Collapse Details
    #30
    Default
    Quote Originally Posted by Graeme_Nattress
    . I mean, exactly how accurate are those marks on the lens, and how accurate and repeatable can you set them.
    Graeme
    Graeme,

    Cooke & Zeiss lenses are indivulally calibrated for T stops & Focus marks, one of the reasons they are expensive.

    Stephen


     

Page 3 of 8 FirstFirst 1234567 ... 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
  •