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this cam good for vfx?

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  • this cam good for vfx?

    Thoughs on epic vfx with this cam ? Or not meant for that
    ?

  • #2
    I would think this should be one of the BMC's strong points. Apart from the EPIC and the ALEXA, I'm not sure many cameras would be clearly better than this one for green screen. 2.5K RAW should be a great advantage here.
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    • #3
      I routinely use VFX and the RAW shooting is what attracts me to this camera.
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      • #4
        I think for those like me with average pockets, it's a dream come true for VFX

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        • #5
          The only issue might be the rolling shutter. I say "might" because we don't really know how severe it is.

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          • #6
            In reality, no I don't think this camera is designed for VFX. If you are looking for green screen work, then yes this camera will perform fine but not to the extent that you are expecting. 2.5K resolution, even at RAW, is not what will make a difference in a chroma key situation. For green screen work the most important thing is the chroma resolution. Even though this is a 12bit RAW camera, that does not make it 4444 chroma. In fact, after the debayering, the chroma resolution will be above 4:2:0, but not quite 4:2:2. Barry Green has written extensively on this subject on this website, just do a search for his posts and you should find it pretty quickly.

            Having said that, that does not mean that you can't get a good key out of a 4:2:0 camera, as many people have done lovely chroma key work with a 5/7D, but you have to understand that is pretty much what you are doing with the BMCC. The RAW recording gives you more latitude to use for grading in post and while this is indeed great, that does not translate to better VFX. Even BM will tell you, like they told me at the NY show, this camera is best suited to those who had been using, or considering switching to, DSLR's. Its main focus is towards feature or short narrative film work, episodic TV or web production, or commercials. Its biggest advantages are in its dynamic range, luma resolution (which when debayered will give you a pretty much perfect 1080p), and its design as a true cinema camera. Again, it's simply not made for VFX.

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            • #7
              IIRC, Barry estimated a 700,000 times improvement in my green screens over my 7D.

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              • #8
                Originally posted by Matthew Sonnenfeld View Post
                In reality, no I don't think this camera is designed for VFX. If you are looking for green screen work, then yes this camera will perform fine but not to the extent that you are expecting. 2.5K resolution, even at RAW, is not what will make a difference in a chroma key situation. For green screen work the most important thing is the chroma resolution. Even though this is a 12bit RAW camera, that does not make it 4444 chroma. In fact, after the debayering, the chroma resolution will be above 4:2:0, but not quite 4:2:2. Barry Green has written extensively on this subject on this website, just do a search for his posts and you should find it pretty quickly.

                Having said that, that does not mean that you can't get a good key out of a 4:2:0 camera, as many people have done lovely chroma key work with a 5/7D, but you have to understand that is pretty much what you are doing with the BMCC. The RAW recording gives you more latitude to use for grading in post and while this is indeed great, that does not translate to better VFX. Even BM will tell you, like they told me at the NY show, this camera is best suited to those who had been using, or considering switching to, DSLR's. Its main focus is towards feature or short narrative film work, episodic TV or web production, or commercials. Its biggest advantages are in its dynamic range, luma resolution (which when debayered will give you a pretty much perfect 1080p), and its design as a true cinema camera. Again, it's simply not made for VFX.
                Isn't this also true of the Alexa and Epic at their intended resolutions?

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                • #9
                  Originally posted by Matthew Sonnenfeld View Post
                  For green screen work the most important thing is the chroma resolution.
                  Well, then let's do the math: The raw image is a 2432 x 1366 bayer pattern, which gives an effective chroma resolution of 1216 x 683 = 830528. 1080p at 4:2:2 (which is usually considered pretty excellent for green screen) has an effective chroma resolution of 960 x 1080 = 1,036,800. So, the bmc's raw image is not quite as good as 1080p 4:2:2, but both are much better than 1080p 4:2:0 (960 x 540 = 518,400). Also take into account the lack of compression artifacts in the the raw image and the BMC starts to look pretty good.

                  Long story short, if you are getting good enough results from 1080p 4:2:0, then the BMC's image should be significantly better, at least on paper.
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                  • #10
                    Originally posted by Tzedekh View Post
                    The only issue might be the rolling shutter. I say "might" because we don't really know how severe it is.
                    Indeed, this is the main reason that I have not pre-ordered yet. Keying and compositing BMC footage should be a snap, but if the rolling shutter distortion is very strong, then it could make motion tracking problematic.
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                    • #11
                      Originally posted by Wesley Byram View Post
                      Indeed, this is the main reason that I have not pre-ordered yet. Keying and compositing BMC footage should be a snap, but if the rolling shutter distortion is very strong, then it could make motion tracking problematic.
                      It's been rumored that the BMC's sensor is the BAE/Fairchild CIS2051, which has a global-shutter mode. As present, the BMC's sensor has a rolling shutter, and even if it is the CIS2051, we don't know when or if the global shutter will be enabled. But it would be nice.

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                      • #12
                        Originally posted by Tzedekh View Post
                        It's been rumored that the BMC's sensor is the BAE/Fairchild CIS2051, which has a global-shutter mode. As present, the BMC's sensor has a rolling shutter, and even if it is the CIS2051, we don't know when or if the global shutter will be enabled. But it would be nice.
                        If I'm not mistaken, that chip loses 2 stops of DR when in global shutter mode. It would be cool if it were possible to switch shutter modes. You could leave it in rolling-shutter mode most of the time for the DR, and switch it over to global-shutter mode when you need moving objects to be rendered correctly.

                        On the other hand, VFX heavy films are shot on Red and Alexa all the time, and those cameras have a rolling shutter. Perhaps it's not always a big deal in practice?
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                        • #13
                          Originally posted by Wesley Byram View Post
                          If I'm not mistaken, that chip loses 2 stops of DR when in global shutter mode.
                          I had not heard that. Do you have a link to that information? I was aware that in global-shutter mode, the maximum frame rate was cut in half.

                          On the other hand, VFX heavy films are shot on Red and Alexa all the time, and those cameras have a rolling shutter. Perhaps it's not always a big deal in practice?
                          True, but I still occasionally read about how tracking in VFX shots is made harder because of rolling shutter. And we don't know how the BMC's sensor stacks up against the Epic's and the Alexa's with respect to rolling-shutter wobble. Because the CIS2051 has a global-shutter mode, Fairchild may not have done much to minimize artifacts in rolling-shutter mode. If the BMC does use that sensor, wobble may be more pronounced than in the better-optimized Epic and Alexa sensors.

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                          • #14
                            Originally posted by Tzedekh View Post
                            I had not heard that. Do you have a link to that information? I was aware that in global-shutter mode, the maximum frame rate was cut in half.
                            http://www.fairchildimaging.com/down...Whitepaper.pdf

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                            • #15
                              Originally posted by Tzedekh View Post
                              I had not heard that. Do you have a link to that information? I was aware that in global-shutter mode, the maximum frame rate was cut in half.
                              I tried to find where I read that, and all I could come up with was a post in the original epicly long dvxuser thread: http://www.dvxuser.com/V6/showthread...-for-3k/page54

                              Edit: According to the white paper Macalincag linked to, it appears the global-shutter mode does increase the noise in the image, which would lower the usable DR.

                              At any rate, we'll just have to wait for some controlled tests to see how fast or slow the sensor readout is. If it's as bad as the 5D MKII, for example, that could be a deal breaker for me. If it's more like the C300 or AF100, then that's probably good enough for tracking, as long as the amount of movement in the scene is small. We'll see.
                              Last edited by Wesley Byram; 06-06-2012, 09:50 AM.
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