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Go Back to Page 1 Post Production of the RAW Files
Some might start explaining a camera with the actual camera. I think with the Phantom workflow, it might be best to start with talking about the post production delivery and meeting post expectations.
This is where we have had the biggest problems and definitely needs the highest regards in terms communications between the camera rental house and the postproduction facility. The digital file that is streamed out of the camera and onto a hard drive is a proprietary RAW format. A RAW image file contains minimally processed data from the image sensor of a digital camera. RAW files are so named because they are not yet processed nor do they contain a wrapper that can be used with a video editor or even viewed. A RAW file must be processed by a raw converter in a wide-gamut internal color space where precise adjustments can be made before conversion to a file format such as MOV or AVI for editing, or further postproduction manipulation. These images are often described as "RAW image files" (note capitalization) based on the erroneous belief that they represent a single file format, and thus deserve a common filename extension, .RAW. In fact there are dozens of raw image formats in use by different models and manufactures of digital cameras. If you want the greatest range available in terms of color space, resolution and image detail in your highlights and your shadows, working with the RAW file offers you the greatest tool set.
Vision Research was way out front of the post production industry and it is taking quite a lot of learning curve for us to develop the skill sets and tools to pull all this information out of the RAW files and onto a video format.
As a camera rental house we developed a couple of different RAW file conversion processes in support of our clients and in the interest of delivering the superior quality image that this camera is capable to produce. I spend a lot of time on the phone with the post houses, however that time is, and has been, extremely invaluable for my foundation and utilization with this camera and other RAW format cameras like the RED and the Arri Alexa.
For a quick, on-set, basic level, we have developed a “Lunchbox” solution. The Lunchbox is an extremely efficient Windows based PC built into a single lightweight package. The software at the core of this package is a program from Iridas called Framecycler. Framecycler reads the Phantom RAW file in real-time. In addition to offering a color and gamma correction tool set, Framecycler can export the results to a variety of video formats and image sequences. This enables us to deliver to the post house any number of files to match into their specific workflow. You can download a trail version of Famecycler off of their website.
To meet the demands of a large production, we manufactured an Apple based package that includes data verification, color correction, and software that can transcode the RAW file into any number of editorial demands as well as iPad dailies.
Operator Specific and What Stuff To Look Out For
I stated earlier that this camera was extremely easy to use, and I stand by that. However, this is not a "point and shoot" prosumer camera, and there are issues to watch for. When any camera has a lot it can do, that means there are a lot of settings you can do wrong. As we get deeper into the camera's control software, Vision has absolutley fantastic support built into the software that you can find under "Help" in the program command line. This has raised my IQ at least 10 points when under fire by on set pressures. The software is available for free to download off their website and it can run without a camera attached. Get it and play with it before you come play with the camera.
Current Session Reference and Black Balance
Black Balance within the Phantom system of cameras is always the same. With the Flex, IF you are using it HQ mode, the camera is adjusting the blacks almost all the time so it is somewhat considered "automatic." With the HD Gold or the Flex shooting in "Standard" mode, then you must accomplish this manually.
Pixels are just little light meters, OK maybe a little more, but basically they get more and more excited the more light that hits them. A chip set is a whole bunch of crowded individual pixels. In order to get every one of those little guys measuring the same quantity of light exactly the same, we have to tell them what zero is and what 100 is. Our measurement demands are so exact, since we are working with millions of possible colors and brightness levels, and since the atmosphere in terms of heat, cold, humidity and other influences can change how a pixel will react, we have to "teach" those pixels every time something changes. Every time we change the capture speed, the shutter speed or the resolution, we need to give the pixels a "Reference." Since this is a single chip camera, the camera is also doing a magical "Bayer Pattern" scheme that changes as the resolution and capture speeds change. The camera software offers two routines to accomplish this.
There are three ways to "Black" this camera. Each of the three have a right time and place. There is "Black Reference," "Current Session Reference," and then "Black Balance." I admit to this being a little confusing, but this is absolutely critical to ensuring a usable file and not a very expensive postproduction nightmare.
If you are downloading to a hard drive from the camera RAM memory, not using a CineMag and not recording from the video playback through the camera, the Black method to use is "Current Session Reference." This runs a program through the camera to get every pixel that you want to use on the same measurement set and assign the perfect logarithmic schemes to the Bayer pattern. This is exactly as complicated as it sounds and is the reason to pay a lot of attention to Session Reference. A text window will come up and ask if you want the results to write to the "Camera Non Volatile Memory." Answer ‘yes’ to save the settings to camera NV Memory in order for the CSR to affect the video output and CineMag recording.
‘Black Balance’ is accessible only through with the on camera controls. You will need to have camera's "On Screen Display" enabled in the software to see this function through the viewfinder. Locate the scroll knob on the operators’ side of the camera, as you rotate this scroll, the active function in the viewfinder will change colors. When you scroll to "Black Balance," push in and twist to "OK," then let go and watch the camera countdown from 8 to 0. When recording to a CineMag, or using a video workflow, this is the recommended method of black referencing. The BB is much faster and affects the HDSDI output and the CineMag recording. However, the BB is stored separately within the camera memory and can be overridden by the CSR in the software while saving raw files from Camera RAM. It is therefore best to stick with one method of Black Balancing and to apply it consistently throughout the shoot. If you need to switch from using the on camera controls to using the software controls, you must power down and restart the camera for the software to properly apply the black reference information.
The Current Session Reference or Black Balance should be done at the Image Resolution, Frame rate and Exposure time that you are planning to record, and is best done directly before the images are captured. If you have used the Black Balance on the side of the camera, the camera must be re-started before a CSR will affect cine images saved to the CineMag. For this reason, we recommend using the onboard controls when recording to a CineMag.
"Black Reference" is accessible through the Phantom Software under / Acquisition / Setup and Recording / Options / Black Reference. This references the entire sensor, forces your acquisition parameters to change, and overwrites the factory references that are unique settings to one particular serial numbered camera. This is NOT a good option for most shooting conditions and Vision tells us to minimize using with this.
With all three actions, through the HD out and within a window viewer on the program you will see the camera "stripping" through the image as the black values are cleaned up. The result will be a visually solid black image. If it is not done correctly, you will see a color tint to the blacks (make sure it is not the monitor) or you will see vertical rows of pixels that are not the same exact black as the others. If you are looking at white it normally shows as warm vertical rows, in blacks it is subtle as blue vertical rows. On thing I always try to check is to look at the monitor "Blue Only." The blue layer seems to be the most sensitive to errors and with red and green removed it can be a bit more obvious. On a waveform monitor, you should see each color channel as a straight line at or very close to 0 IRE. If any channel is raised, or when it starts arching and looks uneven, it’s time for a black balance. When doing CSR’s from the software, adding gamma in the “Image Processing” dialog will make any problem more obvious, just remember to set the slider back to your correct capture gamma.
Click on the image to see a full frame Tiff.
This black shifting has been the most problematic operation of this camera. Everyone should be on the look out because it can be difficult to see and it is not correctable in post. Each of the cameras operations, even when you are going between play and record or dumping the memory, you will see a flash in the viewers. That reset, is when a change is likely to occur and at each step the operator should stare it down and look for this vertical stripping or cross patterns in the blacks.
Lamp Flicker
I have been shooting and working as a Lighting Director for 25 Years. PhotoSonics was a staple in tabletop photography and I have a great deal of high-speed experience. Even though this is a digital capture all the same photography rules still apply. The faster the shutter the more light you need, bellows comp for macro work, and Flicker-Free does not mean high speed. While I can give you a few things to look out for, everything seems to have an exception. You will be able to see it even in the live preview modes, but certainly in the playback mode if a flicker does exists. Watch in the shadows and in the gradations between the highlights and some distinct color within the frame.
All HMI's must be in Flicker-Free mode, however, even in Flicker-Free SOME combinations of ballast and heads will still flicker. Most do not. HMI Fresnels seem to work very well. HMI's PARS, of any size, will at times reveal a flicker that is caused by their focus of the flame between the electrodes in the filament of the globes and the parabolic nature of the reflector. MOST of the time I have trouble with PARS, however, I have had some success. I tend to advise to stay always from PARS if possible. When I have to use them, you can SLIGHTLY reduce the flicker by staying in capture speeds divisible by 60.
Quartz lights 5K and above I do not believe I have ever had a problem with them other than heat. Quartz lamps 2K and below, I have had a significant number of times where we see the pulse of hertz frequency of the AC power source. Going to DC, no problem whatsoever so far, but that is not always an option. Keeping the capture speed divisible by the pulse does not usually do much good, however once it did, go figure!
And then there is the time the Director of Photography wants the flicker. Fluorescents, even Kino-Flos, ALWAYS flicker and not always at a constant cycle. Almost every stadium I have been to, besides being barely enough light, if enough, has flicker issues even if they say they are new style electronics. However, one did not. Go figure!
The only lighting guarantee I can make is that the Sun does not flicker at any speed or shutter angle. If it ever starts, your image should be the least of your concerns.
Hot, Cold and Humid
I am based in the South. We get hot and so can the camera. Please keep the camera in shade as much as possible. It can take a great deal of heat; Texas, Louisiana and New Mexico can get to 100 quick. I try to be diligent so I protect against the elements as much as I can. We have had one heat failure. The camera capture was just fine, but the HD output had colors previously unknown to mankind. When the camera was cooled back off and could be touched again, everything was back to its fantastic image. On return to Vision for a checkup, it passed just fine. We did loose time on the set though, and the producer was real upset with the AC's. If we are working at a heat level that your experience says will likely flash the film, we are most likely at temperatures that could damage the electronics.
No issues with the cold yet. Even tough we have had cameras in Houston and Houma, Louisiana, no humidity problems to date either. Would love to hear from others in order not to have cross that threshold myself!!
I am very willing to get much more involved with the software and hardware applications with this camera, however this is where it gets real techie and I will loose everyone but the starship engineers.
