Barry_Green
Moderator
Inspired by lpowell's matching work in this thread, I decided to take another stab at matching the AF100 and GH2. I had previously tried and given up in frustration because of the inaccuracies of monitoring GH2 footage (its HDMI output is just plain incorrect), but a recent acquisition of some new hardware made the whole process a lot more practical. I picked up a Grass Valley ADVC-HD50, which let me take the live feed of the AF100 directly into Adobe OnLocation. OnLocation is capable of importing GH2 files (including LPowell's FlowMotion-hacked GH2 files) directly and displaying the scopes with the recorded footage, so I was able to have an accurate, recorded reference file and an accurate live image, and that made the matching process much easier.
Another reason I wanted to explore this is, while I think LPowell did a fine job, I don't necessarily shoot in the ways that his profiles would require -- specifically, his profile is based around using the 5.6k daylight preset, and I never use presets if I can avoid them. I don't find the presets terribly accurate, and even if they are accurate in terms of red/blue, there's no provision for them taking into account the green/purple shift that can happen when using various types of "daylight" lights. And I use a lot of daylight lights, I've got many different fluorescents, HMI's, and LED's, and using a preset just isn't all that practical because "daylight" lights really don't usually match each other all that well. To me, whenever possible, manual white balance is mandatory.
So my goal was to get a reasonable match in terms of gamma, color, and sharpness, using LPowell's basic GH2 setting as a starting point (meaning, I figured one of the leaders of the GH2 hack movement's settings were probably well representative of what would make for good-looking GH2 footage, and matching the AF100's noise/sharpening/coring to that baseline should prove acceptable).
What I found though, in my testing, is that the GH2's gamma curves are just so different, so boosted, there really isn't a comparable corollary between the GH2 and the AF100 with any of them, except one. One gamma curve is such a close match, that it seems obvious to me that if you want to be able to use an AF100 and a GH2 on the same shoot, there's really only one solid choice, and that's Cinema mode on the GH2, which is a very close approximation of CineLike-D on the AF100.
Here's what I did -- I used a DSC Labs VF/X chart, which has a gradient sweep from black to white, and I put the waveform monitor on single-line mode, and isolated a line within that gradient sweep. That gave me a nice smooth line from black to white. I then took a screenshot of both cameras in every gamma mode with the exposure set as identically as possible (for white clip), and then compared the results, and far and away the best match by a mile was Cinelike-D matched to GH2 Cinema.
Another reason I wanted to explore this is, while I think LPowell did a fine job, I don't necessarily shoot in the ways that his profiles would require -- specifically, his profile is based around using the 5.6k daylight preset, and I never use presets if I can avoid them. I don't find the presets terribly accurate, and even if they are accurate in terms of red/blue, there's no provision for them taking into account the green/purple shift that can happen when using various types of "daylight" lights. And I use a lot of daylight lights, I've got many different fluorescents, HMI's, and LED's, and using a preset just isn't all that practical because "daylight" lights really don't usually match each other all that well. To me, whenever possible, manual white balance is mandatory.
So my goal was to get a reasonable match in terms of gamma, color, and sharpness, using LPowell's basic GH2 setting as a starting point (meaning, I figured one of the leaders of the GH2 hack movement's settings were probably well representative of what would make for good-looking GH2 footage, and matching the AF100's noise/sharpening/coring to that baseline should prove acceptable).
What I found though, in my testing, is that the GH2's gamma curves are just so different, so boosted, there really isn't a comparable corollary between the GH2 and the AF100 with any of them, except one. One gamma curve is such a close match, that it seems obvious to me that if you want to be able to use an AF100 and a GH2 on the same shoot, there's really only one solid choice, and that's Cinema mode on the GH2, which is a very close approximation of CineLike-D on the AF100.
Here's what I did -- I used a DSC Labs VF/X chart, which has a gradient sweep from black to white, and I put the waveform monitor on single-line mode, and isolated a line within that gradient sweep. That gave me a nice smooth line from black to white. I then took a screenshot of both cameras in every gamma mode with the exposure set as identically as possible (for white clip), and then compared the results, and far and away the best match by a mile was Cinelike-D matched to GH2 Cinema.
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