Multi-Camera Matching and Creating a Streaming Picture Profile Using the Sony PMW-300K1

Picture Profile/Color Matching

Once all camera and lens pairs have been shaded, remove the white card from the frame and replace it with the chip chart. Before switching the monitor over to vectorscope mode, you will need to set proper exposure by using the 11-step grayscale. Adjust the framing of each camera to fill the frame with the chart’s grayscale, then adjust the f-stop on the camera until the top of the displayed X waveform touches the 100 IRE mark (meaning that the pure white chip on the chart is at 100 IRE). Each of the squares in the X represents a different value of gray on the chart (Figure 12, below).

Figure 12. Checking shading.

Once exposure is set, switch the monitor over to vectorscope mode. Plug the first two cameras up to the inputs to view them side by side on the scope.

Before continuing, make sure the scope is set to the proper gain setting. Every chip chart will tell the user what gain setting should be applied to the monitor for accurate color representation. The monitor’s gain setting is denoted on the scope and adjustments can normally be made via the menu.

Before color adjustments can be made, picture profiles must be applied to all cameras. Start by activating the picture profile menu on each of the PMW-300K1s. We have created a color profile called Live X that can be downloaded for free here: http://livex.tv/camera-profile/. We have also shared all of the settings we use for the profile and our reasoning for changing or keeping the variables. Load the “Live X” Picture Profile to your camera.

If you decide not to use the “Live X” Camera profile, remember the important thing is that all cameras have the same settings.

Start by looking at two of your cameras vector scopes and note where discrepancies between the placement of their 6 color points occur. The goal of this portion of matching will be to choose a control camera (the one with the best-looking scope) and match the other cameras' scopes to it.

There are 8 available adjustments within the Picture Profile Matrix sub-menu to affect how points fall on the vectorscope. The new Multi-Matrix mode can also be used for finer control over where the vector points fall. If you’re using the Live X Picture Profile, you can skip over the Matrix menu and work only on the Multi-Matrix for final adjustments, as we have already done most of the heavy lifting in the Matrix menu to get things close enough. If you’re creating your own Picture Profile, you’ll want to begin with the following Matrix adjustments before moving on to the Multi-Matrix.

1. Level: Level adjustment affects the overall saturation of the image. Increasing the level will move all points simultaneously away from the center of the scope, decreasing the level will move all points towards the center.

2. Phase: Phase adjustment will rotate all points either clockwise (if a positive value is applied) or counterclockwise (if a negative value is applied).

The final 6 adjustments are referred to as the user matrix and will affect the color matrix by adding or subtracting color values to/from each other (Figure 13, below). The available adjustments are R-G, R-B, G-R, G-B, B-R, and B-G.

Figure 13. Adjusting color parameters.

With each of these adjustments, the first color is the color that is being added or subtracted, and the second color is the one being affected. For example, the R-G adjustment will add or subtract Red from the Green channel, B-R will add or subtract Blue from the Red channel, etc.

These adjustments will most prominently shift the affected color point on the vectorscope towards or away from the color being added or subtracted. However, they will also affect the overall shape of the displayed scope. Therefore, there are no hard rules for using these adjustments, and they should be applied while viewing the live changes on the scope. Often you’ll need to go through two or three rounds of adjustments on all settings to get the scope in the best possible place (Figure 14, below).

Figure 14. The Multi-Matrix menu.

The main difference between the user matrix and multi-matrix is that user matrix adjustments will generally have an effect on the overall shape of the vectorscope being displayed, while multi-matrix allows you to isolate a specific color and affect
only that point on the vectorscope.

Figure 15 (below) shows which point will be affected by its respective Matrix Axis setting in the Multi-Matrix. Note that some of the points along the bottom of the vectorscope (yellow, green, and cyan) are affected by multiple Axis settings. Just like in the user matrix, the Saturation setting will move the selected axis point either towards or away from the center of the scope. The Hue settings works in the same way as the Phase setting in user matrix, moving the point clockwise or counterclockwise around the scope.

Figure 15. The Multi-Matrix.

Once the vectorscopes for the first two cameras are as similar as possible, you can work on the remaining cameras. Keep the control camera attached to the scope and make adjustments to the other cameras to match it. Once all cameras have had matrix adjustments applied, camera matching is complete.

Conclusion

As you can see from Figure 16 (below), we have successfully matched 3 cameras.

Figure 16. 3 Cameras matched and #2 no matching.

Here are some additional things to keep in mind:

1. When using interchangeable lenses, you need to do a new lens shade for each lens you put on the camera.
2. Camera and Picture Profile settings should not need much adjustment after the initial matching process, though it is a good idea to look at the cameras with scopes every few shows to assess matching. Every 5 shows or so should be good.
3. Because the SDI output is 422 color sampling we recommend using one of the 422 codec options for internal recording.