- Place your calibration bar at the center of your rig. The closer you can get your markers to the edge of the frame, the better you're quality is going to be.
Do a first manual alignment of the cameras. The more precise you can be, the less crop you're going to have on your calibrated images. Aim the cameras at the center of the calibration stick as show on the figure below. We recommend using the liveview on the back of the camera to fine tune the position of the cameras and adjust the focus. You can use grid display to help. We also recommend using the 10x digital zoom to fine tune the lens focus.
- Open Xangle Camera Server, go in the Calibration panel.
- Make sure that your camera settings are good enough to have contrasts between your markers and the background
- Click on the "Trigger" button. This is going to take one picture with each camera. From there, you can have a look at the status down the page. Adjust the camera settings if needed, then take another shot. If the markers are well defined, then you can start playing with the calibration zones and marker colors
- Calibration zones: place the two calibration zones to wrap up as close as possible the two markers. The idea here is to avoid picking up anything that would look similar to the markers. In my example below, if I go outside of the black t-shift, then I get problems with some pixels that are too similar to the marker
- Calibration settings: use this panel to do a pick-color on each of the two markers. Click in the preview image to pick the right color of the marker (top, then bottom)
- Click on "Recalibrate" to perform a new calibration based on the same image set.
- Having a black area around your markers is the best way to ensure easy calibration. This is THE key element for an easy and successful calibration when working with 18 cameras or less
I describe this part clearly on this post: https://xanglecs.com/blog/diy-bullet-time-calibration-panel-close-up
- In a full 360 environment, you can use a regular calibration stick and move around it in interval mode (thanks for the tip, Spliceboys!). Demo here: https://www.instagram.com/p/ByKPUqSH6Jm/
- Calibration is usually better when shooting in large JPEG. Once it's done, you can go down to a smaller resolution and it is still going to calibrate properly
When having extreme inconsistencies in the camera status, check out the following items:
- Zoom lenses: make sure that the focal length is at the same position for all cameras lenses
- Make sure that each camera is in focus (and if you change the focus, you need to calibrate again as it slightly changes the focal point)
- (Canon) Check if the zoom box gets out of the center of the image (in live view). Press the delete button (garbage icon) to bring it back to the center.
- Make sure that the markers are inside the bounding box (purple) for each frame
The calibration bar
- You can get our fancy calibration bar from our online shop. This is by far the best option IF you're shooting in full 360. The added value of this one is that the markers are back lit (easier to detect), and it comes with a standard tripod mount. Two versions are available. One for close-ups (great when your center point is close to your cameras), and a taller one with larger markers (that's the one we're using with our cameras 11' away from the center, at 18mm).
- If you have a very small rig (12 cameras or less), then just go with a black fabric or black panel with two square colored markers on it. The center marker is ONLY used for you to aim the camera at the center. It is not used in our software. It has to be a different color than the two other markers
- In a full 360-degree environment where you can't control the ambient light, you can go in interval mode and move around your calibration bar using a black drape (thanks SpliceBoys for the trick!). Check out these two sweet demos: https://www.instagram.com/p/ByLY7e5hRpE/ and https://www.instagram.com/p/B25bZOLAClW/
You can also calibrate manually the markers. This solution is rarely needed, but if for some reason you can't calibrate automatically, then use this tutorial: https://xangle.zendesk.com/hc/en-us/articles/360037621871