The interface is made up of 3 main windows:

This displays the view from the main camera and allows the user to accurately work with the calibration chart

It contains the following options:

A tabbed window allowing the user to choose between the settings tab and a view of the lens curve.

Profiler contains the following options:

The 3D view has a dropdown to change the currently viewed parameter, additionally the following controls are used in the 3D view:

Two green lines are shown on the 3D view, these represent the positions of the zoom and focus encoders.

The calculated lens information, either from a specific calibration point, or inferred values when the lens is in-between two calibration points

Along the lower edge of the panel are six buttons, they have the following functions:

There are a number of different charts that can be used for calibration

The lens profiling setup has been designed to be as flexible as possible, there are some steps that while not required will make the process easier though,

We refer to the first calibration point as the "golden point". This point could be anywhere on the lens' focus (or zoom if applicable) but we typically advise it to be at the widest focal length available and either at close focus or infinity depending on where the calibration chart is easiest to detect

Make sure the correct chart is chosen

Press start - from this point on do not change the zoom or focus of the lens at all until the point is calibrated. Iris can be adjusted if desired to help focus/expose the calibration chart

Display the calibration chart to the main camera, a coloured overlay will be rendered over the chart when it is successfully detected, press F12 or "Use image" to take a picture of the chart. An additional overlay in green will be displayed showing where the chart was in the frame. Continue taking images until every part of the frame has been covered by the chart

Press "Calibrate" to create the calibration point. This will calculate the FOV and distortion for this exact part of the lens, a point will be displayed in the 3D Graph.

At this point you can continue to create additional points, however it is recommended to actually leave the lens calibration window and to check the quality of the calibrated point before proceeding further, the section below describes how to do this

Close the lens calibration window, make sure the lens is still at the same focus/zoom point that was calibrated.

Conduct the camera bar to main calibration to work out the alignment between the main camera and camera bar, the Liveupdate method is typically the easiest method for this and is described in Witness to Main

Use the image modelling tab to place the zero point, ideally choose a point as far away as possible (this helps minimise any errors from alignment)

Switch to the augmented reality view where the Ncam cube should be displayed over the zero point, pan the camera so that the cube move from the centre of the frame to the edges. If the point is well calibrated then it should stay fixed to this point across the pan.

If the cube begins to drift as it approaches the edges of the frame then the calibration point will need adjusting, this is described in the next section

Return to the Lens profiling window, in the camera view select Ncam cube overlay, this will display a representation of the Ncam cube in the same position that it was viewed at in the previous step.

Pan the camera so that the origin point of the cube is near the edge of the frame, make a small adjustment to the H focal value (select the point in the 3D view first), scrolling the mouse wheel while the value is selected is typically the easiest method to make an adjustment.

Continue adjusting until the corner of the cube is back in the same position it was when in the center of the frame

Center shift is an important concept to understand and account for when dealing with lens calibration. It is when the optical center of the image changes as the lens zooms in and out. If it is not accounted for when calibrating it can cause CG elements to drift when zooming.

Some lenses will exhibit center shift far more than others. To see how much center shift is present, zoom the lens in all the way to a fixed feature in the environment, line the center mark of the camera up with this feature and then, without adjusting the pan or tilt at all, zoom out. the amount that this feature drifts from the center mark is the result of center shift

Once the initial (golden) point is completed and has been checked to make sure it is accurate, repeat the process for the rest of the lens.

The number of calibration points required depends on the type of lens, a prime lens will typically only need 2, one at minimum and one at maximum. While a zoom may require upwards of 30

When creating new calibration points, always try and keep them in organized row's and columns, creating new points at random points on the lens will make it harder to achieve an accurate calibration

While creating new points, remember to constantly return back to the golden point while looking at the Ncam Cube overlay to ensure that the calibration is working well

When using the calibration charts there are a few factors to bear in mind

Some charts require the whole pattern to be seen at once, the A3-1 chart for instance. If you are having trouble getting the camera to detect the pattern, make sure nothing is occluding the chart pattern, shadows or uneven lighting can cause this issue too

Being heavily out of focus can make certain patterns harder to detect, 70mm mosaic for example. Sometimes Adjusting the Iris of the lens to increase the depth of field can make it easier

Tilting the calibration chart will typically provide a better calibration result as demonstrated in the pictures below