Ncam Reality
Appendices

Retargeting

5min

What is retargeting

In Ncam Reality the term "retargeting" refers to the process of taking lens information that was calibrated on one type of camera sensor and making it usable on a different camera sensor.

This is useful as it reduces the amount of lens calibration required when working with multiple cameras, or the same camera in different operating modes.

Why does it need doing

The camera sensor can have a huge impact on the image seen through the lens. So while we often talk about "calibrating a lens", we are actually calibrating the camera and lens together.

The magnification or "crop" factor is the most visible indication of this, but the aspect ratio of the sensor is an important factor also

How to do it

A calibration can be retargeted via the "calibration panel". You are able to either update an existing calibration to use a new sensor size, or create a brand new calibration entirely

Update existing

  • Select the calibration you with to update from the dropdown menu of the calibration panel
  • Choose the "Edit Calibration" option
  • Inside the popup window, choose the new camera/sensor that you wish the lens to work with. If the camera/sensor doesn't currently exist then add it as normal
  • The lower part of the window will display the original sensor size and the new sensor size
  • Upon closing the window, a popup will display notifying you of the sensor size change, this can either be accepted (and saved) or discarded if unintentional

Create new

  • From the calibration panel choose the "Create Calibration" option
  • In the popup, choose the camera/sensor that you wish the lens to work with. If the camera/sensor doesn't currently exist then add it as normal
  • In the lens section, from the "Use Template" section, find in the dropdown the lens that you wish to use
  • The lower part of the window will display the original sensor size and the new sensor size
  • Upon closing the window, a popup will display notifying you of the sensor size change, this can either be accepted (and saved) or discarded if unintentional

Always try and retarget from a big sensor to a small sensor

If a lens is calibrated initially on a very cropped sensor, it can cause problems when trying to retarget to a bigger sensor. This is because that certain parts of the lens just simply won't have been calibrated initially.

When using lenses on multiple different cameras we always recommended to calibrate the lens initially on the largest sensor mode, this will then give the most flexibility when retargeting in the future