PhotoModeler requires a description of the camera used to take the photographs. This description needs to be created only once and is used for every subsequent project done with this camera.
Each different camera or each lens/camera combination needs its own description. This description includes data on the focal length, imaging scale, image center and lens distortion. PhotoModeler uses this information to build a proper geometrical relationship between points on the photograph and points in 3D space. The camera description file describes the camera, the lens and the scanner as a set. If any of these change, a new calibration is required.
The camera descriptions can be approximate or fully calibrated. Creating an Approximate Camera requires entering in information about the camera and creating a camera file. Creating a calibrated camera involves taking photos of a calibration pattern (supplied with the package) and running the Camera Calibration.
When you want to start quickly with a new camera the best way is to create an Approximate Camera first, use it in PhotoModeler and then at a later date when higher accuracy is required, create a calibrated version of the camera description. See the section Working with Cameras for additional background.
In addition, there is the Automated Calibration option that performs camera calibration at the same time as solving the project (Automated Target and Automated SmartMatch projects).