Camera Match
This tool matches the camera to an image with two vanishing points. The vanishing points are created using two line bundles which represent the planar axis in the image. It is important that the image is not cropped so it needs the original aspect ratio from the camera. Otherwise it is not possible to match the correct focal length of the lens and the orientation of the camera. The mathematically bases is the paper Using Vanishing Points for Camera Calibration.
You can also watch the tutorial video
First load the image with "Load Image". This will create a backdrop item with the image, sets the active 3D viewport to front and creates a new mesh layer. The mesh layer is for the x and y axis lines.
Next step is to draw two pairs of lines with the curve tool. The first pair will be the X axis and the second the Y axis.
It is assumed that the the X and Y axis are perpendicular to each other. If this is not the case the camera will not solve correctly.
With the two line bundles created switch to edge mode and select the two lines for the first vanishing point and press "Set First Vanishing Point".
Do the same for the second vanishing point. Now you are ready to create the camera.
Press "Create Matched Camera" and the camera will be created in the scene origin and the approximated orientation of the two vanishing points. The 3D view is set to the new camera, the backdrop is set to "Camera" and the render resolution is set to the resolution of the loaded image. If you like to lock the orientation of the camera to not accidentally change it activate the option (on via default). The rotation channels are locked via a group.