Having the right distance between the camera and the FoCal Calibration Target is important in getting accurate and useful calibration results. FoCal’s interactive Target Distance Tool lets you check the required distance for calibration quickly and easily.
Choose Help > Target Distance Tool from the main FoCal menu to open the Target Distance Tool.
The Target Distance Tool has 2 panels.
Target Distance for …
With a camera connected (as shown in the image above), the Target Distance for… panel will display the appropriate distance for testing with the attached lens. If there is a zoom lens attached to the camera, you will see the distance for both the Wide and Telephoto ends of the range.
Explore Target Distance
With or without a camera connected, you will see the Explore Target Distance panel.
You can choose any focal length using the slider, moving this slider will update the minimum target distance displayed at the bottom of the window. In the example above, for a focal length of 24mm, we require a minimum target distance of 1.2m.
Note that the crop factor of the camera is not relevant in determining the target distance requirement for calibration, so the distance is the same whether you are calibrating a full-frame or cropped sensor camera.