Open the lens to the widest possible aperture to achieve the smallest depth of field. If the location is correct, the rectangle will resemble a square in the lens.
You can set everything at the distance from which you usually photograph the most or take advantage of the online hints from the LensAlign distance tool. The center of the lens outlet and the rectangle-center of the pyramid should be positioned opposite each other at the identical level at a distance of about 6 feet or the suggested focal length of the manufacturer’s specification. The location of the system must be strictly horizontal and stationary, which is the primary condition for successful lens calibration. Place the camera on a tripod or a flat, stable surface, such as a table, and put the focus pyramid opposite on a flat surface. Installation should be carried out in a space that offers plenty of ambient light.
But with the focus pyramid as a tool proven for years, it is common for fairly accurate and inexpensive manual autofocus calibration. This method works using a regular ruler and even a printed sheet with divisions.
