Checking the flange focal distance with FDC provides an exact indication of the amount and direction (+ and -) of the deviation between the actual flange focal distance and the ideal flange focal distance. This allows you to determine the combination of necessary adjustment foils (shims) to correct the flange focal distance. The formerly slow and tedious approach to the flange focal distance is no longer necessary.
For stationary use, e.g. in a studio, the FDC can be powered by a mains adapter (AC/DC: in: 100-240V; 50-80 Hz; 300 mA// out: 5V; 1.5 A) Another possibility is, using the unit with a DC 3V battery which makes the FDC-multi very attractive for an easy handling on set, bringing laboratory accuracy to the field.
When the FDC is mounted on your camera you can start the measuring procedure. The flange depth of PL mounts can be measured directly. On top of that shorter flange focal distances, like EF-, MFT-, E-und F-Mount-cameras, can be measured with the same accuracy as well by adding the respective adapter (only possible with the FDC multi). The FDC provides a highly accurate connection which does not alter the measurement accuracy.
Evaluating the flange focal depth is based on projecting a red bar and a pair of green bars from different optical axis onto the chip. In the right distance from the projective system the red bar comes to lie right between the green bars forming a symmetrical image that can be easily recognized looking at a monitor that is connected to the video output of the camera.