This calculator is in no way related to the Blackmagic Design company or the Metabones company. It was made purely as a practical tool (and extension to my website) to discover which lenses are giving you a certain Field of View (FoV) on the new Blackmagic Design Pocket Cinema Camera (BMPCC).
The calculations are made based on the sensor-size data as mentioned on the Blackmagic Design website, which comes down to a crop factor of 2.88x compared to the fullframe (35mm) equivalent. The Metabones Speedbooster for Micro Four Thirds will have a multiplier of 0.71x - this is taken into account when activating the Speedbooster option.
This tool was provided as a courtesy to all whom might benefit from the (indicative) results. I know for a fact that it was useful to me on making the first shortlist of lenses for when the BMPCC arrives.
Questions and/or suggestions can be send to email@example.com.