Camera data of Galaxy S3 for tracking
According to this thread on Blenderartists, sensor size is 4.54 × 3.42 mm and focal length is 3.7mm, which gives a crop factor of 7.7 and a 35mm-equiv. focal length of 28.5 mm.

Be careful to check if the video is cropped in comparison to the still images, reducing the effective sensor size.