Sam Chang was a Hawaiian luthier/producer working from the 1920's through to the 1940's. He started out working for Kamaka in 1916, but having learned the art he started making his own as well, eventually leaving Kamaka and setting up full time on his own. 

He liked the Aloha and Hawaiian crest idea, (like the Aloha Mfg.Co.) too, and used his own version on a lot of his Ukuleles, (often with a white background), though he sometimes put his name on the back. He generally made Ukuleles for other people to sell, most of his output was sold by the Summers Brothers at their hotel concessions, however he did make Ukuleles to sell with other retailers, like Bergstrom, too. 

He is one of the few pre WWII Hawaiian makers who did make the larger scales of Ukulele as a 4 string Ukulele rather than a Taropatch or Rajao.