Miedema's father was a sculptor, his grandfather and uncle were painters, and he, too, studied fine arts in Rotterdam, followed by an apprenticeship with a photographer, because that's what he wanted to be. In 1910, he opened his own photographic studio in Rotterdam.
His family and friends always told him that he had a nice voice, so he took singing lessons. In 1916, he made his debut in concert, and in 1917 in opera. He was successful enough to close his studio, and focus on a tenor career in the Netherlands. He moved to London in 1921 and appeared in films, and then became the private tenor of a wealthy family of margarine producers; he lived at the mansion of Sir Henry van den Bergh, and his work was to give house concerts. In 1922, Sir Henry rented the Wigmore Hall, so as to make his private tenor known to the public. That really started Miedema's career. He appeared as Pinkerton with the Carl Rosa Company, moved back to the Netherlands the same year and joined the Dutch National Opera in Amsterdam (a short-lived enterprise). Next, he had a contract in Ustí nad Labem, then in Braunschweig, eventually in Mönchengladbach, where he had no success, so he returned to the Netherlands. He gave recitals, he sang on the early radio, and he was part of two mixed quartets, the Haagsche Vocaal Kwartet and the Van Zanten Kwartet. In 1930, he was hired by the Vlaamse Opera in Antwerp; a year later, after a performance as Lohengrin, he suffered a serious heart attack, whereupon he gave up his stage career, although he went on with quartet performances for a while. From 1934, he taught voice at the Rotterdam conservatory.
In 1938, he returned to photography, and opened a studio in Utrecht, which he ran into the 1960s; he specialized in portrait photos. After that, he toured the Netherlands with elaborate public slide shows. He had always painted, just for fun; in his eighties, he made painting and sculpting his new (and last) vocation.
Reference 1; reference 2: Youtube