Oscar G. Mason (1830 – March 16, 1921), better known as O. G. Mason, was an American photographer and radiographer. For most of his professional life, O. G. Mason directed the photographic department of Bellevue Hospital in New York City. He retired from this position in 1906.
Very little information exists of Mason’s activities as a daguerreotypist before he was engaged by Bellevue. Records show that he worked for the Meade brothers as chief camera operator at their 233 Broadway, New York, gallery soon after it opened in 1850. There is also evidence that Mason spent a few years in Northfield, Vermont and Springfield, Massachusetts, before returning to New York sometime in the middle 1860s. It is not clear, however, whether he actually resided in these cities or was simply registered as a freelance photographer and entrepreneur, promoting the services and products from his commercial enterprise, O. G. Mason & Company. According to his obituary in the New York Times, O. G. Mason’s affiliation with Bellevue began in 1856. There is very little evidence to support this date, but in a report written for the year 1881, Mason comments on twenty years of research in photomicrography. More than likely this would have included work for the department of microscopy established at Bellevue in 1862. For many years Mason was an officer of the American Microscopical Society of New York.