The eldest son of the "wool comber, master mechanic and merchant" Georg Rodenstock (1819-1894), he was 14 years old when he started selling haberdashery, without trader's or travel's licence, to support his family.

He learned soon how to refill damaged tubes of mercury barometers, which he bought from another haberdasher and sold "with some advantage" on his sale trips.

Josef Rodenstock had already developed the so-called "diaphragm lenses" in the years before settling and started now to sell them and to extend on his ideas.

According to adverts in the "Fliegende Blätter", Rodenstock already had more than 17 sales outlets in German Empire, Switzerland, Luxembourg and Bohemia.

The company was as optometrist the imperial warrant of appointment of the German Emperor and King of Prussia Wilhelm II.