for the optical path was a large cogwheel which drove four smaller cogs located top left and right, and bottom left and right. Each of the four small cogs drove rack and pinions (toothed rails) attached to the lens assembly. This system functioned perfectly, and, thanks to high-quality components, also for many years of service. Only the viewfinder and back of the camera, both made of aluminium, had to be handled with care, which remained the case until the camera went into production. One more prototype was produced in 1928, and then the big moment finally arrived: on August 10, the first camera went into series production. Altogether, 14 units were made that year. Then, at 11am on Monday, 11 December, selected journalists were invited to a press conference in the festively decorated production area. Paul Franke put together press packs for the occasion, which led one magazine to publish a test report without ever actually handling the camera. Although Franke had forgotten to prepare sample photographs to distribute to the press, he neatly avoided this oversight by distributing empty, labelled cartons around the building, just for show. 1929 to 1950 New premises Demand for the new camera exceeded production capacity by a wide margin. Even though it was quite an expensive product, orders for 800 cameras were received in the first month alone. A Rolleiflex fitted with a f/4.5 lens cost , with a f/3.8 lens it cost . This success made it possible to obtain credit to buy a new factory and thrive in the midst of the Great Depression. In the old factory, a further 23,720 cameras were produced up until 1932. In 1930, the company moved into the new factory on Salzdahlumer Straße. It comprised two floors with a total area of , sufficient space to manufacture 20,000 cameras annually. Although the site was well served by public transport, it lay some distance from the city centre, so the company built a canteen and shop for its workforce, which now numbered 309 employees. Babyflex Wilhelmine Heidecke, Reinhold Heidecke's wife, suggested building a "ladies camera" – a Rolleiflex that used 35 mm film. This was the first Rolleiflex to come on the market that used a crank handle to advance the film, a popular feature that emerged on the 6×6 model shortly thereafter. The Rolleiflex 4×4 – known as the Babyflex outside of Germany – used 127