Still relatively new to the company, Maitani was asked to develop a camera that would cost just 6,000 Yen, about a third less than conventional cameras on the market at the time. Because resources were not there to train him properly, he was left completely to his own devices. He decided the new camera needed to be equipped with a high-quality lens and insisted on the costly D-Zuiko lens. To reduce additional costs, he eliminated gear wheels entirely to form “Zero gear”, opting for a plastic dial instead. In October 1959, Maitani’s first camera, the Pen, was released and became an immediate bestseller.

His next aim was to develop a camera that was easier to use. After much thought and deliberation, overcoming barriers in both technology and wisdom, he developed Pen EE, which was characterised by far fewer controls than before. After the launch of Pen EE, sales amongst female buyers jumped from 2 to 33 percent.

Two years later, the Pen F came to be. What made it so different was that it was a half-frame SLR. Changes made to the reflex mirror and the evolution of the focal plane shutter made out of titanium were cutting-edge developments at the time, allowing for 1/500 sec flash synchronization.

http://olympus-imaging.jp/pen/index.html