After attending school in Bremen, Ruetz studied sinology, with Japanology and journalism as secondary subjects, at the University of Freiburg, in Munich and Berlin.

[1] Ruetz was a member of the German Society for Photography (DGPh), the Gesellschaft Deutscher Lichtbildner (GDL)/Deutsche Foto Akademie and the Academy of Arts, Berlin.

[3][8] His portraits of the Außerparlamentarische Opposition (APO), now part of German photographic history, were immediately bought by major newspapers and magazines in Germany and abroad, including Time, Life, Der Spiegel and Stern.

[1][3][9] In 1968, Ruetz covered the invasion of Czechoslovakia by Soviet troops (Prague Spring) and reported for Stern on the military dictatorship in Greece, as on the World Festival of Youth and Students 1973 and the International Workers' Day 1974 in East Berlin.

He later accompanied François Mitterrand on his election campaign, visited Chile after the victory of Salvador Allende[10] and reported on the war in Guinea-Bissau and on many other international events.

In contrast to the individual picture pairs of the Second Sight project, Timescape comprises photographic sequences made over many years.

The photographs give a clear indication of how much people, places, squares, apartments, and nature are in a state of change.