John Baer grabbed a Leica from a captured German soldier in 1945. Nearly 50 years later, his son found the negatives – which were some of the best postwar street photographs ever

A woman rests her head on a man's shoulder on a Washington Square Park bench, eyes closed, while he gazes away into the middle distance with a book in his lap.

The story of how John Baer came to be a photographer is one of the most intriguing origin stories in the discipline. In 1945, serving with the 644th Tank Destroyer Battalion, he acquired a Leica from a captured German soldier. Then he pointed it at his war-weary comrades and started making pictures.

That's it. No formal study or training, no darkroom apprenticeship, no photographic theory. Just a man, a commandeered camera and an instinct that turned out to be quite extraordinary.