camera obscura noun a darkened box with a aperture for projecting the image of an external object onto a screen inside. It is important historically in the development of photography. Pinhole photography is from time to time a trend in artistic photography. Use with a digital SLR allows metering and composition by trial and error, and is effectively free, so is a popular way to try pinhole photography. And so I did, documenting Philadelphia subway commuters. They are grandmothers, couples in love, acquaintances, and 'average people' simply on their way. People riding the subway look...