Jacob Riis, a writer and photographer who exposed poverty in late 19th century New York City, used crude tools ... He acquired his flash lamps on eBay. He says they give off a huge flash ...

Danish photographer Jacob Riis captured ... in darkness using a magnesium powder to produce a flash. His work led to changes in the city and prompted then-Police Commissioner Theodore Roosevelt ...

Flash photography can be a mystery ... and shows star trails and city lights on Earth some 250 miles below.

There are few things that announce a photographer’s presence more than a camera’s flash does. That blinding flare of pure white light has been photographers’ beacon since its introduction to ...