In 1954, Leica Camera (www.leica-camera.com) launched its M-series of rangefinder cameras, which photojournalist Henri Cartier-Bresson (1908–2004) and other devotees have called the purest photographic instruments available. Last month, the German company introduced the Leica M8, the line’s first digital device. The $5,300 M8 retains all the attractions of the analog M-series, including its speed, precision, and quiet operation. One can only imagine the acts of living that Cartier-Bresson would have captured with this latest Leica. . . .