When the Nikon D3 was launched in August 2007, it had an immediate impact on the DSLR market, and not only in the professional sector. The D3 was Nikon's first DSLR with an FX (full frame) CMOS sensor, but its major selling point, in the minds of many photographers at the time, was its unparalleled image quality at high ISO settings. With the D3, photographers could shoot at ISO settings up to 6400 without a significant penalty in noise, and in a pinch, even go up to ISO 25,600 (equivalent) - unheard of at the time. This versatility, coupled with a very capable AF system and rugged, weatherproof build, did much to reverse Nikon's declining fortunes in the professional DSLR market. Professional Canon users, many of whom were disillusioned by the seemingly endless problems that plagued the flagship EOS 1D Mark III at the time, flocked to the D3 in large numbers. In the process, Nikon mounted a formidable challenge to Canon in the sports and action segment of the pro marketplace.