Launched alongside Canon's new EOS-1D Mark III digital SLR today was the EF 16-35mm f/2.8L II USM lens and speedlite 580EX II flash. The new L-series wide-angle zoom lens has improved peripheral image quality and is compatible with all EOS SLRs. It contains three high-quality aspherical lens elements and two Ultra Low Dispersion (UD) elements to keep lateral chromatic aberration to a minimum. This helps to insure that each photo has the best resolution, image quality, and contrast possible. The newSpeedlite 580EX II Flash replaces the popular Speedlite 580EX Flash, and incorporates several important improvements, including "a metal hot shoe with an improved locking mechanism for added durability, an external metering sensor for non-TTL automatic flash exposure control and a PC socket for use with non-dedicated slave triggers."