Ultra-wide angle field of view Constant f/3.5 aperture Robust EX build quality The Sigma 10-20mm f/3.5 EX DC HSM is a versatile wide angle lens offering a fixed aperture, making it perfect for an EOS 40D or similar shooting landscape or architecture images. Designed for the advancing amateur this lens offers a very high level of specification, especially as Canon’s closest equivalent is a 10-22mm EF-S lens, is only a variable aperture. With a 102.4 degree perspective the Sigma 10-20mm f/3.5 EX DC HSM can fit in even the most wide-spanning groups or cliff top views. The EX build is robust enough to put up with an energetic day’s photography, while being light and compact enough not to be a burden when attached to the camera body.