I'm going to choice wide lens for landscape. Please give me idea about Sigma Zoom Super Wide Angle 10-20mm f/4-5.6 EX DC HSM Autofocus Lens for Canon Digital SLR Cameras, and Tamron Zoom Super Wide Angle SP AF 17-35mm f/2.8-4 Di LD Aspherical IF Autofocus Lens for Canon EOS. Of course, 10mm is better than 17 about wide. But Tamron said your lens have 104 to 63 Degrees than 102.4 - 63.8° of Sigma. Is that true? I really confused about that things? Which is better?


