So I purchased one of the new Sigma 18-300mm F3.5-6.3 DC MACRO OS HSM Contemporary lenses for my Canon T1i and the USB dock to make adjustments/updates. There is some definite back focusing at middle ...

Sigma’s venture into lenses made solely for mirrorless fans just took a leap forward with the brand’s first full-frame, telephoto zoom for L-mount and E-mount cameras in Sigma’s Contemporary line.