Sigma 50-100mm F1.8 Art DC HSM Lens for Canon Covering three very popular short tele focal lengths when crop factor is considered 85mm, 105mm, and 135mm this lens equates to a 75-150mm constant F1.8 aperture zoom. As an Art lens, the sharpness, even wide open, will rival primes while offering . expected to be widely popular with both still photographers and videographers