I took this lens after I tried staffers from tamron and sigma. This one is better! The quality is really comparable to the El class. heavy is a plus. It sucks dust, yes . the only joint. For such an amount, they could have done dust and moisture protection, but I’m very pleased with it, I use it in most cases, at 55 mm f2.8 a tolerable portrait can be played. This lens is really good, and it’s better not to find a crop . except that the new sigma 18-35 f1.8 can do it, but I haven’t held it in my hands yet. Photos from him paired with 7d http://fotki. . Ru/users/max-abdrazakoff/album/432373/