Sigma 70-300mm APO DG Won't Mount!! HELP

AlexMoon · Feb 21, 2013

Hey, So i just got my new lens, Sigma 70-300mm APO DG, in the mail today. I bought it open box but the company said they tested it to make sure it works. I bought it for my Rebel t3i, which can use EF and EF-S mounts. I made sure i bought the one for Canon DSLRs. When i went to mount the lens it would slide in the hole but would only turn about 3 millimeters. I tried turning it harder, even though with my other lenses i can mount them with only the force of one finger, and still nothing. I cross referenced the mount on the sigma to the mount on my EF 50mm and my EF-S 18-55mm, and the sigma is clearly an EF mount, which is fine because so is my 50mm and that mounts with no problems. I dont see any bends or chips on the mount that would inhibit it from mounting properly. I contacted the seller and am waiting for a reply. Has anyone had this problem? Am i doing something wrong? Did i buy the wrong lens? Anything will help!

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