Hello, I'm a new to photography, and my first dslr is a canon D450 + Tamron 17-50 f/2.8 which I purchased in asia 1½ month ago. Very happy with it what brings me here, is doubt about which lenses I should upgrade, due to the fact that I would like to try something with a longer zoom. My research on some sites and forums, as well taking my budget into consideration, resolved into these possible candidates: 1) Canon EF 70-300 IS USM F/4.0-5.6 2) Sigma 70-300 APO DG Macro 3) tamron 70-300 These are whats possible to buy in local stores. which one would you pick, or if you can recommend other lenses that give better value for money, please mention that and where to purchase. I live in denmark, but purchasing online from other country its not a problem. thanks in advance.