"With its quieter and faster operation and, especially, its markedly superior performance at 50mm f/2.8 (the setting you will most often use for portrait shots) the Sigma is the one I prefer. It is also a much (much!) better choice for video. Unfortunately on my camera its AF proved somewhat unreliable at wide angle – even when using live view."
Any thoughts? I use a Canon 60d, and I only have a 18-200mm F/3.5 lens.
Link to Comparison: http://francoismalan.com/2012/04/fast-sigma-vs-tamron-stabilised-17-50/
Help is appreciated.