kymarto wrote:
There is nothing wrong with 3rd party lenses. They often outperform OEM lenses at a much lower price, especially the Sigma Art series. I suggest you check sites like lenstip.com and photozone.de for objective reviews that quantify such factors as sharpness, AF speed and accuracy, various types of aberrations, vignetting, flare, etc. I would avoid sites like Ken Rockwell, who is long on emotion and short on objective measurements.