https://www.artcore.tj/e-blog/%d0%bf%d0%be%d0%b4%d1%81%d1%82%d1%80%d0%be%d0%b9%d0%ba%d0%b0-%d0%b0%d0%b2%d1%82%d0%be%d1%84%d0%be%d0%ba%d1%83%d1%81%d0%b0-%d0%bd%d0%b0-sigma-501-4/
Подстройка автофокуса на Sigma 50/1.4