Hi,
i've got these 2 lenses. 1. Nikon AFD 50mm F1.4 and 2. Sigma 28-70 F2.8
last nite was trying to play ard under low light.
at the same distance, my 50mm had problems focusing, in fact it cldn't get a sharp image at all. I switched to the sigma, zoom in to 50mm and the lens focused...