You asked
Best wide angle lens for the sigma bf?
If you want one wide angle lens for the Sigma BF, I'd pick the Sigma 14-24mm f/2.8 DG DN Art. The zoom covers ultra-wide to wide, and its constant f/2.8 keeps the exposure steady across the range. That matters more than people expect, as the lenses guide explains.
If you want a fast prime, the Sigma 14mm f/1.4 DG Art gives you the widest aperture on the list, which helps in dim interiors and for night shots, though you give up the zoom.
For a cheaper option with macro, try the Panasonic Lumix S 14-28mm f/4-5.6 Macro. Its slower aperture means less light, and it gets darker as you zoom in.
Written by Claude from this site's pages.