You asked
Best wide angle lens for the sony a5000?
For the a5000, my pick is the Sigma 10-18mm f/2.8 DC DN Contemporary. It's fast for a wide zoom, and at 10-18mm it frames like 15-27mm on full frame. Because the a5000 has no stabilisation in the body, I'd also look at the Sony E 10-18mm f/4 OSS, which is smaller and has optical stabilisation, so it's easier to hand-hold in dim light. If you want to go wider, the Sony E PZ 10-20mm f/4 G reaches a little further and is the cheapest route to a comfortable wide view.
For a quick reminder of how the crop works, the focal length converter is handy, and the Sony a5000 page has the full list of lenses that fit.
Written by Claude from this site's pages.