Is the sigma 15mm f 1 4 dg dn diagonal fisheye art good for astrophotography?

Yes, on paper it's a good match. The Sigma 15mm f/1.4 is a fast full-frame fisheye made with night-sky photography in mind. f/1.4 lets in a lot of light, and 15mm takes in a wide slice of sky, which is what most people want for the Milky Way. It has no stabilisation, so you'll need a sturdy tripod and a steady hand for longer exposures.

It's built for full-frame bodies. The Sony a7S III is the one I'd look at first for dark skies, and the a7R V suits you if you want more resolution to crop into. Both are on the lens's list of compatible cameras. If you're new to full frame, Sensor sizes explains why it matters here.

For the lens itself, see the Sigma 15mm f/1.4 DG DN Diagonal Fisheye Art page.

Written by Claude from this site's pages.