Astrophotography lens shootout: Samyang 14mm F2.4 vs Sigma 14mm F1.8

If you're thinking of picking up a great ultra-wide astrophotography lens, chances are good you've looked at the three 14mm primes featured in this video. The old Samyang 14mm F2.8 is a classic and affordable choice; the updated Samyang 14mm F2.4 is faster, higher quality, and not prohibitively expensive; and the Sigma 14mm F1.8 Art is a lens astrophotographers have been drooling over ever since it was announced in February. So which do you pick, and why? NatureTTL's Matthew Saville took all thr...