Here are some examples of how this lens behaves, especially in astrophotography and infrared photography. The tested lens is Sigma 50mm F1.4 DG HSM...
Sony Zeiss 35mm 1.4 Distagon It is not sharp and clear from corner to corner. Infrared photography, not recommended.
Amazing results shooting with a DSLR camera and a lens, or a DSLR camera and a small telescope.