I use this lens to take hemispherical (180 degree) coastal photos for work to determine the level of shade in the tree canopy, this is just what I need and it works great. Note that for a Type-C sensor you need a Sigma 4.5, not an 8mm (full frame) sensor. Both lenses are excellent for this type of work.
Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras
76 Review
Canon EF 50mm f/1.8 II Fixed Lens - Discontinued by Manufacturer
93 Review
Nikon 35mm f/1.8G Auto Focus Lens for Nikon DSLR Cameras - Black (Model 2183)
125 Review
New Nikon 18-105mm Vibration Reduction π· Zoom Lens with Auto Focus for Nikon DSLRs
104 Review