The Lensrentals team created world’s widest angle fisheye lens, taking 270 degrees photos, means the lens sees behind itself.
The lens is unique. It’s a prototype C-4 Optics 4.9mm f/3.5 circular fisheye, a massive lens giving a 270-degree field of view, meant for immersive video and specialty shots.
To give you an idea of what 270 degrees means, the lens sees behind itself. An ultra-wide 15mm fisheye lens gives a 180-degree field of view while an 11mm rectilinear lens is less than 120 degrees.