Auto Rikenon 55mm f/1.4
Auto Rikenon 55mm f/1.4 is a manual focus prime lens for full frame cameras.
Wide open, subjects located outside the depth of field are shown very blurred. Has 6 aperture blades, this number of blades are commonly used. Having rounded blades provides out of focus circle shape closer to a circle.
55 mm lens filter diameter, commonly filter size, you have plenty of possibilities.