Pentax SMC Pentax M 20mm f/4 Super Wide Angle Lens Opt Perfect

  

Optically amazing: zero fungus, no blemishes, very little dust indeed. Very tiny amount of paint wear to the aperture ring as per pics. This lens is a bit of a gem, but is just a little too'niche' for me.

Would be great for those who do a lot of interior shots, or just to get a different perspective on things.