For a little while now, I have been looking for a cheap and easy way to get m43 lens that gives me a really wide field of view, yet can accept filters so that I can do long exposures during the day. Yes, the Olympus 9-18 exists, however I find it too expensive for how much I would use it, and refuse to pay that much for a lens with that build quality. I finally found a solution that I am happy with though. I bought a used Olympus 9mm FE BCL for $75, and then bought a magfilter adapter with a 58mm thread diameter (so I can share filters for my 12-35/35-100 that I already own). The below shows show how the magfilter looks on the lens, what a shot looks like with a filter attached, and then what that same shot looks like after I ran it though LR and applied the Nikon 10.5mm FE lens profile. For $115 for the lens and filter holder, I'm definitely happy with the performance this gives me.