Personally, I'd like to see what you'd do with the 8mm circular FE: 8mm review link
I use a cheaper 16mm OM mount Sigma. I've been looking for the Olympus versions of the above two lenses. My only suggestion is to be aware of how wide it is before you shoot...it's easy to get hands and feet in your shots. You might even need to move your rig forward on your helmet.
I picked up one of these yesterday. I wanted ultra-wide coverage at absolutely minimal additional weight. This little lens weighs less than 200g.
My initial impression is that it captures plenty of detail. Colours are accurate. Above all, the images are drawn in a very "smooth" way. There is plenty of detail there, and the bokeh is very nice indeed. Contrast could never be described as super-strong. The images respond well to manipulation in this regard.
On the negative side, I can confirm Stefan's findings that the lens does flare more than the Jackson Five. This is most certainly the lens' biggest weakness. I will shoot lots more today to see just how bad it is, and whether I can live with it. I was pretty brutal to the lens yesterday - I remembered hearing that flare could be a problem, so I deliberately pointed it at the sun. I was rewarded with multiple hexagonal flare spots as well as a prismatic rainbow effect. Very Perty Actually, in all fairness, it's no worse flare than I acheived with a Tokina 12-24.
I really like the way this lens draws images, and I'm delighted with the size/weight to be carried. I just need to test the flare characteristics a bit more. I think it's the old lens coatings that are causing the problem here.
Actually, in all fairness, it's no worse flare than I acheived with a Tokina 12-24.