both sides

Imagine being able to see on both sides of your head... With a fish-eye, one can, almost. The world doesn't look altogether what one is used to. The new addition to the family is a Samyang 8mm f/3.5 lens (here's a review). So, using a DX sensor, this gives a 180° field of view on the diagonal with its stereographic projection. Or, in normal speak, a very wide angle with lots of distortion. Whatever it is, it's fun, and in my opinion makes for photos that are either interesting or rubbish, depending on how it's used, up to you to decide.

Wouldn't want to meet them in a dark alley. RATP security guys always look like they have a different night jobs.

Crossing over after the Tour de France. Here the horizon is mid photo, hence straightish. 

Solferino, amongst other things, home to the Socialist Party HQ. Here you get a nice feel for the fish-eye distortion where only the lines passing through the centre are straight. Less obvious in the metro tunnel where straight lines are few and far between to begin with. In my opinion, it is for this reason that the distortion works. If you look very carefully at the edge of fluorescent lights, you'll see some chromatic aberration, which I haven't processed out. Just one of those things that comes with squeezing such a huge angle into view.

So now you're in for the occasional fish-eye, let me know if it is rubbish or not.