So, why shoot with a wide angle lens? It seems kinda obvious, but there is more to it than just being able to capture more in a photo. The perspective will also give the image a unique and expansive feel compared to a more compressed or natural look that a standard or telephoto focal length will give your photos. It also gives you the ability to shoot longer shutter speeds without blur or being able to shoot 20 second exposures of the stars without having star trails emerge in the final image due to the rotation of the Earth.
Great, you know why I love using wide angle lenses for certain things, but why do I specifically like this one? To start I want to talk about the obvious features. This lens is completely manual putting the control in your hands literally! I set the focus and the aperture setting by twisting and turning the rings to where I want them. This makes it a challenge to use at first, but you get used to it quickly and it becomes more natural and gives a physical connection with what your settings mean. Understanding that focusing on things can be done through examining the distance you are from them and how the aperture closing immediately darkens the viewfinder and makes more things come into focus.
The build of the Rokinon is very solid with plenty of resistance on the focusing ring which I find desirable for a lens of this focal length. (I don't find myself wanting it to change focus all that much) The aperture dial has a very distinguishable click to each step giving an audible and physical indication of its setting. The lens is made of dense plastic and metal making it hefty in addition. All of these things make for the lens being a pleasure to handle, but they account for nothing if the image quality is not good.
To put it simply, the images are as good as if not better than I had expected to come from this Rokinon lens. I knew when I purchased the lens that Rokinon makes some very sharp lenses, but I didn't quite expect them to be so good with this one. The detail that comes from this lens when correctly focused is incredible. The distortion is also very low which has made me very happy as setting up the lens's correction in Lightroom can be difficult to do as there are no presets for it. The one thing that I saw it struggle with was some chromatic aberration in the corners in high contrast situations. Here are some images to demonstrate what you may see coming out of the Rokinon 12mm for Micro Four Thirds.
Here are my final thoughts. Take it for what it is but at $300 for a 12mm f/2.0 lens is really the best option for a budget. I love it for what it is while it may not have autofocus or it might not be the absolutely sharpest lens out there at this focal length and it has some issues with chromatic aberration, but at the end of the day it costs a whole lot less so that you can do a whole lot more with it! It is fast, fun and affordable that is why it is my favorite wide angle lens and possibly my favorite lens for micro four thirds as of right now!