The Rokinon 85mm f/1.4 is a cheap, fast lens with very good image quality; the only thing it lacks on Nikon bodies is autofocus. This is less of an issue when you adapt it to the Sony Nex-5N. Here's a size comparison with the kit 18-55mm lens. The Rokinon isn't a huge lens, but with the added bulk of the Nex-Nikon adapter,
I picked up a used copy of the Rokinon for $150 - it feels solid and the focus ring is well dampened. This isn't a full review, but my initial impression is that the lens represents a tremendous value given the image quality and low light performance it can deliver. Manual focus takes some practice but isn't too bad given the Nex's focus peaking and MF assist. Below are a couple of shots taken with the Nex and the Rokinon wide open.