
I was really excited about the Zhongyi Optics Mitakon 55mm f/2.8 1-5x Macro. Not only does Zhongyi (aka ZY Optics) make some of my favorite extreme lenses (such as the Mitakon Speedmaster 50mm f/0.95), but this one offers a pretty unique combination of extreme properties.
First of all, the Zhongyi Optics Mitakon 55mm f/2.8 1-5x Macro offers obscene levels of magnification, from 1x all the way to 5x (also referred to as a reproduction ratio of 1:1 to 5:1). On top of that, while it's also available for APS-C and full frame cameras, it covers the image circle of medium format cameras without any vignetting.