I had this lens for a few months before USPS lost it. It was a pretty interesting lens and does take some unique shallow depth of field images. It was quite heavy though, heavier than it looks. A few months after I purchased it, I found in some situations there was a strange circular pattern in the bokeh. I contacted Mitakon and they confirmed it was a defect. They asked me to ship the lens to Hong Kong with economy shipping, so I did. The package never arrived to Hong Kong. There's where my story with this lens ended :(
jayleeAt least it's not the regular kind of onion ring introduced by aspherical elements, because this lens does not have aspherical elements. Not exactly sure what it is, but Mitakon/Zhongyi confirmed it's a defect.