Result ... I'm a owner of a Minolta 16mm F/2.8 fisheye since 1 week.
I have only found time tonight to go outside and experiment the lens in real world.
Picture taken at ISO 200, with Fill light cranked at maximum to do some in one shot HDR.
I haven't realized if I pay attention to the horizon, image can be really not distorted that much. (but on the picture bellow, I'm not perfectly at the good level)
Compare the the Zenith (that cost 1/3 of the price), the Minolta looks fully usable at F/2.8 with incredible details. The lens is not that bigger and weight just a little more too. The leather hood is not that convenient ... but I'm use to it with the Tamron 14mm F/2.8.
I probably will try other shot in the next days. But for now, I know that I will sell my Zenith on ebay this weekend with a M42 Minolta confirm focus on it.



Regards,
Frank