I bought this for 360 x 180 panoramic work using a Panasonic GH4 and Tom Shot 360 panoramic head dedicated to this lens. First things first, this is a fully manual lens with no electronic connection to the camera. Aperture and focus are controlled using the rings on the lens just like the good old days! Set your camera to Av or manual and you'll be fine, but remember being fully manual there's no Exif data for the aperture or focal length (you have to provide this information to software like PTGui, and using plugins like Nik HDR Pro you'll need to provide the relative stop difference between your bracketed exposures). The other aspect of being manual is the aperture will not remain wide open until you take the shot, so you may want to open it up to compose and focus then stop it to the required aperture for the shot.The lens is all metal and very well made. The focus and aperture rings are pleasingly stiff with little chance of knocking them out of position during use. There's no hyperfocal markers on the focus scale, but with a lens like this unless your shooting very close up leaving the focus just short of infinity will ensure everything is sharp from less than a meter to infinity even with wide apertures.IQ is excellent edge to edge, although at very wide apertures it can soften a bit. The ideal range is between f/5.6 and f/8 which gives the best edge to edge performance and a deep depth of field.The resulting photographs are "full frame fisheye" with 180 degree diagonal field of view (hence the mounting of the camera on my panoramic head). Distrtion is well controlled and recent versions of LR and ACR have a lens profile that will remove the fisheye effect if that's what you want.All in all a great lens, fantastic image quality and superb value for money. Strongly recommended if you shoot MFT and want / need a fisheye.