This is a killer optex 5.5mm pl mount super wide angle lens for the Super-16mm format. It thus covers micro 4/3 size chips and anything smaller. If you shoot on a GH4 and use pl mount glass then this is the perfect lens for you to get your wide shots. I just recently purchased it and then realized I've got way way way too much glass and have to cut my inventory big time. This lens sells used for up to $5,500 and I've got it listed at 1999.00 to start the auction. If you pick it up for that cheap then you've practically stolen it from me and good for you...I was foolish enough to buy it w