I photographed this scene through the open door of an AgustaWestland AW109 helicopter with Canon 5D Mk 3 and Canon 8-15mm lens, set at 15mm
EXIF: f/7.1, 1/1000 sec, ISO 500
Post-processing: 15mm fisheye is as wide as it gets without getting half of the helicopter in the frame. I still got its rotor blades and landing wheel in the corners which took a while to paint out.
I used Lightroom 5.1, Photoshop CC and Topaz ReStyle to finish this shot.