You are 12,000 feet up in a helicopter with all the doors removed, the bitterly cold wind screeching through the cabin, legs and fingers almost numb with the freezing chill, just as the sunrises from behind the snowy peaks of the Southern Alps. New Zealand's highest peaks, Aoraki-Mount Cook and Mount Tasman are suddenly lit up in the early morning sun, and the Tasman Sea to the west comes into view.

This was one of the most exhilarating experiences of my photography life. An incredible scene of extraordinary beauty, an untamed alpine wilderness, a palette of textures and colours and a scale which is hard to fathom, vulnerable as we were in that small aircraft.

Communicating with our pilot was no mean feat, as the noise of the howling wind made radio talk between us impossible. The trick is to ask the pilot to bank the helicopter both left and right so that everyone on board has an opportunity to shoot through the open doors without the rotors getting caught in the frame. The helicopter is moving fast, and there is precious little time to make composition adjustments. Preparation is key.

One significant advantage of a mirrorless camera when shooting from a helicopter is that the electronic viewfinder will clearly show the rotating blades. In contrast, an optical viewfinder will not since they move so fast. So I achieved a high success rate in eliminating the rotors from my images. Next, we must shoot at a very high shutter speed, at least 1/1000th of a second, to render the image sharp. Since everything in the scene is at infinity, a wide aperture can be used, and I chose f/3.2 for all my shots.

Since it is tough to make changes to camera settings whilst airborne - not least due to the cold - I decided to take advantage of my camera's auto-ISO function to obtain a correct exposure value in rapidly-changing lighting conditions, meaning that all I had to worry about was composition and focus throughout the flight. This technique gave me the best chance of coming away with a correctly exposed and focused composition.

As a footnote, when we returned to base, our female pilot expressed her excitement about the experience we'd just enjoyed. "That's the first time I've ever done that", she said.