Photographs copyright: DAVID McMAHON
Sometimes when you're fortunate enough to be invited to a place like the Yukon, it's hard to pick one solitary highlight from an itinerary that includes many phenomenal experiences. But when Yukon Tourism organised a chopper ride out of Dawson City, I knew I was going to have a couple of hours I would never forget.
At this point, I'd just like to point out that snow-capped mountains have always been a part of my life, because I went to a boarding school in the Himalayan town of Darjeeling. But a chopper ride over the mountains is something else.
How often do you get to fly over mountains and photograph them, looking down from above? I was given the front seat, alongside the pilot - and I have to say I have never shot so many images in such a short space of time.
Give a man two cameras, two Sigma lenses, a chopper, a great pilot and a mountain range - and there's not much else that Nature can do to top that.
I was also extremely lucky with the weather. As all the locals told me, it was the first weekend all summer that the weather had been so clear right through. There were a couple of wispy clouds around the highest peaks, but they disappeared quickly into the clear blue sky.
Here's something interesting to ponder. I took both these shots with my 300mm lens, and when I reviewed the photos at the end of a very long day, I was intrigued by the very deep blue in the background of both images. The sky had indeed been blue - but it had not been the dark cobalt that you can see in the background.
Gradually, in the next few minutes, I began to realise what the answer was. We had been flying so high that I had actually been shooting downwards, onto the peak in the first shot and onto the ridge in the second.
You see, the dark blue (almost a midnight blue, if you ask me) was actually the foothills of the surrounding peaks.
That's what happens when you train your lens down on a mountain, instead of up towards it. Have a look at this final shot and you'll see what I mean about the varying shades of blue.