"We call them smartphones, but the phone is the least important part. I would love to be the one who comes up with a new name for these," says Dan Rubin, arranging the four sleek somethings delicately on the table, weighing each in his palm. "I take smartphone cameras very seriously, and I have done ever since the iPhone 4 came out, which was the first phone camera that was good enough for practical use."

That was in June 2010, and Rubin traces the worldwide surge in mobile photography to that release, combined with the launch, four months later, of Instagram. "That was serendipity on a massive scale. That combination is what got me shooting every day – it's what made me a professional photographer."

Rubin is a renaissance man for the digital age, working in software and product design, and pioneering a serious, professional approach to smartphone photography, which he considers no less rewarding than taking pictures on his Canon 5D Mk II. "These are the most used cameras in the world now, and because those photos are all being shared, we are seeing more of the world than ever before, which I think is fantastic. You can do a whole lot with a camera phone; under the right conditions with the right light, the right framing, the right focus, you wouldn't necessarily be able to tell a photo wasn't shot on a big camera."

Smartphones have already rendered point-and-shoot cameras almost obsolete, and Rubin thinks they are now even threatening the DSLR. "Software intelligence is where they can potentially be ahead of Canon and Nikon, and already are in some respects. People look down on mobile photography, or say it's lazy, but camera phones encourage us to take more photographs, and I think the more we take photographs, the better photographers we'll be." The theory certainly works for Rubin, whose half-million-odd Instagram followers are constantly shocked that his photos are taken on phones. "It doesn't matter what hardware you have," he says, "the important thing is learning how to see."