I wonder, too, if the fact that he's not waving a honking big lens in their faces and instead has this seemingly innocuous little Q2 in hand also makes a difference?
That's a great question! Similarly, that often comes up in discussions about "street photography," and whether large cameras and lenses attract attention and adverse reactions from people on the street being candidly photographed.
Many think that's true. And thus believe being stealthy/sneaky so subjects don't see you is the solution. I couldn't disagree more.
From my experiences, people on the street are incredibly perceptive. And react adversely to photographers engaging in *suspicious behavior*, rather than camera/lens size. I've seen a lot of that from people starting out in street photography.
Examples I've witnessed (and that I've done in the past) include: shooting from the hip while walking, pretending to fiddle with your camera while you sneak a candid photo of a person, looking one direction while you sneak a shot of a person in another direction, etc, etc. People are very perceptive to that and some don't like it to the point of calling you out on it. I've seen people called out on sneaking shots, and then when challenged, lie that they didn't. That just makes matters worse. At that point just own it and apologize.
Best to just square up with your subject, smile, take the shot, say thank you and move on. If challenged, that's an opportunity to have a discussion, explain what you're doing (for me that's: I'm documenting the city, or it's for my blog (when I had one)). And then hit them up for a posed portrait.
They'll often say yes.
For making impromptu street portraits, just start up a conversation with someone. Say something complimentary about their tats, glasses, hat, etc. And then ease into hitting them up for a portrait. Most of the time they say yes. Some need a little convincing. It's about establishing trust and respect. And ideally that flows in both directions
Soooo...getting back to your question, I'm guessing camera size has little to do with him making great photos. And that it's mostly about the respect and trust he exudes, and his reputation. Just speculation on my part.
Edit: Also... I've made photos of people on the street, candid and posed, with a variety of camera sizes and really haven't noticed that making any difference with respect to engagement.