Hey GV, that really depends. Prior to last week it was either iphone, Rolleiflex 2.8, or a 645z. I just picked up a Fuji X-Pro2 and it's kind of amazing I have to say. I only have a fixed 23mm for it so cannot do any telephoto CU shots like some of the other guys get. That's the only drawback for now. There has been a steeper learning curve w/this camera than I was expecting but overall I'm impressed w/it. I took a whole bunch of shots of One Manhattan Square the other day and didn't realize the focus was set to manual ( the camera has a hybrid viewfinder meaning you can opt to use the optical viewfinder and turn off the EVF to save battery and this was the setting I was using. I had also turned off the audio alert which would have told me it was or wasn't focusing but if you want to shoot discreetly it needs to be off). I thought the diopter was just messing w/me but turns out all the pics were out of focus and so did not post them. Gotta say, it's really fun to shoot w/this little guy. I have a 5x7 view camera but I have yet to bust that out on the architecture - definitely not a camera you want to walk around with all day.
Above pics are all done w/the Fuji. Dec '16 Jan '17 were 645z (again, only have a WA lens for that beast)