Curiously, I have found that using a big camera on a tripod makes me "invisible" when doing street photography. I'm "part of the furniture" rather than an annoying pest that buzzes after people with a camera fixed to my face.

I set up by prefocussing and framing on an promising spot, shop window, ticket booth, fountain, and the like, where interesting looking people may do quirky things. I watch the unfolding scene attentively but casually and I never look at anyone through the camera. Sometimes the reflection in the lens filter tells me my "target" is in the right spot. Because I fuss with the camera controls, make meter readings, occasionally press the cable release, wind the film while standing in front of the camera, no one is certain when I have made an exposure or who has been photographed; not even the small, easily bored, transient crowd that gathers to watch what I do!

My most "conspicuous" camera is the Mamiya RB 67, a TLR is even less visible, and the 8x10 view camera may as well not be there at all. I guess the "street" psychology is that when the camera does not "chase" it's not a predator in pursuit of prey