I've never been much of a fan of Arbus, but domenico's two posts have had me give another look.
Does anyone know what camera she used for 2 1/4 square? Or how tall she was? Online sources say she used a camera with a waist-level finder, but the point of view of her photos certainly seems high for that. As in the top two photos above. The third photo looks more like a waist-level finder to me.
Could be that I'm seeing things, but I'm curious.