degruyl
Just this guy, you know?
Are you thinking about pocketing the camera with the lens mounted on it, or pocketing just the lens?
I use my jacket pockets to carry my camera with a lens on it, usually either a 35mm or 50mm lens. Extra film goes in a different pocket, and I rarely walk around with an extra lens.
If I am out shooting conciously, I take the Mamiya 7, and two lenses. The extra lens and film goes in a pocket, the camera goes on my shoulder.