DIY Quickdraw Strap
Ingredients: 1/4" wing nut ($1), caribiner, bottle holder with caribiner ($1), eyelet bolt ($2), utility strap ($2), seat belt shoulder strap ($5). You can substitute any spare shoulder strap (as long as it can hook together into a loop) and save yourself a few more bucks.
Screw the wing nut into the eyelet bolt
Screw the eyelet bolt into the camera. Turn until finger tight. Do not overtighten, or you will damage your camera. ( I had only one SLR body, so I'm using my camcorder for illustration purposes )
Tighten wing nut into camera, again just finger tight. Do not overtighten. The eyelet bolt should be firmly attached to the camera.
Attach the extra carabiner to the bottle holder. This larger caribiner will attach to the strap.
The smaller caribiner attaches to the eyelet bolt on the camera.
Tighten the nylon strap until it fits snugly and diagonally across your body. Attach the seatbelt pad.
Slide the buckle until it's close to the pad. The buckle will go just in front or behind your shoulder. (in front for easier removal, behind for cleaner appearance)
Clip the camera on the opposite side of the cushion.
The camera slides down the strap and behind your back when not in use. It slides quickly up for fast shooting.