Light weight binoculars

I know you asked about binoculars but I'm very happy with my Zeiss 10x25B Design Selection Monocular. It weighs 3.1 oz (88.6 g). It's a little pricy but the optics are great. It's small enough that I actually often have it with me to use. I had it in my front pants pocket during a trip to the Black Hills this past weekend. I got a great view of George Washington's right nostril when we visited Mount Rushmore :).

I agree with Eric; and I carry a little 4x monocular. By definition they are 1/2 the weight of binoculars, holding all other variables constant. Stereoscopic vision does not work out at that distance, so one eye is as good as two for most viewing, I think..

Coincidently it attaches to the lens of my Casio EX-Z750 camera, to increase the optical magnification from 3x to 12x; works ok in bright light.
Last month I was observing the wild monkeys in Niigata with the monocular; nice to have it.