Is this model the lightest weight in the premier series?
You will have to check the Nikon specs to answer the weight question. I think Nikon makes an 8 x 42, which should be lighter than the 10 power. That said, I really like my binocular. I have used many brands, and like this Nikon better than my older Zeiss and Swarovski. I use mine for birding and for hunting, and have carried mine all day for ten days in Zimbabwe, with no discomfort. Nikon Premier binoculars are top of the line in my view. If you plan to use one primarily for birding in forest, at fairly close range, I would get an 8 power. If you will use it for hunting in open terrain, for use in birding for shorebirds, waterfowl or in open terrain, the 10 power is superior.