I am headed to Alaska on a Dall Sheep hunt. I own several pair of premium brand binoculars. They range from the full size 10 X 42's down to 10 X 25's, with a great pair of 8 X 32's in between. I will be using a backpack. What is the best binocular to take? I would like to balance the trade off between weight and great optical clarity and light transmission at twilight. Does anyone have any thoughts on this subject?

I would for sure bring the 10x42s. I backpacked for dall sheep in 2002 and I used Swarovski 10x42. I think 10x is great, as you will be glassing a long way. IMO, Dall sheep don't stand out as well as one would expect. Real sheep get stains on them from grass, shale, and mineral licks and you will see quite a few white-ish rocks that will be hard to identify at extremely long ranges. So, go with the 10x.

In low light conditions, the human pupil can expand to around 4 mm (it can be as large as 7 mm in very dark conditions), so with 10x binoculars you should have at least 40mm objective lens for low light glassing.

I don't try to save weight on my optics, because good optics can save soooooo much unnecessary walking.

Good luck on your hunt! Let us know how you do.

Thanks. I've been concerned about it and I really appreciate the feedback. All my binos are Leica models. They are a little heavy, but are an excellent brand of glass for MY eyes. I'll disregard the weight issue and go with the 10 X 42's.