The area we hunt the most consist of flat farmland bordered by river bottom, and the only time we don't hit the woods is when it is lightning. On most mornings it is realatively damp to say the least. We have had many problems with the same thing your talking about not to mention it being clear and cool when you hit the field before first light, set up, and just as the light is breaking on the horizon, a slow fog rolls in from across the field or out of the bottoms. The following condensation which appears on everything when this happens will drive you completely nuts. We have tried scope caps and covers of all sorts with no avail. I even went so far as to apply some Rain-X on one of my older scopes lens just to see if it would help out. Don't do it. I have to say that in a down pour it is great, however, in the misty fog it just seems to compound the problem.
The only thing I have actually found that works, is tissue paper and party balloons. Simply put the tissue paper inside the end of your scope, and stretch the balloon across the top. It might look silly but they will seal off better than any other covers we have found. It takes a little time to prep but once done works great. Just roll up enough tissue to fit the inside of the lens, and stretch the balloon across the top of it to hold it all in place. Generally if you work with it just a little, you can manage to keep enough of the tissue to the side as you install the balloon that it will catch on the edge of the balloon as you roll it off, and come out as you roll the balloon off.
As for the bino's, I had similar problems with them, but went to putting a 1 gal zip lock bag inside of my outter jacket with the opening looking to the side. This allows me to slip the optics into the bag and keep most of the bigger stuff away from them. Even though they are completely waterproof, it makes them much easier to keep clear. Just use a couple of safety pins to secure it in place, with a piece of duct tape doubled over the corners to reinforce the bag. Might sound pretty lame, but when hunting in adverse conditions it makes up for the trouble very quickly. They might still get damp and have a little moisture on them, but when you really need them at least you will be able to see through them quickly. As for the bag making noise, I have found that since it is mostly covered by your outter wear, and your only going to have enough of it open to allow for the optics to slip through, it is a non issue. I have had deer within 30' of me when pulling them out to look at or others or through the underbrush. They never even knew I was there.
Another thing you might look into instead of the balloons are Finger Cots. They generally sell them at pharmacies or in those dept, at larger stores. They are for covering injured fingers and such to keep moisture away. They will work better for the larger diameter scopes but generally cost a little more. As for the balloons you just have to try some to figure out which ones fit the best.
Hope this at least gives you something to work with.
