Ok I don't understand the whole "if you don't have a prism the binoculars would be half a meter long" statement. Because I have a pair of old Russian opera binoculars from 1970 8x25, that i refurbished and they don't have any sort of roof prism or something similar. They have only the magnifying glasses, they are very compact and considerably smaller than today's 8x25 binoculars. I know that they aren't outdoors ones but as I said they are opera binoculars and I'm just asking about your statement, because to me what you are saying isn't accurate. At least from what I seen in old binoculars, I seen some maybe 70 or 80 years old brass army model that is the same without any prism.