The farthest I have ranged a Deer is 723 yards, I use a Leica 1200 Range finder. I have however ranged cattle out to just over 900 yards. This is the first year that I have had this range finder but have not found it's limmits as of this posting. I will say that it is the most accurate and dependable range finder I have ever owned and works in all weather and even at dark if you can see it you can range it. They are a bit pricey but well worth the money.