I looked at the ones for 'hunting' and they seem to start measuring at like 30 yards and out to 1,000 yards. A good range for hunting - not so for a rangefinder camera that is already at infinity by 50 feet tops. They also say they are accurate to 9 yards either way. That's 18 feet plus/minus - the error rate covers the entire useful spectrum for a rangefinder camera! And man, they are expensive!
Great for hunting, I think...but...