Undocked, natural standard poodle tails are long and full. They usually curl to some extent and multiple tail styles may be found in the same litter. Some are fairly straight, some make a full curl over the back and some are held out behind them in a gentle arch.
This little boy is one of Eliza's puppies. He is a brindle parti who is 5 months old in this series of photographs. Natural tails act as a counter balance and rudder when dogs are running and playing. Notice how he holds his tail to help him maneuver.
Poodles use their tail to express emotion, to communicate with people and other animals, to help them balance, and to act as a rudder in the water. The length of the natural tail varies. Long hair at the end of the tail does make it look longer, should you want your poodles tail to appear shorter, trim the hair off at the end of the tail. We do not dock tails.