The '''quick ball''' is very effective on legendary pokemon, since it has the highest possible capture rate on the first turn except for a masterball.
The '''Quick Ball''' has also been known to be able to catch lengendary pokemon, such as the lengendary pokemon, Cobalion, which is in Pokemon versions Black and White. Although because the results are not certain, we can't actually tell just how affective the Quick Ball is on lengendary pokemon.
The Quick Ball (クイックボール Quick Ball) is a Poké Ball that has a higher chance of capturing a Pokémon the earlier it is used in battle. At the beginning of the battle, its catch rate is 4x. If used on any turn after the first, it has a catch rate of 1x.