pressing the button halfway would help for a non-moving object .. but when its moving .. then it wont work
(try to make a picture of your kitten when she is climbing your open stairs and hanging underneath it more often than standing on the stairs
)
(try to make a picture of your little baby when he/she is standing up for the first time (this might be nonmoving a bit longer .. but might still be too slow .. totally depends on your baby
)