i use SR300 on my robot for obstacle avoidance

my ros is indigo and use official package for the camera

i put the robot afront of a wall, at first the camera detect the wall just as my lidar detected, the distance are almost the same

but waite a little longer time , the camera detect the wall much closer than the lidar detected, as show below

after i restart the launch file, it works fine again.

by the way i keep all the parameters as default

much thanks anyone can help