kansaswiderack

I have 4 leaf river cameras & I am having problems w/ one taking alot of pictures w/ nothing present. I have sent it in & tried the other cameras in the same location w/ better luck (I thought maybe there was to much movement from grass or shadows causing the blank pictures). The one I sent in they tinkered w/ but basically they were telling me to turn down the sensativity & lengthen the pause. Seemed countered productive-might be missing something traveling thru while it was in pause. Any thoughts?