Mine seems to have a very good sensor. Tonight when I checked it, it took my picture as I was walking to it, at about 50 feet away. I've also gotten many pictures of robins and woodpeckers, which really surprised me. It does have narrow range it seems. You have to pretty much be directly in front of it. But it's really all in your setup. You can test it by walking around in front of it and watching the red light blink. Whenever it does, that means the sensor is picking you up, and it's going to take a picture. When the green light goes on, that means it's recording the picture on the memory card.
Do you have the sensor set to low, medium, or high? I always use high. I did get a few pictures today of just the wind blowing the tree limbs around. But not too many, so I'm leaving it set at high. The only thing I really don't like about the WGI cams, is there is not an option for a multi shot burst. They only take one picture at a time. But at least you can go as short as 15 seconds between pictures, so they still get the job done. Definitely better if you use some kind of bait or attractant.