Outdoor Camera catching dogs not people

I have my outdoor camera about 10 -12 feet off the ground, I know it said 6-8 ft but that did not capture enough angle for my yard but mainly because I didn't want someone to jump and grab it since it is only held on by a magnet . I have the activity zones set up and the sensor set to medium, to avoid draining the battery, which it still does, every 2-3 months. It picks up my dogs on the camera all the time, which is fine, but people can get all the way through my gate to the front door and back before it will pick them up, and sometimes wont pick them up at all. Is this bc of how high I put it? It also takes a while for it to load when i pull up live view on my phone, could the delay in opening the shutter be why it hardly catches anyone? I wanted a doorbell camera but they have yet to make any for this company that are wireless. Any help is much appreciated!