Here is what I was told by a well known deer manager. He had managed properties all over the country for one of the biggest consultants. I think I trust what he says. LOL
"The best time to run a photo census is as late in the summer as possible (so antler development is near complete), 2) yet before any acorns begin to fall (acorns outdraw any other food source--deer will stop coming to the camera bait once acorns begin to fall).
For me, I like anywhere from the first of August through mid-September. Antlers are almost fully developed by early August and acorns begin to fall in mid-September. Just remember that any food-source bait must be completely removed at least 10 days before the start of bow season.
Once I determine the camera locations, I pre-bait the location (keep an active pile of corn) for at least 10 days before I start the census (to get deer accustomed to using the site), then I place the cameras and run the census for at least 10 days. In 10 days, you will get pictures of the vast majority of deer using the area (90+%).
Minimum camera/bait locations are 4 per square mile, or one per 160 acres (quarter square mile). I literally draw a one square mile square on a map, divide it into four equal quarters, and then pin-point a camera/bait site near the center of each quarter-square. "