Deer don't mind the flash. I have a camtrakker, regular camera set out near a feeder, and put it on 10 minute delay. You don't want one animal taking 20 plus pictures, so if you have it at a feeder, I'd go with at least 5 minute delay, and probably 10 would be better. As mentioned, it depends on how many pictures your card will hold and how long between the times you check it.