Too often when setting up on a trail, folks will set up looking straight across the trail with the camera fairly close to that trail. Lag times with trail cameras from sensing motion to snaping the picture vary from nearly instaintanious for some 35mm to around 7 second for some poor quality digitals, with 1-1/2 to 3 seconds being average for better digitals.

When setting up on a trail, angle the unit on trail where it will "look" up or down the trail. Doing this, the deer, or other animal, will stay in the field of view longer, giving you a better oportunity for a better picture.