For your comfort we have implemented a "group" system much like the zones used in airports for lining up. This way, select photo ops are subdivided into smaller sessions called groups where you may, for example, be lining up for Group 1 starting at 5 PM, or Group 2 at 5:15 PM, or Group 3 at 5:30 PM, etc.
This allows you to only arrive a few minutes before your group start time as printed on your ticket, rather than wait an hour or more. On-site we will usually have a PA system and TV's that will show which group we are now "boarding". Please always check on-site to make sure the time for your photo op has not been changed!