First Shooter
The first-shooter photographer is the person most laypeople expect to be handling the camera. He is the skilled photographer hired for an event who stages the main photographs, handles the photo arrangements, takes the big photos desired by clients and prepares the final photo package to be delivered to the customer.
Second Shooter
A second shooter works as part of a team of commercial photographers. His role is to take photos at an event that aren't necessarily staged or formalized. Instead, the second shooter may capture a momentary emotional moment of event-goers between formal staging or may take various candid photos of things and people to remember an event by. Instead of taking formal photos of everyone looking proper, the second shooter looks for opportunities to catch people laughing at a funny joke or holding hands quietly as witnesses to someone else's event.
Team Work
Working together, the first and second shooter as a team on a hired event will in theory capture the whole event photographically. The two angles can capture both the formal and informal images that make an event real and memorable in photography. For example, one photographer may catch a couple from the front as they proceed to the altar in a wedding. Simultaneously the second shooter will catch the length of the bride's wedding dress train from the rear as an added image element. If trained properly, both photographers will capture and event much better than one very-skilled photographer can possibly manage.
Labor Setup
Frequently, the second shooter tends to be a mid-experienced partner level for a photographer transitioning to the full professional level in commercial photography. The second shooter will very often work for the first shooter as an assistant, but more than just an equipment gopher. Eventually, the second shooter can take experience learning from the first shooter to then venture out on his own. In a sense, the labor relationship works similarly to an apprenticeship.