Some photographers find it pretty difficult to focus everyone to the perfection. For instance, when you try to capture a group photo at a wedding, a person or an important object like bouquet can appear blurred due to poor focusing. You shouldn’t let such thing happen as an enthusiastic photographer.
The best way to overcome such mishap and get everyone in focus is to determine the Plane of Focus. Assume that there is a vertical plane in front of you and all the people in the group must be placed on the same plane. If one person steps forward or backward, he or she will be out of focus.
The purpose of determining a Plane of Focus is to focus on every individual perfectly and make them visible nicely.