Using the Focal Plane Indicator
Have you ever wondered what that circle with the line directly down the center of it on your camera means? If you’re a photographer, you probably haven’t even really paid much attention to it, but if you’re a cinematographer you likely have an idea of not only what it is – but also why it’s there! The symbol is a focal plane indicator, frequently called the film plane indicator or the sensor plane indicator. All three terms have the same meaning and stand for the little circle symbol with the line through it on your camera.
What is the Focal Plane Indicator?
That focal plane indicator is a measurement symbol. Essentially, it means that if you were to cut your camera in half, in line exactly with the line that is located through the circle on your camera, then you could see that it would cut right through the front of the camera’s sensor.
Why does it cut through the sensor and why is it important to know where the front of your camera sensor is? Because this will give you the exact measurement of distance from actors or objects on the set to the camera sensor.
The focal plane indicator is an important element to focus pullers which helps them to mark exact distances between the talent on set and the camera sensor to pull focus.
Using the Focal Plane Indicator to “Hit the Mark”
Perhaps you’ve heard the terminology before, when the cinematographer asks the actor to stand on a mark on the floor and says, the actor “Hits their mark.”
This means that when the actor is on that exact mark, they are a specified distance from the focal plane indicator to the set or, in other words, they are “in perfect focus.”
As a cinematographer, you’ll use the focal plane indicator to help you measure more precisely the focusing distance from your camera sensor to the subject.
You may have thought that the measurement of focus distance is captured from the front of the lens to the subject or the back of the lens, but it’s actually captured from the camera sensor .
This is why the focal plane indicator is provided as an easy to visualize reference of the exact measurement from camera sensor to subject.
Finding the Focal Plane
The focal plane indicator is almost obsolete with all the new digital camera options and advanced features, but pulling manual focus is still something that is important for cinematographers to learn.
In fact, focus is really the cornerstone of cinematography representing the foundation upon which so much knowledge is learned and gained.
Understanding how to use the focal plane indicator can help you to maintain sharp focus regardless of the setting or surroundings on the set.
Measuring focal distance manually, or manually pulling focus is important to understand as it will help you to later grasp other concepts that build off this one.
Thus, finding the focal plane can be achieved once you’ve measured the subject focal point to the actual focal plane indicator on your camera. This is not a measurement of your camera lens tip to the subject! It’s always a measurement of the focal plane indicator to the subject.
Using the focal plane indicator to pull focus is really about taking your time and learning to master the measurements. To achieve critical focus, make sure that you are measuring out each focal point and marking your measurements as they relate to the focal plane indicator and you’ll be a success!