I'm from France and I would ask a question on a point that I don't understand, as it seems that so many people confuse (or may be I'm wrong).
On the camera, there is a symbol (a theta or phi) which is called in English "image plane".
In France some people call it "focal plane", but for me the focal plane is the plane formed of the sum of all secondary image focus points and primary image focus point (F').
This plane is the same as image plane but just in case on image coming from infinity.
For a near object placed before the object focus point (F) , the image is formed behind the focal plane, reversed, and reduced, on the image plane.
Do you agree with this assertion ? Could you tell me if I'm wrong ? (If not I don't know why some people call image plane "focal plane")
Do you have a reference course which explain that ?