"because if the focal point, the point as I understand it to be where all the light converges, was on the film plane, an image wouldn't be rendered, it would just be an indistinguishable point of light."
This understanding is incorrect... at all points on an objective lens exists all of the light required to form an mage (a portion of the total). That is why you can have a 200mm f/4 lens (50mm objective element) and a 200mm f/2 lens (100mm objective element). It is more accurate to understand objective lens area (aperture, f#) as being "stacking images."
The point at where all light converges is then where all source points from all areas of the objective element converge as a single point at the image plane. i.e. a point source in the scene converges as a point on the sensor.
This is a related diagram I made regarding DoField/DoFocus, but it shows the concept. The narrow aperture light/paths also exist w/in the wide aperture image; I just didn't include them for clarity/simplicity. Only the blue source is in true focus; and the narrow aperture image is darker (grey) because there are fewer images (light paths) focused/stacked/combined at the image plane.
