Quote - *"Films have much bigger dynamic range, "

*kawecki - Unless you're talking about Medium or Large Format Negative(About 3" x 4" and 8" x 10,") 35mm" refers to the size/type of film/negative, used by most Single Lens Reflex cameras.  I was'nt talking about digital...allthough you can bet your bottom dollar the same principal/technique applies!

It's not the size of the film, it's the quality of the film and how is sensible. A normal 35mm film is able to store a wider range of intensities than a normal digital camera. A 1000 ASA films handles much better dark areas than a 400 ASA film, but it is also more easily overexposed.
I am not a professional photographer, a professional photographer has many different cameras and many different films to be used for each situation.

*Quote - "after all in some way the HDRI images have to be done."

To get a 360 degree 2D Photographic image is impossible in one shot, but it does'nt take any special Film or Camera.  Fish Eye, and Panoramic Lenses will help, but what's needed is a program to help composite the seperate shots, and then Squish the Top and Bottom of the new image to map onto a sphere nicely.

Panoramic images are one thing and HDRI images are another. A panoramic image can be or cannot be a HDRI  image. Most of the panoramic images are normal images and most of the HRDI images are not panoramic images, but any other combination can exist.

*Quote - "I didn't used automatic cameras and adjusted them by hand and eye."

What tool you use to get your F-Stop and Shutter Speed is irrelivant.  You could just as well walk up to your subject with a light meter, measure the distance between it and your camera, and then calculate the Shutter Speed, but if you have an Automatic Camera doing this for you, then it will display , for you, whats going on.  Likewise it will allow you to make changes.  Automatic cameras are'nt always correct.  This is one instance where they are almost always off.

Automatic cameras are very easy to use and in most cases are ok, but it is an automatic process where the camera decides what to do and in some cases is not what you want to do.
If you are not able to turn off the automatic process then you cannot use this camera for some scenes.
With some little experience you don't need any photometer or anything, you know very well how to set the distance, speed and shutter for what you want to photograph.

Quote - I do'nt think thats geometrically sound.  I know I've heard of a Ray as being something different than a Light Ray, and in referance to a the Camera, but Cameras do'nt emit light. You need to angle you light object so that it bounces/reflects into your camera, or your scene is rendered null/black. This is sometimes confusing, but I generally think in terms of Light Rays, becasue they are a natural law of science that a render engine could'nt do without...

The path of light is symetrical for the direction. You can trace the ray paths from the lights to the camera or reverse the process and trace the ray from the camera to the light. The result is the same.
In many case the reversed path is much easy to be done. If you trace the rays from the light to the camera you will trace many rays that never will reach the camera, so you wasted your time calculating these ray. On the other side if you trace the ray from the camera you can be sure that your effort will not be wasted, because this ray always reach the camera.

Stupidity also evolves!