>On the film I will have 1/2 of the frame height; >On the digital CCD it will be 3/4 of the CCD height, >so "effective" magnification aclually arise; >Where am I tricking myself?
Here's how I understand it.
Your lens produces an image circle of a particular size inside you camera body. When you use film, that circle is cropped to 36mmx24mm. With a DSLR with a 1.5x cropping ratio, the same image is just cropped tighter. The actual image size will on the film/CCD plane is the same in either case, just the amount that falls on the sensor (film or CCD) is different.
It seems to me that what is more critical than image size or cropping factors is the ability to enlarge. If you put a new film with twice the resolution in a camera (and the lens to match it) then you'll get bigger enlargements even though you might still be at the same reproduction ratio as your with your old film.
The interesting question is how CCDs compare to film in this department.