Is there a single word for a person with great interest in photography but not really a photographer? who is an enthusiast for photography or atleast who is going to be one soon?
I'd suggest "shutterbug."
The Free Dictionary defines this informal word as: "an enthusiastic amateur photographer."
Semi-pro would refer more to someone who works as a photographer part-time but that isn't really his main occupation, while pro-am would imply a sort of professional-level amateur, an enthusiast who's as good as professionals in his field.