In general, salaries for academic physicians are lower, often much lower than those in private practice. However, the benefits are often better, and the prestige of an academic position allows many people to have other sources of income, such as books, pharmaceutical contracts, etc.
I thought the same way in medical school but once you get out you realize that the money will come.
There is a huge range of salaries within all specialties, between academic and private. Please take it from me that now is not the time to consider such things. People who choose a field of medicine for the money are kicking themselves in the butt. If you choose something you enjoy, you are liable to find lots of different ways to make money doing it.