I know it is a widely populated opinion. However, DO NOT BELIEVE IT! You will not find any unprocessed images on magazine covers, advertisements etc.
First of all, even your smallest digital camera is always post-processing image using its own internal algorythms. Therefore, even if you would like to create an unprocessed image, it is actually impossible.
Secondly, camera often takes wrong adjustments even when all of your settings are correct. These errors shall be manually corrected.
Thirdly, even film photographers used "manual photoshop" to create their photos. For example, to correct white balance, they selected different films (simply, there were films for daylight and films for electric light). For portrait photo, they used special portrait films and lens. In order to adjust contract, they selected special low contract or high contrast paper. They even did overexposure or under exposure its parts by using their hands between lamp and paper. There are were plenty of other tricks, that allowed to do significant photo manipulations.
Thanks to the XXI century, I can do all of the above much easier, using modern Photoshop tools. :)