You really need to learn and be in command of the basics of perspective, shading, color theory, and anatomy so that you can “edit” or revise the information in the photo as you use it as a point of departure or reference in your own work.
As David answered on August 18th, there are some problems with drawing and painting from photos. The lens can distort size and scale, color and shading are often inaccurate so if you don’t understand the rules of size and scale, anatomy, shading, and color, you may incorporate those inaccuracies into your work.
For example, most photographers who create reference photo for drawing manuals on anatomy, know that they can minimize the distortions (such as really big differences in size scale from foreground to background) created by the lens if they photograph the model from far away. That way, students who use photos to learn anatomy and life drawing won’t have to deal with size scale distortions and can learn to draw the figure.
However, from Vermeer and Canaletto (who both used a camera obscura) and Ingres (who used the camera lucida) to Manet, Eakins, and almost every modern artist I know have used photographic reference as a basis for paintings.
It’s really how you pick and choose what visual information is in the photo and how you translate the photo you are basing your work on.