AutoCAD and the like are used for 'Computer Aided Design' (the CAD part in many cad applications), this means you can model a 3D object and then create detailed documentation from that model such as 2D drawings, parts lists and arrangements etc.
Blender, Maya (Autodesk) and others are more for just conceptual 3D modelling where the model is more used for things like rendering 3D animations (Toy Story for example) and other 3D scene representations and models for games etc. They don't lend themselves well to CAD type work as they contain no 'data' and the software isn't designed for producing documentation like CAD software.
Photoshop is for editing pixels only like photographs, and other 2D images like simple graphics designs and logos etc. You can view a screen capture of a 3D model to change colours etc but there is no '3D' in app's like Photoshop (or Illustrator).
So, you need to work out what field you need the software for (Conceptual/Games or CAD) then focus further into the specific discipline before choosing any of the available software as they all specialise in certain areas that don't always crossover to others in a lot of cases.
hth