I do not think it is PS. if it was done from camera default setting, it is the parameter that is designed for the all mechanical part of the camera, such as shutter, aperture, which are depends of the camera man's photo taken experience of setting the proper Speed and Light for the best result. So the original picture done with out PS is the best one to tell, the cameraman’s skill and experience, this is my opinion, PS is just a software manipulating the Bits and Bytes of the 1 and 0 format in the computer file. It is not a photo taking skill.
By the way,
I am a new camera learner. I have a Canon AE1 SLR back in the 70's (Not DSLR). In those day cameraman must have cretin skill to make good picture, I may be out dated. That is why I need to understand why Digital photo need PS