isn't apperception something like 'having an experience' or 'being conscious of experiencing' -- or (perhaps for Gendlin) when we are able to 'go inside' (introspect) and get a felt sense of our experiencing? (ownership -- it is me not someone else who is experiencing this). Without apperception there is no 'expereincing'
Following that, it seems to me that proprioception wouldn't be possible without apperception, but that not all apperception is proprioception.
I'm not quite sure what you're after, but if by a 'feeling of suspension' you're referring to a moment just prior to taking the photograph, then apperception would be you being aware of the moment where you are about to take the photograph (and everything that comes with that awareness). Proprioception would be the sense of the muscles, etc in that moment of suspension -- the level of tension in the finger required to depress the shutter, the muscles in the legs, the arms, the forehead, the weight of the camera (perhaps the physical assemblage of body/camera)… but this awareness of the 'mechanical' aspects of the body doesn't exhaust what you are aware of in that particular moment…
not sure if that is of any help
best wishes
Franc