When I look at a photograph I have taken I believe that I see a bit more than someone who has not taken it. And this is especially so if it is a family portrait.
There is also the important factor that time plays in the taking of a photograph. That first photograph that Daguerre took of a man having his shoes shined with what looks like an empty Paris Boulevard is not so. The exposure time was minutes long. Any movement behind that man would have been blurred. It has been said that Daguerre paid the man not to move.
Shutters also affect how a photograph is seen. Compur shutters like the one in Rolleiflexes close to the taking f-stop. This means that the whole photograph is about a moment in a precise time. Single lens 35mm film reflex cameras are not at all like that. Depending on the focal plane shutter involved a slit on a curtain (metal or cloth) moves horizontally or vertically. If you know that you camera shoots images that are upside-down on a group shot that is taken from head to toe, vertically on a camera like my cloth shutter Pentacon-F the heads of your subject are exposed before their feet. In Einsteinium time the faces are older than their feet. My photographs here were probably taken at 1/60 second.
There is another facet of time that hits me as the portrait photographer when I look at a portrait (two here) that I took of my Rosemary in Morelia, Mexico perhaps in 1969. She was alive. She was vibrant. I posed her with not much instruction. I was learning then. I was photographically unsophisticated. The two contact sheets have two different films. It would tell me that I used my Pentacon-F and my other camera an Asahi Pentax S-3. By then I had a little lab in our home so I processed the film.
It is most difficult to explain the feeling that I get that my Rosemary was a live human being now gone.