One thing I didn't mention in my last post was for me the best and most creative photographers are usually commercial/product photographers. A lot of prep time, a lot of brainstorming and pretty big budgets results in a lot of unleashed creativity.
As for the whole "portrait" genre and the problem with language and definitions. What I do, is family portraiture. This is not the same as what say some of the greats did for life magazine which was still called a portrait. They often were hired by someone to do a portrait ( or a portrayal) of an individual. The end result was usually a pretty intriguing capture of a part of the subjects personality or what other people believed was his personality. The subject usually did not pay for the portrait and he/she may or may not have even liked it. It was turned over to editors.
What my "types" do is a picture of family members that flatters the subjects and gives a representative impression of their life or lifestyle. Actually much like the commissioned portrait painters of old. We don't delve too deeply into the pimples of the various relationships or the fact that mom is a drunk and dads a philanderer. That is someone else's job.
I guess much like a scenic photographer coming upon a scene and photographs it to look beautiful, majestic, pastoral etc but rarely is it in his psyche to try to make it ugly or even too unbeautiful. We are usually all optimists. That doesn't mean however that while he's out there and witnesses a plane crash that he would not document it and show it as the tragedy that it is. He just does not search out that kind of uglyness or reality.
Personally I try to photograph beauty and even enhance it. I'm not looking for blemishes. The beauty of the mother as she ages to middle age, the beauty and innocence of children etc etc. So I guess I have an optimistic view of a family in the way I portray them. Eisenstadt, maybe not so much. Karsh was much like my aesthetic, beautify and try to show character. But Karsh was a studio portrait photographer in the same mode as me, but would venture out to make the occasional "celebrity" portrait as well from time to time, and it's these that he is actually know for outside of Ottawa, but for which he was often unpaid and could not earn a living from. Book sales came far later.
And as for "portraying" someone and the so called definitive portrait. That is merely a myth. We are all multifaceted. We all have moods. We all have depressions, anxieties, loves and joys. We all have good days and bad days and can show both love and meanness. So a so called definitive portrait may just be in the eye of the beholder and the "capturing of someone's essence" is usually just a reflection of the viewer. I just choose to capture the good side, usually. Not always but usually.