Edward Steichen once said, "A portrait is not made in the camera but on either side of it."
On the surface, Steichen's words seem simplistic and obvious but, if you consider them for a moment or two, you realize how succinctly he described photographic portraiture in one, short, single sentence.
Nothing is "made" in the camera. Images, portraits or otherwise, are recorded with a camera. A painter makes a portrait. A photographer records an image. For that photographic image to be a portrait, the elements of it, i.e., those elements which can be described as being "made," are made on both sides of the camera and not by the camera itself. Painters can make portraits without subjects in front of their canvases. Photographers must point their cameras at subjects to record them and make portraits.
Painters don't necessarily need to coax, cajole, direct, or motivate poses, expressions, attitudes, and emotions from their subjects. Photographers need to be instrumental in helping their subjects project those things. Painters don't need to consider backgrounds, environments, wardrobe and more. They can simply and imaginatively paint whatever of those elements they wish to include in their portraits. Photographers, on the other hand, can only record what's in front of them. Sure, they can later change or modify those elements, but changing or modifying those things isn't the same as making them. You know, from scratch.
Painters can creatively "make" whatever kind of imaginary light they wish to appear in their portraits. Photographers must use actual light -- either natural light, artificial light, available light (natural or artificial) or a combination of any or all of them -- to record a portrait image.
In terms of form, function, and creativity, one of the few things both painters and photographers similarly do (or make) is a portrait's composition. Still, that composition isn't made in the camera. It's created or "made" by the person wielding the camera or the paint brush.
It seems to me that many photographers must think portraits, good portraits, are mostly made in the camera. Why else would so many of them go out and purchase just about every new version of camera their preferred camera-makers release if not because they believe better images, make that better portraits, are made in the camera? Course, that begs the question, "What constitutes better?" If things like higher resolution, ability to handle color and contrast, and other technical abilities of a camera are the hallmarks of "better," then I suppose "better" cameras make "better" portraits.
But if you believe, like I do, that the hallmarks of great portraiture have little to do with the technical capabilities of a camera. If you also believe, like I also do, that the most important elements of a portrait aren't made in or by the camera but are made, as Edward Steichen observed, on either side of the camera, then you're likely on the road to being a photographer who "makes" great portraits if you aren't already someone who does.
The young lady at the top is one I photographed last week in one of my 5-minute sessions. (Click it to enlarge it.) I doubt my client will use that photo or the few others I snapped which aren't the kinds of images they hired her and I to make. But sometimes a few deviations from expectations can be a good thing, even if it's mostly only a good thing for the two people responsible for making those brief deviations.