Photographers and Cinematographers are trained in very much the same way - except there's a major difference in focus which as time passes creates two very different mindsets regarding composition.
Photographers are trained to capture a moment.
Cinematographers are trained to tell a story.
The tools are almost identical. An f-stop is an f-stop (unless you are using cinema lenses with T-stops instead of f-stops - which a T is fixed - T2 is always the same from lens to lens - whereas f-2 on a lens can result in a different sized aperture from lens to lens because f-stop calculations are part of a formula that includes focal length and diameter of your main element lens), lumens are lumens, color temperature is color temperature... etc...
A major difference is obviously shutter speed. The shutter speed of a motion picture camera (one that shoots 24 frames per second - the USA industry standard) is calculated to be 1/48th of a second. This is because before viable digital motion picture cameras existed the vast majority of films were shot on - wait for it.... that's right - they were shot on film. Motion picture film cameras use a rotating shutter. Basically a spinning disc that is 1/2 open and 1/2 mirror. The mirror part bounces the image from the lens into the eyepiece prism so the camera op can see what the camera is shooting. When the shutter is open and light from the lens is allowed to hit the film plane (where the film is exposed), there is no image in the eyepiece. So even though 24 frames are being exposed per second - actually 48 frames are. Only 1/2 are routed into the eyepiece and 1/2 are allowed to expose the film.
There are 5 (five) qualities of light that every photographer and cinematographer must learn and work with to achieve their goals. These qualities are intensity, quality, shape, color, and direction.
1) Intensity - The brightness
2) Quality - The hardness/softness - this is important regarding the type of shadows the light casts
3) Shape - The patterns of light present - which also affects the patterns of shadows cast
4) Color - Also called temperature - has several values such as hue, value, and saturation.
5) Direction - the location of the light source - important in regards to the orientation of the main subject.
These 5 qualities offer innumerable possibilities for how each variable can change the outcome of a shot. They also represent very real technical hurdles which have to be addressed - in some cases one or more of the variables - if they are fixed - can limit or definitively establish the options a photographer/cinematographer has. A great example is shooting any scene in bright sunlight, outdoors, in an environment where silks, screens, scrims, shades, bounce boards, etc... cannot be used. How can you shoot and still achieve the desired result?
The difference in looking at these 5 qualities of light as technical aspects of a photo or shot and using them to help tell a story becomes one of the places where cinematographers move into territories traditionally trained photographers typically do not tread. This is especially true of photo-journalists - who shoot events as they unfold; working as an observer and not a participant in the events.
A cinematographer is trained to see how light can be used - how it can be created and shaped - to augment the underlying emotion (or subtext) of a scene (part of the story being told). In this all 5 qualities can be adjusted to present various subtextual clues.
A great example can be found in the movie, "The Bourne Ultimatum" - after the dramatic mid-film rooftop chase and fight scene - the main character Jason Bourne is sitting on a bed talking to Nicky - his friend. There are a series of what we call OTS-ECU (over the shoulder - extreme closeup) shots - where just the actor and actress's face are in frame with a hint of the over actor/actress in one edge of the frame. These shots are used to intensify the emotion of a scene. Both actors are never shown in the same frame completely, instead there is only a hint of the secondary subject's position in one corner of the frame (the main subject of the shot being the actor whose face is being shown). The scene is cut between the two as the emotion of the scene heightens.
Here is where the "magic" of cinematography and the very subtle manipulation of reality comes into play to strengthen the underlying subtext of the scene and provide visual clues as to how we should feel about these characters at this moment of the film. Nicky - the female character - is shown in slightly warmer and softer light. The psychology behind this makes her seem more open, safe, giving, feminine, gentle. The light is also more direct - less shadows across her face - so she appears to have nothing to hide. When the shot cuts back to Jason Bourne, who is supposedly sitting on the bed next to her - face-to-face - the light is hard, casting hard shadows across his face - the light is cooler... the majority of his face is in shadow - to represent the darkness brooding inside of his character.
This is called a "cheat". He was lit with a different set of lights. And if you actually look at the direction of the light - there's no possible way (at least with our understanding of the universe) that these two people could be sitting next to each other in the same room with the same light(s) relative to each other and have the color, intensity, and quality of light falling on themselves as depicted in the shot. It's not possible but because the shots are edited they way they are and they are short - just a second or two each) and the focus is selected to suggest a confined space - the majority of movie-goers will never catch the slight of hand. They'll just remember how emotional that scene was. And THAT is how light becomes a character.
I have used light - all 5 qualities to support the subtext; from augmenting the emotion of the characters on screen to misdirecting the audience (to help build suspense or to protect a surprise that the director doesn't want revealed until later). Light - in both my work with still photography and with moving pictures - is a vital element which expresses so much more than the straight-forward presentation of the subject.