Focal length: distance between center of lens and the point where it’s able to focus
Longer focal lengths = less bending of light, removes depth (moon close to mountain), called telephoto, used for isolation and focus on a single subject,
Shorter focal lengths = extreme bending of light, adds depth (person seemingly far away), called wide angle, used for landscape, architecture,
Moving back and zooming in (adding focal length) OR moving front and zooming out (reducing focal length, going to wide angle) tries to achieve the same thing but switches depth of field
ISO, Aperture size and shutter speed control exposure of the scene (not too bright or not too dark, or bright or dark based on the story you are trying to tell)
Aperture: the physical size of the opening allowing light inside. Switching from a f/2.8 to f/4 is a 50% reduction in light.
Faster shutter speeds go with larger aperture sizes and vice
Large apertures creates shallow depth of field(subject in focus but background blurred)
Shutter speed: the time for which the film is exposed to the light, switching from 1/200s to 1/100s is 50% increase in light allowed
Longer shutter speeds may be required in dim lighting to increase the amount of light collected but motion may be distorted
Short shutter speeds are useful for a fast moving subject, when you want a very quick fraction of light frozen in time, hence the fast moving subject can be in focus and the background can blur
Normal walking = 1/50s, sports = 1/500 to 1/1000s,
With a wide lens, slower shutter speeds can work, but with a telephoto lens, slower shutter speeds lead to motion blur
Stability(mounting, clicking the shutter button, image stabalization) also introduces blur at lower shutter speeds
ISO: think of ISO as a sieve - too fine, you might not get enough light, too coarse - you might get too much noise or unwanted elements. It’s the sensitivity of the sensor to light
Brightness or exposure histogram - histogram created by using the grayscale values (0=pure black, 255 = pure white) of all pixels of the frame. Left skew = underexposed frame (most pixels have darker greyscale values), right skew = overexposed
Some frames may require over or under exposure, night sky, snow
Histograms can also be created for individual color channels to see if any one color is dominating
If the histogram crashes entirely to the left or right all information is lost, frame is useless
Exposure stops = linear increase in light collected. Ex 0EV and 1EV (double the amount of light),