Seeing the light, correct exposure and ISO
The next part of exposure deals with the films (ASA) or sensors (ISO), before digital we shot with film and film was being developed all over the world. Without a system to standardize the films sensitivity to light each manufacturer had their own films sensitivity and to be truthful ASA is a general term, just a starting place, the difficulty is everyone uses different equipment, and techniques to shoot and develop their film.
Because so many variables are involved with chemicals and solution strength and time in the solution, how much agitation to infinity and beyond a films speed is really just a starting place to being able to determine a correct exposure.
Likewise ISO is pretty much as arbitrary as its films counterpart. But it is a starting place. This blog deals with correct exposure in the digital age. Therefore I am not going to go into great detail about ASA which stands for American Standards Association. What it does is gives a standard for a films sensitivity to light, and the lower the number the slower the film is and the amount of exposure to light it requires, deemed slow film, vs a higher number ASA of 400 the less exposure to light to duplicate the same image density.
ISO, which stands for International Organization Standardization, hey wait a minute shouldn’t it be called IOS? Well to be sure understanding correct exposure and the quality of light, is not simple, as our eyes make it, but it does sink in once we start shooting, doing post production processing, reviewing our own images being critiqued by teachers, clients, families, or friends.
To be sure the more you practice and review your settings vs results and make detailed notes. If you are a right brained like me, taking notes is torture, it is trial by fire, after all I was drawn to photography because of the art. A great many of the worlds best photographers are left brained that are drawn to photography because of the mathematical symmetry, and then the best of both worlds dual brained people who excel in their learning curve, it is a huge advantage to be able to understand the science and express your visual interpretation of the moment all at once. These are the people I hate!! Just kidding, well maybe not! Jealous, hmmmmmmmmmm, maybe?
Amateur photographers, professional photographers alike must learn their own equipment, and how their camera and lens sees the light, to be a creative photographer.
Given two identical cameras and lenses made off the same assembly line there would be a difference. No two sensors are exactly the same, no two post production processes are the same because no two computer monitors are the same there are just to many variables involved, the difference is slight and to most not definable, however it is something to understand as you become a photon writer,
To finish this addition we will finish off with the lower your ISO setting is the less sensitive the sensor is to light, so if there is plenty of light to shoot with, the lower ISO provides a smoother reading of the photon stream being beamed through the shutter which came through the lens aperture, and therefore gives a good artistic or realistic rendering of the moment if it is correct if not it is either dark or bright. To dark and we lose data, called clipping the shadows, to bright we clip the brightest photons or clipping your highlights.
Today’s camera sensors are so advanced that we have super high ISO speeds which gives smooth recording of the light spectrum giving a amateur photographer, or professional photographer the ability to be creative photographers in extremely low light situations without a lot of noise and aberrations appearing up on your image, as we did just a few years ago with high ISO numbers.
So pick up that camera and start looking at light and shadows, the transition between the two, the direction and the angle of light and see the light!!! We just take it for granite without seeing we just take the scene in, it is similar to hearing but not listening.
Well this ends today’s addition of the Photon writer, Creative photography comes through practice, not purchase.
Michael Knapp
Irresistible Images
06-04-2011