To a lot of people, it seems difficult to be able to remember all of the parts that make a camera do what it does. What a camera does is nothing more than remembering the last time you watched CSI, (pick your favorite city), NCIS, Law & Order, Castle, The Mentalist or any other of your favorite crime scene shows.
First the formula:
The amount of light coming into the camera x How long the shutter remains open on the camera x How sensitive the sensor (digital recording device, (film in the old days)) is to the scene before it.
So lets look at each component as it relates to CSI for a moment:
The amount of light coming into the camera: When the investigator arrives at an early-morning crime scene, did he or she spend too much time, drinking or partying the night before, did they get enough sleep? If so, their eyes are not going to be open as wide, and they will be using an aperture (hole in the lens that lets the light in), of f/16, f/22 or higher. These apertures are good if you’re trying to keep everything in focus from front to back, but they limit the amount of light the camera takes in. If the investigator steps outside of the crime tape and has a quick energy drink or jolt of coffee, then returns, they are able to open their eyes wider, (an aperture of 5.6 or lower number; the lower the number, the bigger the hole for light to come in), and see “more” of the crime scene, or see the details clearer.
How long the shutter stays open. Have you ever noticed, sometimes an investigator comes back to the crime scene, because there’s something they missed? How spending time at the crime scene will spark their brain in the right direction, the “AHA” moment when they know exactly what happened? Controlling the shutter speed does that for the camera. It allows the camera to spend just the right amount of time, thinking about the crime/picture. By the time the shutter releases on the camera, the camera will have all of the information it needs to solve the case.
The sensitivity of the sensor? These are the CSI’s or investigator’s crime scene notes. If these notes aren’t right, the evidence won’t be allowed into court and the killer will go free. If the sensor isn’t set to the right setting, the picture won’t be usable as evidence. The picture could be too bright, (the juror might think it’s too easy…, the police must have planted the evidence), or to dark (the juror can’t see the connection to the suspect, so they disregard the evidence). With the right sensor, or ISO setting, the camera uses just the right amount of light, (the lens setting, aperture), with just the right shutter speed, and the perfect ISO setting to take the best picture it can.
Grab a camera, head out and “capture” that perfect image.
I hope some of this helps, and WOW, I think I watch way too much television.
Have a great day!