Do you know the secret formula of F Stops, Shutter Speeds and ISO?
It's a fact that the interplay of F Stop, Shutter Speed, and Focal length of your lens is crucial to the final photographic image you create. Yet, it is surprising to find out how few photographers really understand the interaction among these three factors.
Before we discuss how the parts fit together, we will first describe each separate factor.
F-stops
While it is a little joke we all make, they are actually named after their inventor whose name began with an "F".
The F stops refer to the setting on the diaphragm of the lens, controlling the amount of light that the lens gathers.
Shutter speed
Film cameras utilized a variety of types of shutters that controlled the amount of light that hit the film by controlling the length of time the light was allowed in. Today the same principle applies, but with digital cameras the light hits the "Digital Image Capture" component in the camera.
ISO
When film was used, a standard was needed to determine how much or how little light is necessary to create an image on the film. Various "speeds" of films were produced which differed in their ability to capture light. The term for that standard was ASA, from American Standards Association. A new term, ISO (International Standards Association), became popular a few years ago.
Even though we don't use film anymore, we do have the ability to set a "film speed" in our new digital cameras. My understanding of the particulars is that it is actually an electronic change to the DCD (my own term, there are CCD's and other chips, but for this article their names are not important)
Later in this article we will discuss the use of the ISO to attain a particular result.
Focal length of Lenses
What we will do in this article is show you how all of these elements come together to achieve desired effects depending on requirements of the assignment.
EXAMPLE 1
We are outside- bright and sunny.
The subject is far away, and we will use a long telephoto lens to capture the image.
We will hand hold the camera. No tripod.
We need a fast shutter speed to keep the camera from shaking. You can't totally depend on "stabilizer" lenses.
Setting ISO to 400 will usually allow Shutter Speed of 500-1000 with F Stop at F11 to F15.
In this next example, you might have problems taking pictures of your subject.
EXAMPLE 2
We are outside, cloudy, not very bright.
We want to use a long, telephoto lens to capture a subject far away.
We will hand hold the camera. No tripod.
We need a fast shutter speed to keep the camera from shaking. You can't totally depend on "stabilizer" lenses.
Now you have to make choices-
a. if you want to maintain your shutter speed, you could increase the ISO.
b. reducing the F Stop (opening the lens) will also reduce the amount of area that is in focus (Depth of Field).
It's starting to get a bit complicated, so we'll explain how these elements relate to each other.
Increasing or decreasing F Stop one full stop would be 5.6 to 8, or 2.8 to 4, or vice versa.
If you increase shutter speed from 1/125 of a second, to 1/250th of a second, or from 1/1000th of a second to 1/2000th of a second, you reduce the amount of light to your film or chip by one half, and if you decrease shutter speed from 1/250 second to 1/125 second, or 1/2000 second to 1/1000 second, you double the amount of light getting to the film or chip.
Equation: If you increase your F Stop from F8 to F11 you "Lose" one full stop of light.
Increasing shutter speed from 1/500 to 1/1000th of a second results in "losing" one full stop of light.
If you "Double" your ISO from 400 to 800 or 800 to 1600, you gain one full "Stop" of light.
Important note: "Stops of Light" is the terminology we use whether we are discussing the effects of working with ISO, F Stops, or Shutter Speeds.
Relationships Between Elements
Each of these elements can be used to control the camera settings. Control Depth of Field (amount of area in focus). Control movement, stop movement, allow movement to create effects. Use ISO for controlling amount of light.
In Real Situations
If you have your lens set at F8 and 250th of a second Shutter Speed and you need to open your lens to reduce your Depth of Filed, for the purpose of making your backgrounds out of focus, open your lens to F4, and increase your Shutter Speed to 1000.
In this example you opened your lens 2 stops, as well as increasing your Shutter Speed to 1000. From 250 to 500 doubled the Shutter Speed, then from 500 to 1000 doubled the Shutter Speed again.
If in the above scenario you were using an ISO of 800, you could reduce the ISO to 400, thus reducing the light by which would allow you to only increase your shutter speed once (double), from 250 to 500.
If you are using your camera on the automated "Program" setting, you are not taking full advantage of the adjustable controls of F Stop, ISO, and Shutter Speed that you can combine to unleash your creativity.
Your creativity will take a quantum leap if you learn all that these settings can do.
At various times I have been thought of as a critic of "Photojournalistic Style" photographers. Believe me, I have nothing against them or any other "Professional" photographers who have not taken the time to learn the simple technical information I present here.
So many eager individuals, with a love of photography and some small successes, decide to jump into the business of Professional Photographer, before they know the basics of what it takes to create the beautiful pictures that become treasured records of their clients' life events.
If friends and family tell someone that they take great pictures, that they have a good eye, that's not enough of a qualification to succeed as a Professional Photographer. Are they creating the best images possible by just using their natural artistic or creative ability? Probably not. If we go to the barber, or the Dentist, or Physician, we expect expert treatment. As Professional Photographers, we should strive for expert achievement, too.
How the elements discussed here work with your electronic flash will be in our next article.
It's a fact that the interplay of F Stop, Shutter Speed, and Focal length of your lens is crucial to the final photographic image you create. Yet, it is surprising to find out how few photographers really understand the interaction among these three factors.
Before we discuss how the parts fit together, we will first describe each separate factor.
F-stops
While it is a little joke we all make, they are actually named after their inventor whose name began with an "F".
The F stops refer to the setting on the diaphragm of the lens, controlling the amount of light that the lens gathers.
Shutter speed
Film cameras utilized a variety of types of shutters that controlled the amount of light that hit the film by controlling the length of time the light was allowed in. Today the same principle applies, but with digital cameras the light hits the "Digital Image Capture" component in the camera.
ISO
When film was used, a standard was needed to determine how much or how little light is necessary to create an image on the film. Various "speeds" of films were produced which differed in their ability to capture light. The term for that standard was ASA, from American Standards Association. A new term, ISO (International Standards Association), became popular a few years ago.
Even though we don't use film anymore, we do have the ability to set a "film speed" in our new digital cameras. My understanding of the particulars is that it is actually an electronic change to the DCD (my own term, there are CCD's and other chips, but for this article their names are not important)
Later in this article we will discuss the use of the ISO to attain a particular result.
Focal length of Lenses
What we will do in this article is show you how all of these elements come together to achieve desired effects depending on requirements of the assignment.
EXAMPLE 1
We are outside- bright and sunny.
The subject is far away, and we will use a long telephoto lens to capture the image.
We will hand hold the camera. No tripod.
We need a fast shutter speed to keep the camera from shaking. You can't totally depend on "stabilizer" lenses.
Setting ISO to 400 will usually allow Shutter Speed of 500-1000 with F Stop at F11 to F15.
In this next example, you might have problems taking pictures of your subject.
EXAMPLE 2
We are outside, cloudy, not very bright.
We want to use a long, telephoto lens to capture a subject far away.
We will hand hold the camera. No tripod.
We need a fast shutter speed to keep the camera from shaking. You can't totally depend on "stabilizer" lenses.
Now you have to make choices-
a. if you want to maintain your shutter speed, you could increase the ISO.
b. reducing the F Stop (opening the lens) will also reduce the amount of area that is in focus (Depth of Field).
It's starting to get a bit complicated, so we'll explain how these elements relate to each other.
Increasing or decreasing F Stop one full stop would be 5.6 to 8, or 2.8 to 4, or vice versa.
If you increase shutter speed from 1/125 of a second, to 1/250th of a second, or from 1/1000th of a second to 1/2000th of a second, you reduce the amount of light to your film or chip by one half, and if you decrease shutter speed from 1/250 second to 1/125 second, or 1/2000 second to 1/1000 second, you double the amount of light getting to the film or chip.
Equation: If you increase your F Stop from F8 to F11 you "Lose" one full stop of light.
Increasing shutter speed from 1/500 to 1/1000th of a second results in "losing" one full stop of light.
If you "Double" your ISO from 400 to 800 or 800 to 1600, you gain one full "Stop" of light.
Important note: "Stops of Light" is the terminology we use whether we are discussing the effects of working with ISO, F Stops, or Shutter Speeds.
Relationships Between Elements
Each of these elements can be used to control the camera settings. Control Depth of Field (amount of area in focus). Control movement, stop movement, allow movement to create effects. Use ISO for controlling amount of light.
In Real Situations
If you have your lens set at F8 and 250th of a second Shutter Speed and you need to open your lens to reduce your Depth of Filed, for the purpose of making your backgrounds out of focus, open your lens to F4, and increase your Shutter Speed to 1000.
In this example you opened your lens 2 stops, as well as increasing your Shutter Speed to 1000. From 250 to 500 doubled the Shutter Speed, then from 500 to 1000 doubled the Shutter Speed again.
If in the above scenario you were using an ISO of 800, you could reduce the ISO to 400, thus reducing the light by which would allow you to only increase your shutter speed once (double), from 250 to 500.
If you are using your camera on the automated "Program" setting, you are not taking full advantage of the adjustable controls of F Stop, ISO, and Shutter Speed that you can combine to unleash your creativity.
Your creativity will take a quantum leap if you learn all that these settings can do.
At various times I have been thought of as a critic of "Photojournalistic Style" photographers. Believe me, I have nothing against them or any other "Professional" photographers who have not taken the time to learn the simple technical information I present here.
So many eager individuals, with a love of photography and some small successes, decide to jump into the business of Professional Photographer, before they know the basics of what it takes to create the beautiful pictures that become treasured records of their clients' life events.
If friends and family tell someone that they take great pictures, that they have a good eye, that's not enough of a qualification to succeed as a Professional Photographer. Are they creating the best images possible by just using their natural artistic or creative ability? Probably not. If we go to the barber, or the Dentist, or Physician, we expect expert treatment. As Professional Photographers, we should strive for expert achievement, too.
How the elements discussed here work with your electronic flash will be in our next article.
About the Author:
Do you aspire to be a Professional Photographer? Bob Kahn, Master Photographer, offers free lessons starting with basic technical elements, plus techniques of posing, lighting, and composition, and how to put it all together to become a successful professional photographer.
