This post was originally published on February 3rd, 2012. But, I was dealing with one of my all too frequent bouts of insomnia, so I decided to update it a bit and added a few details.
The word photography is a compound word based on two Greek words, "photo" and "graphy". Translation? photo=light and graphy=writing.
So, when you boil it all down, light is a very important part of photography as we know it.
One term to keep in mind is the word "STOP". In the world of photography, it is a major component in determining how much light is being used by your camera. Increasing by one stop, doubles the amount of light, while decreasing by one stop, halves the amount of light.
Most cameras that support manual exposure, will allow the photographer to adjust the exposure in full stop, one half stop, and/or one third stop increments.
In photography, exposure is a very important part of creating a good photograph. Some photographers might say exposure is the most important part.
According to "dictionary.com" the term exposure in photography is defined as:
EXPOSURE:
- The act of presenting a photosensitive surface to rays of light.
- The total amount of light received by a photosensitive surface or an area of such a surface, expressed as the product of the degree of illumination and the period of illumination.
- The image resulting from the effects of light rays on a photosensitive surface.
Proper exposure is accomplished by combining three basic, yet very important camera settings: ISO, shutter speed, and aperture value. The combination of these three settings is sometimes referred to as "the holy trinity" or "the exposure triangle".
ISO refers to the sensitivity to light of the photosensitive surface of your camera. This is most often the sensor or film in the camera.
In terns of ISO, a STOP doubles or halves the sensitivity of the sensor/film.
The ISO used will determine the amount of film grain or digital noise that appears in a photograph. Different cameras will handle noise differently; some better than others.
Most digital cameras will allow you to control the ISO level: while, in most cases, the type of film used will determine the ISO that will be used.
Generally speaking, the higher the ISO setting, the more grain or noise there will be in the photo.
This list includes some of the more commonly supported ISO speeds in full stop increments..
Many digital cameras will support ISO settings in 1/3rd of a stop increments. Also, some cameras will support much higher ISO settings; allowing the camera to offer better low light sensitivity and performance.
Something to keep in mind: only digital cameras will allow the photographer to set the ISO. Older, film based cameras require a special film for each different ISO desired. This is one of the many conveniences photographers experience by using digital cameras.
The shutter speed refers to the length of time that the shutter curtains stay open to expose the photosensitive surface, usually the sensor or film, to light..
The shutter speed is often used to control the appearance of motion in a photograph or to freeze action. The faster the shutter speed, the less time there is for light to enter the camera and expose the photosensitive surface.
Here is a list of some commonly used shutter speeds in full stop increments:
The term aperture refers to the opening in the lens that directs light into the camera to strike the photosensitive surface.
In terns of ISO, a STOP doubles or halves the sensitivity of the sensor/film.
The ISO used will determine the amount of film grain or digital noise that appears in a photograph. Different cameras will handle noise differently; some better than others.
Most digital cameras will allow you to control the ISO level: while, in most cases, the type of film used will determine the ISO that will be used.
Generally speaking, the higher the ISO setting, the more grain or noise there will be in the photo.
This list includes some of the more commonly supported ISO speeds in full stop increments..
- 50
- 100
- 200
- 400
- 800
- 1600
- 3200
Many digital cameras will support ISO settings in 1/3rd of a stop increments. Also, some cameras will support much higher ISO settings; allowing the camera to offer better low light sensitivity and performance.
Something to keep in mind: only digital cameras will allow the photographer to set the ISO. Older, film based cameras require a special film for each different ISO desired. This is one of the many conveniences photographers experience by using digital cameras.
The shutter speed is often used to control the appearance of motion in a photograph or to freeze action. The faster the shutter speed, the less time there is for light to enter the camera and expose the photosensitive surface.
Here is a list of some commonly used shutter speeds in full stop increments:
- 1/8000th of a second
- 1/4000th of a second
- 1/2000th of a second
- 1/1000th of a second
- 1/500th of a second
- 1/250th of a second
- 1/125th of a second
- 1/60th
- 1/30th of a second
- 1/15th of a second
- 1/8th of a second
- ¼ second
- 0”5 of a second
- 1 second
- 2 seconds
- 4 seconds
- 8 seconds
- 15 seconds
- 30 seconds
The term aperture refers to the opening in the lens that directs light into the camera to strike the photosensitive surface.
The main use of the aperture values is to help control the amount of depth of field (DoF) in an image.
Depth of field refers to how much of an image, both in front of and behind, the focal point, appears in focus.
The larger the aperture; the more light is allowed through the lens and into the camera. Pressing the shutter button then opens and closes the shutter curtains; controlling the duration that the light can hit the film or sensor.
The camera's processor uses a mathematical formula involving the focal length of the lens being used. This formula is used to determine the actual size of the opening in the lens. This is more commonly known as the F number or aperture value.
A higher aperture value means a smaller aperture opening. While a lower aperture value means a larger aperture opening (see the diagram above).
I would like to refer photographers to this great video by Mark Wallace of Adorama TV. It's a very good explanation... Click here to see the video.
The following is a list of the commonly used aperture setting suported by most DSLR cameras, in full stop increments.
- F/22
- F/16
- F/11
- F/8.0
- F/5.6
- /4.5
Some lenses may offer largest or smallest aperture values. Some lenses can support aperture values as low as f/1.2(or lower) or as high as f/32 (or higher).
Although the aperture value is a major contributor to the amount of depth of field in an image, there are two other things that help determine the amount of depth of field on an image..
The focal distance of the lens (amount of zoom) and the distance between the subject and the camera also play a part in determining depth of field.
A longer lens has a tendency to provide more compression between the subject and the background. This often results in a much shallower DoF. In general, the shallower the DoF, the less is in focus in front and behind the subject.
So, in short: to achieve a shallow depth of field, a photographer will use a larger aperture (lower F-sto number), or a longer lens, or distance the subject from the background, or some combination of these three methods.
I hope by reading this blog post, some of you, learned something.
--- Mark ---
Although the aperture value is a major contributor to the amount of depth of field in an image, there are two other things that help determine the amount of depth of field on an image..
The focal distance of the lens (amount of zoom) and the distance between the subject and the camera also play a part in determining depth of field.
A longer lens has a tendency to provide more compression between the subject and the background. This often results in a much shallower DoF. In general, the shallower the DoF, the less is in focus in front and behind the subject.
So, in short: to achieve a shallow depth of field, a photographer will use a larger aperture (lower F-sto number), or a longer lens, or distance the subject from the background, or some combination of these three methods.
I hope by reading this blog post, some of you, learned something.
--- Mark ---