1) ISO
2) SHUTTER SPEED
3) APERTURE
4) METERING
1) ISO ( what is ISO
In tradition photography ISO was the indication of how sensitive a film was to light. It was measured in numbers.The minimum of ISO speed is 100 and the maximum is 64 000. The lower the number the less sensitive your camera is to light and the finer the grain. Higher ISO settings generally used in darker situations to get faster shutter speeds.100 ISO is generally accepted as 'normal'. Most people tend to keep their cameras in 'auto mode' where the camera selects the appropriate ISO setting depending upon the conditions you are shooting in but most cameras also give you the opportunity to select your own ISO also.
About Auto ISO.
This mode sets the ISO speed automatically between ISO 100-800 to suit the shooting mode and ambient light level. For flash and <M> (manual) exposures, ISO 400 is set. When you press the shutter button halfway, the automatically-set ISO speed is displayed in the viewfinder and on the LCD monitor
ISO Speed Guide ( canon 1000D)
1) 100/200 - sunny outdoors
2) 400/800 - overcast skies, evening
3) 1600 - night or dark indoors
A lower ISO setting is used when capturing overly bright sense, since it reduces the light sensitivity of image sensor. This is ideal when shooting at the beach, on a ski slope, or under the midday sun. A higher ISO settings is often used when shooting under dimmer conditions ( cloudy days, indoors ) since it increase the light sensitivity of the image sensor.
2) SHUTTER SPEED
Shutter speed is the amount of time that the shutter is open. In film photography it was the length of time that the film was exposed to the scene you are photographing and similarly in digital photography shutter speed is the length of time that your image sensor 'sees' the scene you are attempting to capture. Shutter speed is measured in seconds. The bigger the denominator the faster the speed. 1/1000 is much faster than 1/30.
fast shutter
Shutter speed is the amount of time that the shutter is open. In film photography it was the length of time that the film was exposed to the scene you are photographing and similarly in digital photography shutter speed is the length of time that your image sensor 'sees' the scene you are attempting to capture. Shutter speed is measured in seconds. The bigger the denominator the faster the speed. 1/1000 is much faster than 1/30.
medium shutter
slow shutter
If using a slow shutter speed (lower than 1/60) you will need to either use a tripod. When considering what shutter speed to use in an image you should ask yourself whether anything in your scene is moving and how you would like to capture that movement. If there is movement in your scene you have the choice of either freezing the movement or letting the moving object intentionally blur.
To freeze movement in an image you must choose a faster shutter speed, and to blur movement in an image you must choose a slower shutter speed. When taking a photo of a waterfall and want to show how fast the water is flowing, taking a shot of a racing car and want to give it a feeling of speed, in all of these instances choosing a longer shutter speed will be the way to go. However in all of these cases you need to use a tripod. Another thing to consider when choosing shutter speed is the focal length of the lens you are using. For examples, if you have a lens that is 50mm 1/60 is probably okay but if you have a 200mm lens, you will probably want to shoot at around 1/250.
3)APERTURE
Aperture is the size of the opening in the lens when a picture is taken. The aperture that you set impacts the size of that hole. The larger the hole the more light gets in and the smaller the hole the less light. Aperture is measured in 'f-stops'. For examples f/2.8, f/4, f/5.6, f/8, f/22.
DEPTH OF FIELD (DOF) is the amount of your shot that will be in focus. Large depth of field means that most of your image will be in focus whether it is close to your camera or far away. Aperture has a big impact upon DOF. Large aperture ( it is a smaller number) will decrease DOF while small aperture ( large number ) will give you larger DOF. Small number mean small DOF and large number mean large DOF.
4) METERING
Metering mode also known as 'Camera Metering', 'Exposure Metering'. It is very important to know how metering works and what each of the metering mode does is important in photography, because it helps photographers control their exposure with minimum effort and take better pictures in unusual lighting situations.
What is Metering? Metering is how your camera determines what the correct shutter speed and aperture should be, depending on the amount of light that goes into camera and the sensitivity of the sensor. Nowadays, every DSLR has an integrated light meter that automatically measures that reflected light and determines the optimal exposure. The most common metering modes in digital cameras today are :
a) Matrix Metering (Nikon), also known as Evaluate Metering (Canon)
b) Center-weighted Metering
c) Spot Metering (Nikon), also known as Partial Metering (Canon)
In addition, you can see the camera meter in action when you shoot in Manual Mode, which you look inside the viewfinder and you will see bars going left or right, with a zero in the middle, as illustrated below.
p/s: If you want to change shutter speed, you will need to change one or both of the other elements. (ISO or Aperture). For examples if you speed up your shutter speed one stop (from 1/125 to 1/250) you are effectively letting half as much light into your camera. To compensate for this you will probably need to increase your aperture one stop (for example from f16 to f11). The other alternatives would be to choose a faster ISO rating (for example ISO 100 to ISO 400).
DEPTH OF FIELD (DOF) is the amount of your shot that will be in focus. Large depth of field means that most of your image will be in focus whether it is close to your camera or far away. Aperture has a big impact upon DOF. Large aperture ( it is a smaller number) will decrease DOF while small aperture ( large number ) will give you larger DOF. Small number mean small DOF and large number mean large DOF.
Metering mode also known as 'Camera Metering', 'Exposure Metering'. It is very important to know how metering works and what each of the metering mode does is important in photography, because it helps photographers control their exposure with minimum effort and take better pictures in unusual lighting situations.
What is Metering? Metering is how your camera determines what the correct shutter speed and aperture should be, depending on the amount of light that goes into camera and the sensitivity of the sensor. Nowadays, every DSLR has an integrated light meter that automatically measures that reflected light and determines the optimal exposure. The most common metering modes in digital cameras today are :
a) Matrix Metering (Nikon), also known as Evaluate Metering (Canon)
b) Center-weighted Metering
c) Spot Metering (Nikon), also known as Partial Metering (Canon)
If you at a very bright area, the bars will go to '+' side while if you at a very dark area, the bars will go to the '-' side. Beside that, you would need to increase or decrease your shutter speed to get to 'o', which is the optimal exposure, according to your camera meter.
a) Matrix Meeting.
Matrix meeting is the default metering mode on most DSLR. It works similarly to the above example by dividing the entire frame into multiple 'zones', which are then all analyzed on individual basis for light and dark tones. One of the key factors that affects matrix metering, is where the camera focus point is set to. After reading information from all individuals zones, the metering system look at where you focused within the frame and marks it more important than all other zones.
b) Center-Weighted Metering
Evaluate the light in the middle of the frame and its surroundings and ignores the corners. Center-weighted metering does not look at the focus point you select and only evaluates the middle area of the image.
Use this mode when you want the camera to prioritize the middle of the frame, which works great for close-up portraits and relatively large subjects that are in the middle of the frame. For example, if you were taking a headshot of a person with the sun behind him/her, then this mode would expose the face of the person correctly, even though everything else would probably get heavily overexposed.
c) Spot Metering
Only evaluates the light around your focus point and ignores everything else. It evaluates a single zone/cell and calculate exposure based on that single area, nothing else. When your subjects do not take much of the space, using Matrix or Center weighted metering modes would most likely result in a silhouette, if the subject was back-lit. Spot metering works great for back-lit subjects like that.
For examples using spot metering when photographing in the moon. Because the moon would take up small portion of the frame and the sky is completely dark around it, it is best to use spot metering.
p/s: If you want to change shutter speed, you will need to change one or both of the other elements. (ISO or Aperture). For examples if you speed up your shutter speed one stop (from 1/125 to 1/250) you are effectively letting half as much light into your camera. To compensate for this you will probably need to increase your aperture one stop (for example from f16 to f11). The other alternatives would be to choose a faster ISO rating (for example ISO 100 to ISO 400).
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- References :
http://www.digital-photography-school.com/aperture
http://www.digital-photography-school.com/shutter-speed
http://www.digital-photography-school.com/iso-settings
http://mansurovs.com/
http://www.digital-photography-school.com/aperture
http://www.digital-photography-school.com/shutter-speed
http://www.digital-photography-school.com/iso-settings
http://mansurovs.com/
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