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Master the Automatic Exposure (AE)


In the beginning when we learn how to photograph it is the most automatic mode which is used. But many find that the more they shoot, the more control they want in the end result. Then it's time to start looking at the different exposure methods. P (Program AE), A (Aperture Priority AE), AV (Aperture Value), S (Shutter Priority AE), TV (Time Value) and M (Manual).


The position Automatic Mode is useful. The camera takes care of most non-point and shoot. Automatic mode determines whether and when to use a flash, the size of the image files and the color tone of the photographs.

Comfortable But Restrictive.


Apart from that you may want to choose whether to use flash or not, your images become more like you want them if you set the exposure, there upon what combination of shutter speed and aperture to be used for each image.

A fast shutter speed allows more frozen movements and reduces the risk of camera shake. A slow shutter speed can make nice effects like soft water, and long tracks from car lights.

Aperture mainly affect the final result by the depth of field is changing. A small aperture (high number) gives a large area of sharpness in depth, a small aperture is better if you want the foreground or background out of focus.

With a given ISO numbers (light sensitivity) set on the camera and a given motive, there are many combinations of shutter speed and aperture, which all give an accurate exposure, Thus an image that is neither too light or too dark. All the combinations have different shutter speeds and different aperture, and which one is best depends on how you want the image to be.

All modern SLRs have four basis modes for selecting the right combination.


P stands for Program AE, which indicate that the camera automatically selects both shutter speed and aperture. Thus, the same as auto setting, except that the camera does not take control of flash and other settings.

A or Av ("Aperture Priority AE" or "Aperture Value") means that the aperture is automatically controlled and allows photographers to lock the aperture and the camera adjusts the exposure using only the shutter speed.

S or Tv ("Shutter Priority AE" or "Time Value") means that the photographer select a desired shutter speed and the camera automatically sets the most appropriate aperture to match.

M stands for Manual Exposure, which means that automation is disconnected completely. The photographer chooses both shutter speed and aperture.


P - Program AE


P is best:
  • When you are comfortable with your photography.
  • When it is stressful and you do not photograph with the spinal cord.
  • When you have a zoom lens with high zoom ratio P can be particularly useful approach because most cameras adjust the shutter speed to the focal length (the longer the focal length, the shorter the shutter speed to avoid camera shake).

P is bad:
  • When taking pictures with a flash. At that moment the P setting, often gives a very dominant light from the flash. That's because the camera is programmed to use a relatively small aperture and a relatively fast shutter speed (usually 1/60 second) for sharp images. The result is typical party pictures in a negative sense — strong flashlight and a dark background.

More about the P mode:
On most cameras, the conscious photographer temporarily select an alternative combination of shutter speed and aperture by rotating the input knob. It is called Program Shift. Usually the Program Shift is reset after a while.


A/AV - Aperture Priority AE


A/AV is best:
  • When you want maximum depth of field. Select the smallest aperture (highest number). The shutter speed can be long, perhaps you may need a tripod.
  • When you want to have minimal depth of field. Choose the largest aperture (lowest rate). In photography language this is called "full aperture".
  • When you want to have the shortest possible shutter "full opening" is the way to go.
  • When you want to sharpest picture possible. Most lenses are best suited for aperture approximately f/5.6 (bright fixed focal lengths), f/8 (bright zoom) or f/11 (dim zooms). This is a rough guideline.

A/AV is bad:
  • When you want the exact shutter speed.


S/TV - Selects the Shutter By Itself


S/TV is best:
  • When you want an accurate shutter to pan or freeze a motion. Panning is when you follow a moving object with the camera and want the background to be blurred. The shutter speed adjusts to the speed of the object.
  • For flash photography when you want to have a lot of ambient light and "freeze" the moment closest to the camera while there is movement or camera shake in the background. Very common in so-called "mingle photography". If the environment is dark, choose a fairly high ISO number, around 400-800.
  • To avoid the stripes on the television and computer screens (the old thick type). Set the shutter speed to 1/25 seconds.
  • At all other times when you want an exact shutter speed.

S/TV is bad:
  • When you want the shortest possible shutter speed. Use the A/AV and set the maximum aperture.


M - Manual Exposure


M is best:
  • When you want full control and awareness.
  • When you want a series of images to be consistently exposed, and so, equally bright.

M is bad:
  • When it is stressful, unless you are very used to it.

More about the M mode:
If you know you want to use manual exposure often, it might be an idea to buy a camera with separate input knobs for shutter speed and aperture.


What Shutter at What Occasion?


To get maximum advantage of the different types of automation a little basic knowledge of shutter speeds is required.

1/8000 second.Almost freezes a golf swing.
1/500 second.Most movements in handball, football and ice hockey are frozen.
1/60 second.Works well for images with stationary objects, a sudden gesture of the picture can become blurred.
1/30 second.Now the shutter speed is so long that it is difficult to keep the camera steady by hand. But with the camera on a tripod, you can still take great portraits.
1/8 second.Now we are into really slow shutter speeds. Try this in S/TV mode with flash at your next party. Becomes a bit unusual, but interesting pictures.
1 second.Impossible to keep the camera steady without a tripod, but you get nice bright trace of headlights and sparklers.