Types of Camera Modes
Here are the four main types of camera modes that can be found in most digital cameras today:
- Program (P)
- Shutter Priority (Tv) or (S)
- Aperture Priority (Av) or (A)
- Manual (M)
In
“Program” mode, the camera automatically chooses the Aperture and the
Shutter Speed for you, based on the amount of light that passes through
the lens. This is the mode you want to use for “point and shoot”
moments, when you just need to quickly snap a picture. The camera will
try to balance between aperture and shutter speed, increasing and
decreasing the two based on the intensity of light. If you point the
camera to a bright area, the aperture will automatically increase to a
bigger number, while keeping the shutter speed reasonably fast. Pointing
the camera to a darker area will decrease the aperture to a lower
number, in order to maintain a reasonably fast shutter speed. If there
is not enough light, the lens aperture will stay at the lowest number
(maximum aperture), while the shutter speed will keep on decreasing
until it reaches proper exposure.
I personally never use this
mode, since it does not give me much control over the exposure. There is
a way to override the camera-guessed shutter speed and aperture by
moving the control dial (on Nikon cameras it is the dial on the back of
the camera). If you rotate the control dial towards the left, the camera
will decrease the shutter speed and increase the aperture. If you
rotate the dial towards the right, the camera will increase the shutter
speed and decrease the aperture. Basically, if you needed to get a
faster shutter speed for freezing action, you would rotate the dial to
the right, and if you needed to get a large
depth of field, you would rotate the dial to the left.
In
“Shutter Priority” mode, you manually set the camera’s shutter speed
and the camera automatically picks the right aperture for you, based on
the amount of light that passes through the lens. This mode is intended
to be used when motion needs to be frozen or intentionally blurred. If
there is too much light, the camera will increase the lens aperture to a
higher number, which decreases the amount of light that passes through
the lens. If there is not enough light, the camera will decrease the
aperture to the lowest number, so that more light passes through the
lens. So in Shutter Priority mode, the shutter speed stays the same
(what you set it to), while aperture automatically increases and
decreases, based on the amount of light. In addition, there is no
control over subject isolation, because you are letting the camera
control the
depth of field.
I
try not to use this mode either, because there is a risk of getting an
overexposed or underexposed image. Why? Because if the amount of ambient
light is not sufficient and I set the shutter speed to a really high
number, my exposure will be limited to the aperture/speed of my lens.
For example, if the maximum aperture of my lens is f/4.0, the camera
will not be able to use a lower aperture than f/4.0 and will still shoot
at the fast shutter speed that I manually set. The result will be an
underexposed image. At the same time, if I use a very slow shutter speed
when there is plenty of light, the image will be overexposed and blown
out.
In
“Aperture Priority” mode, you manually set the lens aperture, while the
camera automatically picks the right shutter speed to properly expose
the image. You have full control over subject isolation and you can play
with the
depth of field,
because you can increase or decrease the lens aperture and let the
camera do the math on measuring the right shutter speed. If there is too
much light, the camera will automatically increase the shutter speed,
while if you are in a low-light environment, the camera will decrease
the shutter speed. There is almost no risk of having an overexposed or
an underexposed image, because the shutter speed can go as low as 30
seconds and as fast as 1/4000-1/8000th of a second (depending on the
camera), which is more than sufficient for most lighting situations.
This
is the mode that I use 95% of the time, because I have full control
over the depth of field and I know that the image will be properly
exposed under normal circumstances. The metering systems in most modern
cameras work very well and I let the camera calculate and control the
shutter speed for me.
As
the name suggests, “Manual” mode stands for a full manual control of
Aperture and Shutter Speed. In this mode, you can manually set both the
aperture and the shutter speed to any value you want – the camera lets
you fully take over the exposure controls. This mode is generally used
in situations, where the camera has a hard time figuring out the correct
exposure in extreme lighting situations. For example, if you are
photographing a scene with a very bright area, the camera might
incorrectly guess the exposure and either overexpose or underexpose the
rest of the image. In those cases, you can set your camera to manual
mode, then evaluate the amount of light in darker and brighter areas and
override the exposure with your own settings. Manual mode is also
useful for consistency, if you need to make sure that both shutter speed
and aperture stay the same across multiple exposures. For example, to
properly stitch a panorama, all shots that you are trying to put
together need to have the same shutter speed and aperture. Otherwise,
some images will be darker, while others are lighter. Once you set the
shutter speed and aperture to the values of your choice in manual mode,
your images will all have consistent exposures.
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