Sensor noise: The characteristic
that most limits the overall tonal range of a digital camera is noise in the sensor array.
Without getting overly technical, a noisy sensor means you'll see "grain" or
"snow" in solid grays or colors. This effect is particularly pronounced in
shadow areas.
Sensor noise usually appears as "snow" in the image, much as you would see on a
television set experiencing poor reception. Depending on the construction of the camera
system, the noise may appear as randomly distributed monochrome or colored flecks.
(Certain sensor irregularities may result in some patterning to the noise flecks, but
usually the distribution will be fairly random.)
In DPS cameras, noise effects are largely masked by the JPEG image-compression process.
Noise is nonetheless a primary limitation, even if we don't see the effects directly.
Integration techniques average successive images together minus the average thermal noise
in hopes of averaging out the random noise and one of the thermal additive noise. This
technique is marginally successful since individual pixels vary in the amount of thermal
noise that is generated, resulting in half of the pixels containing thermal noise and the
other half having subtracted off of the signal that you are trying to acquire. This extra
mathematics requires extra time by the computer extends the exposure and delays the image
to the screen.
Shutter: The shutter opens and closes very rapidly to control the amount of light
passing through the aperture. Some cameras allow this timing to be manually adjusted. Like
shutters on your window, you can only see outside as long as the shutter is open.
Shutter Priority: Slow the shutter in dim lit or night settings to capture more
natural light (8/1 = Shutter Open 8 Seconds, 4/1 = Shutter Open 4 Seconds) and the
resulting image will appear brighter. Keeping the shutter open longer may cause movement
to blur, so it is best to keep the camera on a stable tripod. An example of this blur is
the long red glow of taillights on a freeway at night. Speed the shutter in bright
settings to freeze the action of fast moving objects (1/1000 = Shutter Open 1/1000 of a
Second). An example of fast shutter action is the ability to see individual spokes on a
bicycle that was racing past. During Shutter Priority Mode on Toshiba Digital Cameras the
Aperture is automatically set and the Flash is disabled to optimize performance.
BULB Photography: This term refers to a standard setting for slow shutter control.
This is a special setting for low light situations, similar to the Shutter Priority Mode.
Timing for the shutter is set in the Menu options. The shutter remains open for a longer
period of time and the Flash is disabled to capture more of the natural light. Although
this is effective, it is not as sophisticated or precise as Shutter Priority.
AE: Auto Exposure is a system for automatically setting exposure by choosing a
shutter speed and aperture value according to the current light conditions. This is
commonly referred to as "Auto Mode", and is the best settings for most
conditions. It enables the photographer to concentrate on the subject while the camera
adapts to optimum performance for the environment.
Serial output: An outgoing connector compatible with virtually all PCs and beige
(pre-iMac) Macintoshes, making serial connections the most universal of transfer formats.
However, it's much slower than USB.
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