The Effect Of Image Taking Conditions On Image Quality - Nokia RM-779 Service Manual

Sharpness

The effect of image taking conditions on image quality

There are some factors, which may cause poor image quality, if not taken into account by the end user when
shooting images, and thus may result in complaints. The items listed are normal to camera operation and
are not a reason for changing the camera module.
The amount of light available
In dim conditions camera runs out of sensitivity. The exposure time is long (especially in the night mode)
and the risk of getting shaken (= blurred) images increases. In addition, image noise level grows. The
maximum exposure time in the night mode is ¼ seconds. Therefore, images need to be taken with extreme
care and by supporting the phone when the amount of light reflected from the target is low. Because of the
longer exposure time and larger gain value, noise level increases in low light conditions. Sometimes blurring
may even occur in daytime, if the image is taken very carelessly. See the figure below for an example. This
is normal; do not change the camera module.
Movement in bright light
If an image is taken of moving objects or if the device is used in a moving vehicle, object 'skewing' or 'tilting'
may occur. This phenomenon is fundamental to most CMOS camera types, and may happen when using the
electronic shutter. The movement of camera or object sometimes cause blurring indoors or in dim lighting
conditions because of long exposure time. This is normal; do not change the camera module.
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Good quality images are 'sharp' or 'crisp', meaning that image details are
well visible in the picture. However, certain issues, such as non-idealities
in optics, cause image blurring, making objects in picture to appear 'soft'.
Each camera type typically has its own level of performance.
Figure 29 Blurring caused by shaking hands
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Camera Module Troubleshooting
RM-779
Issue 1