The Effect Of Image Taking Conditions On Image Quality - Nokia n80 User Manual

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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.
Distance to target
The lens in the module is specified to operate satisfactorily from 68 cm to infinite distance of scene objects
in hyper-focal position, and 17.5 to 23.4 in the macro mode.
To use the camera in hyper-focal mode, the macro mode switch situated in the camera bezel beneath the
camera window must be locked into the right hand position indicated by the mountain icon. To use the
macro mode, the switch must be locked in the left hand position indicated by the tulip (macro) icon. If the
switch is not locked in hyper-focal or macro position and set to an intermediate center position, the sharpness
of the image will be degraded. In practice, the operation is such that close objects may be noticed to get
more blurred when distance to them is shortened from 48 cm. Lack of sharpness is first visible in full resolution
(2048 * 1536) images. If observing just the viewfinder, even very close objects may seem to appear sharp.
This is normal; do not change 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 night mode increases, 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.
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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 67 Blurred image. Target too close.
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Camera Module Troubleshooting
Issue 1