Image Taking Conditions Effect To Image Quality - Nokia NHL-2NA Series Troubleshooting Instructions

NHL-2NA
Resolution: Usually the amount of pixels in the camera sensor, e.g. VGA means 640 x
480 pixels. In some occasions the term resolution is used for describing the sharpness of
the images.
Sensitivity: camera module's sensitivity to light. In equivalent illumination conditions, a
less sensitive camera needs longer exposure time to gather enough light for forming a
good image. Analogous to ISO speed in photographic film.
Sharpness: camera's images are ideally 'sharp' or 'crisp', meaning that image details are
well visible in the picture. However, certain issues like non-idealities in optics, cause
image blurring, making objects in picture to appear 'soft'. Each camera type typically has
it's own level of performance.

Image taking conditions effect to image quality

This chapter lists some of the factors, which may cause poor image quality if not taken
into account by end user when shooting pictures, and thus may result in complaints. The
listed items are normal to camera operation and do not cause a need for e.g. chang-
ing the camera module.
Distance to target: the lens in the module is specified to operate satisfactorily from
30cm to infinite distance of scene objects. In practice, the operation is such that close
objects may be noticed to get more blurred when distance to them is shortened from
40cm. Lack of sharpness will be first visible in full resolution (VGA) images. If observing
just the viewfinder, even very close objects may seem to appear sharp. This is normal
behavior, do not change the camera module.
Figure 1: Image blurred due to too close distance to target (5 cm)
Sharpness of picture edges: lens performance degrades in image edges, and generally the
image is sharpest in center part. Particularly this applies to distant objects (> 1 meter).
With near objects (about 5 cm – 30 cm) the lens behaves so that center of the image
may not be the sharpest point, instead maximum sharpness is approximately in half way
from center to edges. This phenomena can particularly be seen in images which have
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