Nokia RM-12 Troubleshooting Instructions page 75

RM-12
Sharpness: good quality images are 'sharp' or 'crisp', meaning that image details are well vis-
ible 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 per-
formance.
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. changing the
camera module.
1 Distance to target: the lens in the module is specified to operate satisfactorily
from 40 cm 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 40 cm. Lack of sharpness will be first visible in full reso-
lution (1152 x 864) 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.
2 Amount of light available: in dim conditions camera runs out of sensitivity. Expo-
sure time is long (especially in night mode) and the risk of getting shaken (=
blurred) images grows. Image noise level grows. The maximum exposure time in
night mode is ¼ seconds, so images need to be taken with extreme care and by
supporting the phone when the amount of light reflected from the target is low.
Due to longer exposure time and larger gain value noise level is increasing under
low light conditions. Sometimes blurring may even happen at daytime if image is
taken very carelessly. See Handshake has caused blurring of this image for exam-
Page 73
Figure 1: Image blurred due to too close distance to target
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Issue 1 11/2004