User Guide

If dust particles are found on the sensor, this is classified as a manufacturing error of the module, and the
camera should be replaced. Any particles inside the cavity between the protection window and the lens have
most probably been trapped there in the assembly phase at a Nokia factory. Unauthorized disassembling of
the product can also be the root of the problem. However, in most cases it should be possible to remove the
particle(s) by using clean compressed air. Never wipe the lens surface before trying compressed air; the
possibility of damaging the lens is substantial. Always check the image sharpness after removing dust.
Testing camera image sharpness
Symptoms and diagnosis
If pictures taken with a device are claimed to be blurry, there are six possible sources for the problem:
1 The protection window is fingerprinted, soiled, dirty, visibly scratched or broken.
2 The photographed object is too close – the camera lens operates with distances from 64 cm to infinity.
This is no cause to replace camera module.
3 User has tried to take pictures in too dark conditions, and images are blurred due to handshake or
movement. This is no cause to replace camera module.
4 There is dirt between the protection window and camera lens.
5 The protection window is defective. This can be either a manufacturing failure or caused by the user. The
window should be changed.
6 The camera lens is misfocused because of a manufacturing error.
A quantitative analysis of sharpness is very difficult to conduct in any other environment than optics
laboratory. Therefore, subjective analysis should be used.
If no visible defects (items 1-4) are found, a couple of test images should be taken. Generally, a well-
illuminated typical indoor scene can be used as a target. The main considerations are:
• The protection window has to be clean.
• The amount of light (300 – 600 lux (bright office lighting)) is sufficient.
• The scene should contain, for example, small objects for checking sharpness. Their distance should be 1
– 2 meters.
• If possible, compare the image to another image of the same scene, taken with a different device. Note
that the reference device has to be a similar Nokia phone.
Steps
1. Take several images of small objects in the distance of 1-2 metres.
2. Analyse the images on a PC screen at 100% scaling with the reference images.
Pay attention to the computer display settings: at least 65000 colors (16-bit) have to be used. True colour
(24-bit, 16 million colours) or 32-bit (full colour) setting is recommended.
Next actions
If there appears to be a clearly noticeable difference between the reference image and the test images, the
module might have a misfocused lens -> change the module.
Re-check the resolution after changing the camera module.
If the changed module produces the same result, the fault is probably in the camera window. Check the
window by looking carefully through it when replacing the module.
Dirty camera lens protection window
The following series of images demonstrates the effects of fingerprints on the camera protection window.
RM-170; RM-171
Camera Module Troubleshooting Nokia Customer Care
Issue 1 COMPANY CONFIDENTIAL Page 8 –13
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