Canon EOS 250D Advanced User's Manual page 275

Dust Delete Data
After the Dust Delete Data is obtained, it is appended to all the JPEG
and RAW images captured thereafter. Before an important shoot, it is
recommended that you update the Dust Delete Data by obtaining it again.
For details about using Digital Photo Professional (EOS software) to erase
dust spots automatically, refer to the Digital Photo Professional Instruction
Manual.
The Dust Delete Data appended to the image is so small that it hardly
affects the image file size.
Be sure to use a solid-white object such as a new sheet of white paper. If the
z
object has any pattern or design, it may be recognized as dust data and affect
the accuracy of the dust deletion with EOS software.
3
Shoot a solid-white object.
At a distance of 20 cm–30 cm
z
(0.7 ft.–1.0 ft.), fill the viewfinder with a
patternless, solid-white object and take
a picture.
The picture will be taken in aperture-
B
priority AE mode at an aperture of f/22.
Since the image will not be saved, the
z
data can still be obtained even if there is
no card in the camera.
When the picture is taken, the camera
B
will start collecting the Dust Delete Data.
When the Dust Delete Data is obtained,
a message will appear.
Select [OK] and the menu will reappear.
If the data is not obtained successfully,
z
an error message will appear. After
reviewing the information in Preparation
(= 274), select [OK], then shoot
again.
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