Nikon D5100 Reference Manual page 58

IN Manual Cleaning
If foreign matter can not be removed from the low-pass filter using the Clean image
sensor option in the setup menu (_ 210), the filter can be cleaned manually as
described below. Note, however, that the filter is extremely delicate and easily
damaged. Nikon recommends that the filter be cleaned only by Nikon-authorized
service personnel.
2
Charge the battery or connect an AC adapter.
A reliable power source is required when inspecting or cleaning the low-pass
filter. Turn the camera off and insert a fully-charged EN-EL14 battery or connect
an optional EP-SA power connector and EH-Sb AC adapter.
Remove the lens.
Turn the camera off and remove the lens.
3
Select Lock mirror up for cleaning. __
Turn the camera on and press the MENU
button to display the menus. Highlight Lock
mirror up for cleaning in the setup menu
and press I_ (note that this option is not
available at battery levels of _ or below). MENU b utton
4
Press _).
The message shown at right will be displayed in the
monitor. To restore normal operation without inspecting
the low-pass filter, turn the camera off.
5
6
Raise the mirror.
Press the shutter-release button all the way down. The
mirror will be raised and the shutter curtain will open,
revealing the low-pass filter.
%
Examine the low-pass filter.
Holding the camera so that light falls on the low-pass filter,
examine the filter for dust or lint. If no foreign objects are
present, proceed to Step 8.
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