Nikon D40 - Manual (Page 117)

Technical Notes/Caring for the Camera 105
The Low-Pass Filter
The image sensor that acts as the camera’s picture element is fitted with a low-pass filter to
prevent moiré. If you suspect that dirt or dust on the filter is appearing in photographs, you
can clean the filter 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. To prevent the camera from powering off while the mirror is raised, use a
full-charged battery or an optional EH-5 AC adapter and EP-5 AC adapter connector ( 103).
Use a Reliable Power Source
The shutter curtain is delicate and easily damaged. If the camera turns off with the mirror raised, the
curtain will close automatically. To prevent damage to the curtain, observe the following precautions:
• Do not turn the camera off until cleaning or inspection is complete. Do not remove or disconnect
the power source while the mirror is raised.
• If the battery runs low while the mirror is raised, a beep will sound and the AF-assist illuminator will
blink to warn that the shutter curtain will close and the mirror will be lowered after about two min-
utes. End cleaning or inspection immediately.
1 Remove the lens and turn the camera on.
2 Select Mirror lock-up from the setup menu (note that this option is not available at
battery levels of
or below).
3 Highlight On and press OK. The message shown at right will
be displayed. To restore normal operation without inspecting
the low-pass filter, turn the camera off.
4 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.
5 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 7.
6 Remove any dust and lint from the filter with a blower. Do not
use a blower-brush, as the bristles could damage the filter.
Dirt that can not be removed with a blower can only be
removed by Nikon-authorized service personnel. Under no
circumstances should you touch or wipe the filter.
7 Turn the camera off. The mirror will be lowered and the shutter curtain will close.
Replace the lens or body cap.