On 22 Nov 1998 14:06:12 GMT, fstopman@aol.com (Fstopman) wrote:

>When I use compressed air, I hold the tube about 12" away from the camera, so
>that the air velocity in the mirror box is low (similar to a bulb). If you are
>careful, compressed air is OK.

This can blow dust up on top of the screen, though, making it
inaccessible without a repair unless the viewing screen is
user-removeable... I generally recommend using great care when
the lens is off (and avoiding changing lenses in windy conditions,
or at least facing the body opening downward while it is
[briefly!] open...) as a preventive. BTW, if the screen is
a mess with dust, even with the above reservation, I would
try a very gentle squirt with a hand-bulb (brush-less)
blower, since it is more likely to improve things than to
worsen them. Also, if there is a smudge on the mirror, it
can often be removed without damage if one breaths *up* onto
its surface to fog it, and clears the fog with VERY LIGHT
wiping with CLEAN cotton swabs (using one only briefly before
replacing it!). As others have pointed out (unless the viewing
screen is user-removeable - or, better yet, the prism top
is also removeable [one of the great advantages of Nikon's
pro line, and some others...], dust is best left in place,
alas...