That would be my suspicion as well. A fellow that was using the
camera removed the lens to change it and blew into the opening so
perhaps????
Any marks seen in images have to be from smears or dust or whatever
ON the sensor (well, OK then, on the glass cover attached directly to
the sensor)
There is never, ever, any way dust or smears on the lens or the
protective glass filter just inside the lens mounting can ever be
shown in images. So it's simply a case of cleaning the sensor
(=glass ontopof).
I have also found that it definitely pays to fit the end of a vacuum
cleaner's hose with (well, I used) an empty ballpoint pen casing -I
made a plug to fit inside the hose, with the pen casing in the
middle. This provides a small tube to increase the suction that can
be directed as required inside the camera body - at the end of any
cleaning. I have marked my tube with some tape so that I know how
far it can go inside without actually touching the sensor surface.
In cleaning, I use a couple of 12mm nylon soft artists brushes. Both
cleaned after each use (and obviously before the very first use) by a
drop of washing up liquid in a saucer of warm water, swirl about and
then after, rinse three times, then shake well and hang to thoroughly
dry. Then store in plastic bag before next use.
First is used to brush inside the opening, with filter removed. Then
a quick vacuum - avoding (including avoiding the brush) touching the
focus screen. Then camera opened for cleaning, per manual
destructions. Then quick brush inside - flicking the brush on a bit
of stout card between each brushing to flick away dust.
Then sensor cleaned (whichever way preferred) and a vacuum. Then a
final brush with the other brush - used only on the sensor - then
another vacuum then closed. Quick vacuum inside chamber again and
(having already cleaned the filter and placed on clean surface) brush
with the sensor brush and filter replaced.
I charge the brush this way. Either flick rapidly across piece of
stout card (never use plastic as that discharges the static) to build
up static in the nylon brush hairs. I actually use a battery
operated coffee frother - this has body for 2 x AA batteries, with
stout wire about 4-5" long and a small wire coil on its end - into
which the cut-down handle of the 2nd brush can be fitted and wedged.
Turn on the switch and within a couple of seconds, the nylon is fully
charged with static, to attract the dust. It's a do-it-yourself
"Arctic Butterfly" for about a £1/$1.50.
Hope that gives some inspiration. Vacuuming gets rid of any dust
that otherwise will be back on the sensor very quickly - if not
sooner!
--
Zone8
The photograph isolates and perpetuates a moment of time: an
important and revealing moment, or an unimportant and meaningless
one, depending upon the photographer's understanding of his subject
and mastery of his process. -Edward Weston
http://www.photosnowdonia.co.uk/ZPS
