Sunday, 27 September, 2015 15:03
CLEANING OF SENSORS
very first thing to state - and to make very clear as many who should
know better often mention this is a cause - is any dust on the lens,
filter if fitted, mirror or focusing screen will NEVER show as dust
spots on the sensor. It is impossible for them to be focussed on to
the sensor. Only one lens (Nikon 7.5mm f/5.6 Fish-eye-NIKKOR - 1966-1970)
had a large curved front element that was capable of focusing anything
on it. In those days, not many were made as so expensive and one company
that hired this out (London based, at the time, Pelling and Cross)
only did so WITH an operative because any marks on the front element
would ruin the lens for that very reason.
The best and
simplest way to effect removal of any loose debris, should it prove
necessary, is described below. For how to check what is on your sensor
cover glass (normally also an AA - anti-aliasing - filter), proceed
as follows: Set camera for exposure on sky to Infinity focus, on mid-zoom
(say 50mm) and aperture f22 or even f16 to really show up if anything
is there. Expose so it is reasonably light - the speed of shutter
does not have to stop any camera shake of course so even something
like 1/30th should be fine or even 1/15th. The smaller f-stop (aperture)
is necessary to really project a narrower beam of light towards the
sensor so any dust on its cover glass will be more-or-less focussed
sharply due its "sharper" projected shadow. One tip, whenever
possible, is to use wider apertures like say f8 or even f5.6 (if sharpness
and Depth of Field requirements are met as desired) as they will not
often even show up any dust spots. Well worth remembering, especially
if plainer light areas like skies are being photographed, as such
parts will show up dust spots more easily.
procedure, if necessary, follows)
Here's a link
to an early pbase illustrated article for the Sigma DSLRs by (mainly)
Laurence Matson BUT only use as a basic guide on procedures. Always
refer to the camera manual to ensure compliance with "how"
to set camera for cleaning - with especial emphasis on either using
a mains power supply (if available) or at least ensuring any batteries
are fully charged - if the camera shutter should close and mirror
drop during cleaning, it could of course cause a lot of physical damage
to those parts if you are in the process of using brushes, etc. inside
(BUT I have my own variation on any wet cleaning as detailed below
- so only use this as way of seeing some photos)
I proceed for simple removal of any loose debris as follows:
1) Get to an
art supply shop and purchase a simple nylon brush (MUST be nylon so
can be given a static charge to attract dust). The one I have is labelled:
12 Lotus Deco 8431 pèbèo SRILANKA and the built-on bar
code on end tip has: 3167860013339 (It is about ½" wide
and approx, say 1/8" thick as a guide for recognition in a rack).
The brush is about 7"-8" overall length.
2) For the Sigma DSLRs only, you need a small instrument-set type
cross-head screwdriver - very small to fit the small screw that holds
the body-insert-glass-filter in place just inside the body where lens
fits. A small bit of BluTac will prove useful to fit on end of that
screwdriver to hold screw for when removing and replacing.
3) Another slightly bigger piece of BluTac is also useful for removing/replacing
the glass filter (say about ½" ball flattened slightly
so can push on end of filter for when replacing).
4) You need a decent blower without the brush bit - only need a blower.
As alternative a washed and dried fairly-rigid type plastic bottle
(like say once held washing up liquid) can become a blower but must
have been well washed out and thoroughly dried of course. Stiff plastic
construction necessary to recover quickly after each squeeze.
5) Ideally, to ensure blown dust is removed and not just displaced,
you will need a vacuum cleaner with hose and some card or whatever
taped around end to make a smaller tapered nozzle say about 1"
diameter so can at least get slightly into the body but not enough
to touch sensor or mirror.
6) Have the power supply (if one is available) ready to plug in -
on the Sigma DSLRs is the socket is under a large rubber cover on
left side as seen from back of camera. Will need adapter for your
country's sockets if a different one is fitted of course - or change
1) Have piece
of clean A4 paper on desk. Ensure camera carrying strap is out of
the way when working.
2) Remove lens
and put aside, face down with front cap on.
3) (For the Sigma DSLRs) Remove little screw to release the cover-filter
inside body and as should have small BluTac on end, that will help
removal and place screw safely to one side to ensure cannot get lost
- use a saucer or something. Use the blob of BluTac on end of filter
frame, move slightly down to free from its top slots and put aside
on the paper. Note how it fits at top when removing as will help when
locating on replacement.
4) Now hold the camera upside down and use the blower to dislodge
any loose dust - and then vacuum at the opening - repeat a couple
of times. Do NOT use the brush on either focus screen or the mirror.
Leave those untouched - only blower and vacuum to be used. Both mirror
and focus screen can be both easily and permanently abraded so leave
well alone! Any attached debris should be left as cannot cause spots
on the image. If dust seen in the viewfinder - put up with it - better
than seeing a badly scratched screen due damaging attempts to clean!
It is very soft plastic construction.
5) If available - Plug in the power supply into power socket on wall
and on camera. If not, ensure batteries are fully charged!
6) For Sigma DSLRs, Turn left wheel to AB last setting. Hold down
RES and +/- buttons at top on back of camera until the mirror goes
up and shutter opens - usually about 3 second or so holding-down to
do this. For other cameras, use the procedure shown in the camera
7) Hold camera upside down and give a few good blows inside to dislodge
any debris. Then flick the brush rapidly up/down or to/fro on something
non-static (like clean piece of card that cannot shed debris - say
even piece of magazine glossy page folded to make rigid for this purpose
- not anything plastic that can hold a static charge as that will
simply dissipate any charge from the nylon bristles as they are charged)
- will need about 20 to 30 rapid flicks to/fro complete to charge.
(You can easily check if charged by having a small piece of paper,
say about ¼" square-ish and see, after flicking nylon
bristles, if it can be picked up by the bristles). Then wipe the sensor
once side to side. Try and keep camera as far as possible upside down
or tilted as much as practical so you can see what you are doing.
Repeat nylon bristles charging and brush again, this time in opposite
direction. Only ever brush the sensor cover glass - never inside the
camera as that could attract any oil particles or whatever to bristles
and then to cover glass. Often debris can be generated from the shutter
mechanism itself. Another regular cause of dust inside camera bodies
is the use of push/pull zoom lenses - which can, in effect, suck air
with dust inside. Obviously, try and use such zooms slowly to at least
minimise the problems.
8) Then re-blow and then vacuum, with camera upside down. If you make
the slight card funnel (make sure card is shiny and cannot give off
its own debris!) so it cannot go inside enough to touch anything (in
reality it only needs to be in the entrance slightly) then that will
suck out anything loose. Wiggle slightly to change angle to cause
interior turbulence. Repeat the blower a couple of times with vacuuming
each time. Is actually quite quick to complete. Ideally - make sure
the vacuum body is away from the working area so any emitted dust
will not find its way inside the camera. Only needs about ten seconds
9) When finished, with camera upside down on the paper (make sure
any dust is swept off with side of hand) for Sigma DSLRs return the
left dial back to the OFF position to close the shutter - or do what's
required for other makes - and return mirror to working position.
Blow once inside and do quick vacuum to finish. Unplug the power lead
from camera if used.
10) For Sigma DSLRs, blow the cover glass both sides - turn camera
up and replace the glass. The BluTac blob on end where screw hole
is helps with positioning. Fitting it back is a little fiddly - it
has to fit at top over larger flat central piece and under the (on
sides) smaller flat pieces. You will know when it is properly located
(wants to go under the wider flat central piece but don't let it!)
and then you can replace the screw (the little BluTac enables screwdriver
to hold small screw on end for easy relocation).
11) Again, for Sigma DSLRs, give cover filter glass final quick blow
with camera upside down and replace lens - blow that as well!
sounds a lot but is fairly quick to do if you prepare properly and
the vacuuming seems, my experience and idea, to be essential for success
- and I DO MEAN ESSENTIAL TO VACUUM for getting loose dust out of
the camera body. Blowing just shifts the debris so it's ready to get
straight back on to the sensor cover glass.
Many shy away
from wet cleaning on basis it is difficult and possibly a simple way
to damage the sensor cover glass. It is actually quite straightforward
if done properly. Should you buy an expensive kit? Not necessary.
You can even make your own cleaning pads. One thing to warn is using
dusty cloths - especially micro-fibre construction - is to be firmly
avoided. One of the best "cloths" to use is a soft and clean
cotton handkerchief. Put one aside for such use. One special word
of caution! Inside many camera bodies near the opening and where the
mirror rests when UP can be small strips of foam rubber. Be careful
to NOT damage them.
If you can,
obtain some Methanol (cheap if from a Pharmacist or more expensive
if bought as a commercial product, Eclipse solution) - if not some
(as close to 100% as possible) Industrial Alcohol and be able to drip
a couple of drops on the end of the pad described below, so ideal
have in small bottle with dropper top. You will only need about 50ml
for many cleans - although one good wet clean should mean only "puff,
brush and suck" required for a long time before any need for
a wet clean to be repeated.
all the main procedures are detailed above so will not be repeated
again. * Get a new pencil with an eraser tip. Cut a strip off the
handkerchief so is about 2" wide by 4" long. Fold the long
sides into the centre and repeat, until you have a "folded"
strip roughly the width of the eraser end on the pencil - as a guide
that should be about 3/8" wide for the folded material. Place
the middle on the eraser end and pull the two ends up tightly on opposite
sides and secure tighly in place with some adhesive tape. Wrap some
of the tape around near the end so it cannot slip in use.
the blowing and sucking routine per first part, now with liquid on
the end, wipe across, round, up and down and side to side with only
light pressure - the rubber eraser will ensure decent contact pressure
through the cloth pad and the several layers will ensure the liquid
does not dry out too rapidly and also ensure, as acting as a pad,
no great pressure can damage the sensor cover glass. Ideally, have
a magnifier to be able to view the sensor glass cover to see if clean.
Replace the pad and repeat. Don't worry about this sort-of gentle
scrubbing routine. One tip is if you think you have put too much liquid
on the pad - wipe it across the white paper to reduce the amount before
using - obviously wipe the paper "in case" before using
with side of your hand (not fingers as they hold grease).
wet clean will leave some slight smears on the surface. To finish
(yes, really - it works - I have cleaned many sensors this way with
no damage or ill effects!) change the pad again and use it dry to
finally "polish" the cover glass - if necessary, hold a
single layer over lips (so as not to project any small particles of
one's own mouth liquids) and huff into the body to "steam"
the glass and wipe. It really does work and will produce a clean (safely
too) sensor. I have been cleaning client's sensors for many years
to their complete satisfaction. Many had even previously sent their
cameras back to the manufacturers or to agents who advertise sensor
cleaning - at high cost of postage and cleaning charges - only to
find their sensors were not really well cleaned at all.
* You may of
course consider it sensible, as inexpensive, to obtain and prepare
several pencils in readiness before starting so can easily swap as
After any wet
clean - finish as you would for just the dry cleaning method - hold
camera upside down, blow and vacuum before finishing. All as described
for finishing above.
clothing that can shed fibres or dust - also have bare arms. I normally
just put hands under tap and rub some up arms and dry just before
any cleaning session. Obviously, don't let any nose drippings drop
on the sensor either!
Clean the nylon
bristles in a small amount of warm water with only a couple of drops
of washing-up liquid in such as a shallow saucer, finishing by thoroughly
washing under a running tap for a moment or two, before finally shaking
to get as dry as possible, then ideally hanging in a dust-free place
to dry before putting away inside a clean plastic bag to keep clean
for future use. Store remainder of hanky in similar bag to keep clean.
If you think it has attracted any dust - wash with next household
wash, then dry and put away.