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Strange dirt problem

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Anonymous
May 22, 2005 5:53:09 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

I have a D70, about 2 weeks old.

At very high f-stops, there are 5 or 6 dirt specks on the images, which
become blurred at lower f-stops. (specks are always in the same place)
Replacing the lens made no difference, but there is no obvious dirt on
the sensor, and taking a shot with no lens gives no dirt. Also, if the
dirt were on the sensor, it would look the same no matter what the
f-stop, right?

So it's not the body, and it's not the lens...

Any ideas???

More about : strange dirt problem

Anonymous
May 22, 2005 7:12:56 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

What do people think about using the high pressure air canisters sold
for cleaning keyboards, etc.? Too violent?
Anonymous
May 22, 2005 8:14:48 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

well, I just used a foot pump for blowing up air mattresses with
perfect results - thank you all for your help.
Related resources
Anonymous
May 22, 2005 8:37:21 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

good point - so should I get one of those little brush-blowers (and use
it without the brush on)?
Anonymous
May 22, 2005 9:14:45 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

In article <1116795189.099525.59020@g14g2000cwa.googlegroups.com>,
<google.20.jbloggs@xoxy.net> wrote:
>I have a D70, about 2 weeks old.
>
>At very high f-stops, there are 5 or 6 dirt specks on the images, which
>become blurred at lower f-stops.

Numerically lower -- as in larger opening?

> (specks are always in the same place)
>Replacing the lens made no difference,

The dust on the lens *can't* form an image on the sensor -- it
is way out of focus, so changing the lens won't do anything for this.

> but there is no obvious dirt on
>the sensor, and taking a shot with no lens gives no dirt. Also, if the
>dirt were on the sensor, it would look the same no matter what the
>f-stop, right?

It is on top of two filters above the sensor, so it is far
enough away that anything but a very narrow beam of light will reach
individual pixels through multiple paths -- most missing the dust
particles. Only when your lens is stopped way down does the light form
a narrow enough cone that the dust particles do the damage to the image.

>So it's not the body, and it's not the lens...

It *is* the sensor. You need to clean it.

Note that the image is inverted on the sensor, so what may
appear to be in the upper-right-hand corner of the image will be on the
lower-left-hand corner of the sensor.

And it doesn't take a very big bit of dust to show up as
blocking one or two pixels. You might not be able to see them on the
sensor without a good long-focus microscope (the stereo-zoom one by
either B&L or AO would be excellent for this purpose -- but you don't
need to *see* it to remove it.

First try a bulb blower -- which may be sufficient for the
purpose. (The ones sold for cleaning out earwax at the drugstore are
a nice size -- but use a *new* one for the purpose, not one which has
already been used for its intended purpose.)

If that does not work, you may need to get the kit with the
"eclipse" (alcohol) and the "pec pads" (lint-free cloth around a
specially made flexible plastic holder. Hopefully, someone else will
remember the URL which describes (and offers) these products.

You *could* take it back to Nikon for cleaning -- but it will
acquire more as you change lenses, so it makes more sense to learn to do
it yourself, so you won't be without the camera for several days each
time.

Best of luck,
DoN.

--
Email: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
Anonymous
May 22, 2005 9:59:39 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

DoN. Nichols wrote:
> First try a bulb blower -- which may be sufficient for the
> purpose. (The ones sold for cleaning out earwax at the drugstore are
> a nice size -- but use a *new* one for the purpose, not one which has
> already been used for its intended purpose.)

Er...by the way, can anyone tell me how to get earwax off the sensor of
my D70? Thanks.
Anonymous
May 22, 2005 10:07:22 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:

> So it's not the body, and it's not the lens...

dust specs on the sensor cover. At higher f/ the 'cone' of light is
narrow and so the spots get silhouetted. At lower f/ the cone is wide
and light gets 'under' the dust. Note that the dust is on the cover of
the sensor so at wide aperture there is room for the light to get around
the spec.

See your manual for instructions on using an ear syringe or similar to
blow off the dust w/o touching the sensor cover.

Cheers,
Alan.


--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.
Anonymous
May 22, 2005 11:35:37 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:
> well, I just used a foot pump for blowing up air mattresses with
> perfect results - thank you all for your help.

Cool, but what are you going to use for your camera sensor? :D 
Anonymous
May 23, 2005 1:43:04 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On Sun, 22 May 2005 19:35:37 -0400, Cynicor wrote:

> google.20.jbloggs@xoxy.net wrote:
>> well, I just used a foot pump for blowing up air mattresses with
>> perfect results - thank you all for your help.
>
> Cool, but what are you going to use for your camera sensor? :D 

Maybe a lima bean or two?
Anonymous
May 23, 2005 2:50:43 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:

> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?
>
>

Let's just say that it would be an act of supreme idiocy.
Anonymous
May 23, 2005 3:14:26 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:
> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?

The propellant in high pressure air canisters contains an inert gas that
will leave a slight film (pardon the pun) on your CCD. Not good.
Anonymous
May 23, 2005 3:17:04 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net <google.20.jbloggs@xoxy.net> wrote:
>
> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?

Not only are they too violent, but they may become too cold, and most
cannisters contain components that will actually add sticky dirt to
the sensor and make the situation worse. Do not attempt this.

--
Zed Pobre <zed@resonant.org> a.k.a. Zed Pobre <zed@debian.org>
PGP key and fingerprint available on finger; encrypted mail welcomed.
Anonymous
May 23, 2005 5:01:24 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

In article <kTbke.650$dZ5.138050@news20.bellglobal.com>,
Gaderian <nospam@anisp.com> wrote:
>google.20.jbloggs@xoxy.net wrote:
>> What do people think about using the high pressure air canisters sold
>> for cleaning keyboards, etc.? Too violent?
>
>The propellant in high pressure air canisters contains an inert gas that
>will leave a slight film (pardon the pun) on your CCD. Not good.

It depends on the type of canister. I've got some made by
Leland Co. "Power Clean" which works from screw-in CO2 cartridges. The
aperture at the end of the nozzle is quite small, so at any reasonable
distance, the airflow is quite reasonable. However, if you hold it so
the cartridge is above the valve, you will get liquid CO2, which will
freeze the surface which it hits. When it evaporates (very quickly), it
will leave nothing behind, but the thermal shock -- especially to
a silicon device as large as the sensor, could cause significant damage.

Enjoy,
DoN.

--
Email: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
Anonymous
May 23, 2005 9:27:17 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

dnichols@d-and-d.com (DoN. Nichols) wrote:

> It depends on the type of canister. I've got some made by
> Leland Co. "Power Clean" which works from screw-in CO2 cartridges.
> The aperture at the end of the nozzle is quite small, so at any
> reasonable distance, the airflow is quite reasonable. However, if you
> hold it so the cartridge is above the valve, you will get liquid CO2,
> which will freeze the surface which it hits. When it evaporates (very
> quickly), it will leave nothing behind, but the thermal shock --
> especially to a silicon device as large as the sensor, could cause
> significant damage.
>
> Enjoy,
> DoN.
>

When the sensor freezes, it's freezing water vapor out of the air onto
the sensor. This is not usually pure water and when the ice sublimates
it leaves behind dissolved salts and minerals.
May 23, 2005 1:44:19 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

DoN. Nichols wrote:


> First try a bulb blower -- which may be sufficient for the
> purpose. (The ones sold for cleaning out earwax at the drugstore are
> a nice size -- but use a *new* one for the purpose, not one which has
> already been used for its intended purpose.)
>
> If that does not work, you may need to get the kit with the
> "eclipse" (alcohol) and the "pec pads" (lint-free cloth around a
> specially made flexible plastic holder. Hopefully, someone else will
> remember the URL which describes (and offers) these products.
>
> You *could* take it back to Nikon for cleaning -- but it will
> acquire more as you change lenses, so it makes more sense to learn to do
> it yourself, so you won't be without the camera for several days each
> time.
>
I agree with you 100%
The URL is probably this one:
http://www.pbase.com/copperhill/ccd_cleaning

I use his method, but use high purity isopropyl alcohol, not eclipse. I
think eclipse is high purity methanol at a very high price. Methanol
will evaporate a little faster. Isopropynol evaporates fast enough from
my experience.

I made my own "wand" using a piece of plastic kitchen spatula, cut to
14mm wide, shaped as described on the above site, and clamped firmly in
the tongs of a stylus knife handle so that I can hold it very easily
without it rotating in my fingers.
Results of the two cleans I needed were 100% first time.

I practised my technique using a microscope slide before tyring the real
thing. I think that was a good idea.
Anonymous
May 23, 2005 1:55:43 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

<google.20.jbloggs@xoxy.net> wrote in message
news:1116799976.796917.264860@z14g2000cwz.googlegroups.com...
> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?
>

The latest issue of Photoshop User has an article that recommends a
variation with compresed air. The author states that a blast of compressed
air across the tip of a fine bristle brush will provide enough electrostatic
charge to attract dust from the sensor when brushed lightly. Seems much
simpler than wiping the sensor filter.

Has anyone else tried this technique, and is there risk that the static
charge could damage the sensor? I ask because I need to clean my 20D.

Sonrise
Anonymous
May 23, 2005 2:22:29 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:

> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?

Do not aim inside your camera. The blast is strong enough to cause
mechanical damage (mirror assembly, shutter blades, etc.).

If you do use such canned air:

1) point away from anything valuable, give a couple short blasts to
clear propellant.

2) Always hold the can vertical to prevent propellant from getting into
to the works and out onto any surfaces.

I use canned air to blow off film before scanning, but always with the
two points above observed. I'd never point it at equipment.

Cheers,
Alan



--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.
May 23, 2005 2:51:30 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:
> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?
>
Yes. Don't use them on your camera. Use them on your keyboard etc.
May 23, 2005 3:30:40 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

google.20.jbloggs@xoxy.net wrote:

> well, I just used a foot pump for blowing up air mattresses with
> perfect results - thank you all for your help.
>
Okay - I suggest that probably wasn't a great idea, but you got away
with it. Pumps with rubber components, and the air mattresses
themselves are likely to have lots of powders that are used as
anti-blocking (to stop the surface sticking to itself) and anti-oxidants
floating around in liberal quantities. (Talc, Zinc Stearate, etc) The
right pump, with good clean hoses, and never used to inflate a real
rubber lined air mattress might be okay.
Anonymous
May 23, 2005 10:56:29 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

<google.20.jbloggs@xoxy.net> wrote:

> What do people think about using the high pressure air canisters sold
> for cleaning keyboards, etc.? Too violent?

Yes, not good. What you need to go this route is *low* pressure compressed
CO2 that does not contain any lubricants or chemical propellants. The kind
of CO2 cartridges that are used to make whipped cream or seltzer are what
to look for -- food grade ones are more expensive, and they don't last very
long at all, but they will blow clean. And they won't freeze as long as
you don't turn them upside down -- compressed CO2 does get cold, but since
these are not highly compressed, the CO2 is at room temperature by the time
it gets out of the blower.

Don't use the "canned air" products; they are very much unclean, and blow
too hard. And don't use CO2 cartridges made for BB guns or similar
applications.

--
Jeremy | jeremy@exit109.com
June 6, 2005 6:20:12 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

RM Wrote:
> Sonrise wrote:
> The latest issue of Photoshop User has an article that recommends a
> variation with compresed air. The author states that a blast of
> compressed
> air across the tip of a fine bristle brush will provide enough
> electrostatic
> charge to attract dust from the sensor when brushed lightly. Seems
> much
> simpler than wiping the sensor filter.
>
> Has anyone else tried this technique, and is there risk that the
> static
> charge could damage the sensor? I ask because I need to clean my 20D.
>
> >
> I too have been using this method on a D60 and a 10D for about 8
> months. It's a quick, simple method and I find it works perfectly.
> I've noticed no image problems with either body as a result (about
> 60,000 images so far...!)


--
shadowhawk
!