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Avoiding dust ?

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Anonymous
May 6, 2005 3:37:42 PM

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

Hi all ... another newbie here .

I've got a new D70s on order that I plan to use for shooting mainly car
racing photos.... certainly a dusty environment...
I'll be using the kit lens, and a 70-300 zoom.

I've been reading so much about the "dust on the sensor" issue, that I'm
getting a bit paranoid about it .

Has anyone come up with a good way to at least try to "guard against "
getting dust in the camera when changing lenses ?

Thanks -=JL

More about : avoiding dust

Anonymous
May 6, 2005 4:02:48 PM

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

"Jim Locking" <jlocking@nospamsympatico.ca> writes:

> Hi all ... another newbie here .
>
> I've got a new D70s on order that I plan to use for shooting mainly car
> racing photos.... certainly a dusty environment...
> I'll be using the kit lens, and a 70-300 zoom.
>
> I've been reading so much about the "dust on the sensor" issue, that I'm
> getting a bit paranoid about it .
>
> Has anyone come up with a good way to at least try to "guard against "
> getting dust in the camera when changing lenses ?

Minimize lens-off time, and hold the body with the opening *down*
while the lens is off. However, really doing this in the field
requires at least 3 hands.
--
David Dyer-Bennet, <mailto:D d-b@dd-b.net>, <http://www.dd-b.net/dd-b/&gt;
RKBA: <http://noguns-nomoney.com/&gt; <http://www.dd-b.net/carry/&gt;
Pics: <http://dd-b.lighthunters.net/&gt; <http://www.dd-b.net/dd-b/SnapshotAlbum/&gt;
Dragaera/Steven Brust: <http://dragaera.info/&gt;
Anonymous
May 6, 2005 4:02:49 PM

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

David Dyer-Bennet wrote:
>
> Minimize lens-off time, and hold the body with
> the opening *down* while the lens is off.
> However, really doing this in the field
> requires at least 3 hands.

and thus you win "The Laugh of the Day Award"

> --
> David Dyer-Bennet, <mailto:D d-b@dd-b.net>, <http://www.dd-b.net/dd-b/&gt;
> RKBA: <http://noguns-nomoney.com/&gt; <http://www.dd-b.net/carry/&gt;
> Pics: <http://dd-b.lighthunters.net/&gt; <http://www.dd-b.net/dd-b/SnapshotAlbum/&gt;
> Dragaera/Steven Brust: <http://dragaera.info/&gt;
Related resources
Anonymous
May 6, 2005 5:21:36 PM

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

From: "Jim Locking" <jlocking@nospamsympatico.ca>
Subject: Avoiding dust ?
Date: Friday, May 06, 2005 9:37 AM

Hi all ... another newbie here .

I've got a new D70s on order that I plan to use for shooting mainly car
racing photos.... certainly a dusty environment...
I'll be using the kit lens, and a 70-300 zoom.

I've been reading so much about the "dust on the sensor" issue, that I'm
getting a bit paranoid about it .

Has anyone come up with a good way to at least try to "guard against "
getting dust in the camera when changing lenses ?

Thanks -=JL

The newer DSLR lenses have rubber seals which helps. As Alan said, let
gravity help you by holding the camera lens down when changing lenses and
make sure the lens you are putting on is clean. Clean around the lens mount
before changing lenses. And yes, three hands helps, but it can be done. I
used to shoot the Grand Prix circuit and there was almost always a place to
change a lens. Of course, there's a lot less dust and dirt around a Grand
Prix track out in the woods than there is at a NASCAR track. Unless you are
in the pits, you will probably find yourself using the 70~300 lens most of
the time.

Have fun, don't worry, and everything can be fixed after the fact. If you
do pick up some dust your first line of defense should be a good manual
blower. Every once in awhile take a shot of a clear sky at f22 and see if
you've picked up anything.

Once I shot an entire assignment with a hair stuck in the track on the
shutter curtain hanging down into the frame on a 35mm camera. So, this
problem is not just a digital problem. Yes, I checked everything before
shooting, but didn't see the problem 'till the film was developed. And that
was BP (Before Photoshop).
Anonymous
May 6, 2005 7:03:25 PM

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

Jim Locking wrote:


> Has anyone come up with a good way to at least try to "guard against "
> getting dust in the camera when changing lenses ?

Change inside the perimeter of the bag. If it's windy, dust tends to
swirl and settle on the downwind side of an obstacle (you, bag, bag top).

Don't worry it too much either. Sensor dust does not show very much on
phots at f/11 or faster, esp. if there is a lot of 'stuff' in the scene.

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 6, 2005 9:11:27 PM

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

Jim Locking wrote:
> Has anyone come up with a good way to at least try to "guard against "
> getting dust in the camera when changing lenses ?

I use a small clear plastic bag and change the lens inside the bag if I have
to. It's also handy to have if it's raining.
Anonymous
May 6, 2005 9:25:40 PM

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

In article <8bMee.23995$3U.1162469@news20.bellglobal.com>,
Jim Locking <jlocking@nospamsympatico.ca> wrote:
>Hi all ... another newbie here .
>
>I've got a new D70s on order that I plan to use for shooting mainly car
>racing photos.... certainly a dusty environment...
>I'll be using the kit lens, and a 70-300 zoom.
>
>I've been reading so much about the "dust on the sensor" issue, that I'm
>getting a bit paranoid about it .

Easy to do, if you read too much. So far, I haven't had obvious
dust problems on my D70, and I change lens fairly often. And until I
get obvious dust problems, I probably won't do the test for dust to see
just how bad it happens to be. :-)

You'll probably be shooting fairly wide open to favor shutter
speeds, given your subjet matter, so you are not likely to be seriously
inconvenienced by any dust which does occur. You need to be stopped
fairly far down to make it visible -- and have a very even lighting to
make it obvious.

>Has anyone come up with a good way to at least try to "guard against "
>getting dust in the camera when changing lenses ?

Well ... you *could* get two camera bodies, one with the "kit"
lens, and one body only, and put the 70-300mm on that lens. That way,
you don't need to change lenses in the field.

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 ---
May 7, 2005 12:35:48 AM

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

On Fri, 6 May 2005 11:37:42 -0400, "Jim Locking"
<jlocking@nospamsympatico.ca> wrote:

>Hi all ... another newbie here .
>
>I've got a new D70s on order that I plan to use for shooting mainly car
>racing photos.... certainly a dusty environment...
>I'll be using the kit lens, and a 70-300 zoom.
>
>I've been reading so much about the "dust on the sensor" issue, that I'm
>getting a bit paranoid about it .
>
>Has anyone come up with a good way to at least try to "guard against "
>getting dust in the camera when changing lenses ?
>
>Thanks -=JL
>
Do it indoors.
Anonymous
May 7, 2005 3:57:56 PM

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

"Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
news:D 5gf1r$823$1@inews.gazeta.pl...
> Jim Locking wrote:
>
>
> > Has anyone come up with a good way to at least try to "guard against "
> > getting dust in the camera when changing lenses ?
>
> Don't worry it too much either. Sensor dust does not show very much on
> phots at f/11 or faster, esp. if there is a lot of 'stuff' in the scene.

Hi Alan.
Can you clear this up for me?

If the dust is on the sensor (i.e. at or very near the focal plane), how
does the f stop of the lens affect the visibility of the dust?

Now, if the dust was on the lens filter, or elsewhere removed from the focal
plane, I'd understand the DOF argument here -but- if its on the sensor then
surely its only illumination (and pattern interference) that affects its
visibility.

Sorry if this issue has been flogged to death before.

--
Jeff R.
Anonymous
May 7, 2005 3:57:57 PM

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

In article <427c20a3$0$4657$afc38c87@news.optusnet.com.au>,
Jeff R <contact.me@this.ng> wrote:
>
>"Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
>news:D 5gf1r$823$1@inews.gazeta.pl...

[ ... ]

>> Don't worry it too much either. Sensor dust does not show very much on
>> phots at f/11 or faster, esp. if there is a lot of 'stuff' in the scene.
>
>Hi Alan.
>Can you clear this up for me?
>
>If the dust is on the sensor (i.e. at or very near the focal plane), how
>does the f stop of the lens affect the visibility of the dust?
>
>Now, if the dust was on the lens filter, or elsewhere removed from the focal
>plane, I'd understand the DOF argument here -but- if its on the sensor then
>surely its only illumination (and pattern interference) that affects its
>visibility.

The dust particles are not directly on the sensor, but rather on
the anti-aliaising filter which is above the filters for the individual
pixels.

The thickness of the anti-aliasing filter is sufficient so the typical
dust particle is smaller than the circle of incoming light focused on a
given pixel at the more open apertures. Only when you are at the
smallest apertures (numerically largest) is a given pixel totally
blocked by the dust.

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 ---
May 7, 2005 3:57:58 PM

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

DoN. Nichols wrote:

>
> The thickness of the anti-aliasing filter is sufficient so the typical
> dust particle is smaller than the circle of incoming light focused on a
> given pixel at the more open apertures. Only when you are at the
> smallest apertures (numerically largest) is a given pixel totally
> blocked by the dust.
>


But wouldn't this dust affect the image quality even if it didn't "totally
block the pixel"? I mean you can cover a lens front element with dust and
you won't see any of the dust -spots- but it hurts the image quality none
the less.

--

Stacey
Anonymous
May 7, 2005 5:10:22 PM

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

"DoN. Nichols" <dnichols@d-and-d.com> wrote in message
news:D 5ha7s$20r$1@fuego.d-and-d.com...
> In article <427c20a3$0$4657$afc38c87@news.optusnet.com.au>,
> The dust particles are not directly on the sensor, but rather on
> the anti-aliaising filter which is above the filters for the individual
> pixels.
>
> The thickness of the anti-aliasing filter is sufficient so the typical
> dust particle is smaller than the circle of incoming light focused on a
> given pixel at the more open apertures. Only when you are at the
> smallest apertures (numerically largest) is a given pixel totally
> blocked by the dust.
>
> Enjoy,
> DoN.


Thanks Don.
That makes sense.

--
Jeff R.
Anonymous
May 7, 2005 6:07:09 PM

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

Jeff R wrote:

> "Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
> news:D 5gf1r$823$1@inews.gazeta.pl...
>
>>Jim Locking wrote:
>>
>>
>>
>>>Has anyone come up with a good way to at least try to "guard against "
>>>getting dust in the camera when changing lenses ?
>>
>>Don't worry it too much either. Sensor dust does not show very much on
>>phots at f/11 or faster, esp. if there is a lot of 'stuff' in the scene.
>
>
> Hi Alan.
> Can you clear this up for me?
>
> If the dust is on the sensor (i.e. at or very near the focal plane), how
> does the f stop of the lens affect the visibility of the dust?

When at large apertures, the light striking a given point on the sensor
arrives from a wide cone. So most of the light "ducks under" the dust
and it has little affect on the image. Most images usually have so much
other detail, that any remaining effect is obscured.

When at small apertures, the cone of light going to the point where the
dust is, is quite narrow, so then the dust blocks more of the light and
it shows in the image. Again, most scenes have detail that obscures
this, but as the dust count increases, the 'hits' in low detail areas
goes up and you begin to think about cleaning.

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 8, 2005 12:07:21 AM

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

Stacey wrote:
> DoN. Nichols wrote:
>
>
>>The thickness of the anti-aliasing filter is sufficient so the typical
>>dust particle is smaller than the circle of incoming light focused on a
>>given pixel at the more open apertures. Only when you are at the
>>smallest apertures (numerically largest) is a given pixel totally
>>blocked by the dust.
>>
>
>
>
> But wouldn't this dust affect the image quality even if it didn't "totally
> block the pixel"? I mean you can cover a lens front element with dust and
> you won't see any of the dust -spots- but it hurts the image quality none
> the less.
>
If you covered the low pass filter with fine dust, then yes - it
probably would. A few small specks won't make any visible difference.
But a big hair or dust bunny you will see - even at relatively wide
aperture.

I was a bit paranoid about dust - but similar to what Don Nichols
reports, after many lens changes in the field, I have yet to have an
actual image affected. I haven't tried it yet - but have the gear
ready, and wouldn't hesitate to clean the sensor myself. In a bizarre
way - I had been looking forward to the challenge of doing it. Then
again, I have had some experience disassembling and cleaning lenses.
(Last jobs were de-gumming siezed aperture blades on a Nikkor 50mm, and
removing grunge that accumulated behind the front elements on a long
Nikkor zoom - there was enough grunge to lead me to believe that it did
cause problems - and it certainly looked very ugly)

I think (hope) sensor cleaning is probably relatively easy - so long as
you have the right tools, very good lighting, steady hands, and as clean
an environment as possible.

I wouldn't totally trust some of the proprietary cleaning solutions. If
they are pure methanol or isopropynol, then save lots of $$ and buy the
stuff yourself. Personally I wouldn't use anything with claimed
"anti-static" additives. If there really is something in the solution
that might act to dissipate a static charge, then chances are it is
going to leave a residue on the surface that might do the reverse of
what you want - if something does land on the surface of the glass, then
the anti-static chemical might actually help it to stick.

An (OT) parallel is "bead oil" used in carwash machines when you get a
so called "wash and wax". (the "wax" isn't wax). The "bead oil" in the
formula forms a very thin (molecular level) invisible film on the paint.
Water beads up - to give you the impression that it is a clean "waxed"
repellent surface. In actual fact, your car gets dirty again faster -
because when dust and dirt hits the surface, it sticks - and it doesn't
wash off again easily - until next time you get a "wash and wax". It is
a good business model.
Anonymous
May 8, 2005 2:53:30 PM

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

"Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
news:D 5j04c$obp$1@inews.gazeta.pl...
> Jeff R wrote:
>
> > "Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
> > news:D 5gf1r$823$1@inews.gazeta.pl...
> >
> > If the dust is on the sensor (i.e. at or very near the focal plane), how
> > does the f stop of the lens affect the visibility of the dust?
>
> When at large apertures, the light striking a given point on the sensor
> arrives from a wide cone. So most of the light "ducks under" the dust
> and it has little affect on the image. Most images usually have so much
> other detail, that any remaining effect is obscured.
>
> When at small apertures, the cone of light going to the point where the
> dust is, is quite narrow, so then the dust blocks more of the light and
> it shows in the image. Again, most scenes have detail that obscures
> this, but as the dust count increases, the 'hits' in low detail areas
> goes up and you begin to think about cleaning.


Thanks Alan.
Your reply serendipitously explains ordinary old DOF, too.

Cheers
--
Jeff R
Anonymous
May 8, 2005 4:05:15 PM

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

Jeff R wrote:

> Thanks Alan.
> Your reply serendipitously explains ordinary old DOF, too.

Yes, it is indeed related.

Actually, Don Nichols expanation has the critical piece of information
in the dust being on top of the A/S filter (or other transparent cover
to the image sensor) providing the depth for the phenomena to occur as
it does.

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.
!