d70 spot

I have a spot that keeps appearing on my images. I have to remove them
with my image editing software. The problem is that I blow some air into
the front of the camera, presumably blowing away the dust particle, and can
then take about a dozen shots after which the spot appears again, in exactly
the same place. It's not a speck of dust getting blown around as it would
be improbable for it to settle down in the same place each time, and anyway,
it takes about a dozen shots before it reappears at all. Is this just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I use).

james wrote:
I have a spot that keeps appearing on my images. I have to remove them
with my image editing software. The problem is that I blow some air into
the front of the camera, presumably blowing away the dust particle, and can
then take about a dozen shots after which the spot appears again, in exactly
the same place. It's not a speck of dust getting blown around as it would
be improbable for it to settle down in the same place each time, and anyway,
it takes about a dozen shots before it reappears at all. Is this just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I use).



Sounds like it is on the imager; it can happen when you change
lenses. There are some good ways to clean them. Look up Visible
Dust with Google. I use their brushes on my EOS 20D.

Phil

Assuming that when you say that you're blowing air into the front of
the camera you mean that you're blowing air into the front with the
lens off, I'd say that you're just blowing on the mirror and that the
sensor's dirty. Someone mentioned using the VisibleDust products.
They're good but I would recommend using a traditional blower first.
It sounds like you might already have one (assuming that you're using a
blower and not your mouth). But I myself like the Giottos Rocket Air
Blower ($10 from B&H for the medium version). I have a D70s and found
a spot on my sensor (yesterday, in fact). One puff from that puppy and
the spot is gone. I can't remember if the D70 has it; but the D70s has
a mirror lock-up function (actually, the D70 probably has it after the
firmware upgrade that brings it up to date with the D70s). Activate
the mirror lock-up and the mirror moves out of the way, revealing the
sensor. Don't touch the sensor and don't squeeze the hell out of the
blower (and don't use canned air on it). Just puff a little air onto
it. Hopefully, the debris will simply float away. If not, then you
might try a tad more air pressure or you then might want to consider
one of the VisibleDust products.

Kevin



james wrote:
I have a spot that keeps appearing on my images. I have to remove them
with my image editing software. The problem is that I blow some air into
the front of the camera, presumably blowing away the dust particle, and can
then take about a dozen shots after which the spot appears again, in exactly
the same place. It's not a speck of dust getting blown around as it would
be improbable for it to settle down in the same place each time, and anyway,
it takes about a dozen shots before it reappears at all. Is this just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I use).

Before someone yells at me... Yes, VisibleDust has a traditional type
blower as well, similar to the Giottos Rocket Air Blower I mentioned.
I was initially referrring to VisibleDust's brushes. I would use a
blower first before using a brush.

Thanks.
Kevin


k-man wrote:
Assuming that when you say that you're blowing air into the front of
the camera you mean that you're blowing air into the front with the
lens off, I'd say that you're just blowing on the mirror and that the
sensor's dirty. Someone mentioned using the VisibleDust products.
They're good but I would recommend using a traditional blower first.
It sounds like you might already have one (assuming that you're using a
blower and not your mouth). But I myself like the Giottos Rocket Air
Blower ($10 from B&H for the medium version). I have a D70s and found
a spot on my sensor (yesterday, in fact). One puff from that puppy and
the spot is gone. I can't remember if the D70 has it; but the D70s has
a mirror lock-up function (actually, the D70 probably has it after the
firmware upgrade that brings it up to date with the D70s). Activate
the mirror lock-up and the mirror moves out of the way, revealing the
sensor. Don't touch the sensor and don't squeeze the hell out of the
blower (and don't use canned air on it). Just puff a little air onto
it. Hopefully, the debris will simply float away. If not, then you
might try a tad more air pressure or you then might want to consider
one of the VisibleDust products.

Kevin



james wrote:
I have a spot that keeps appearing on my images. I have to remove them
with my image editing software. The problem is that I blow some air into
the front of the camera, presumably blowing away the dust particle, and can
then take about a dozen shots after which the spot appears again, in exactly
the same place. It's not a speck of dust getting blown around as it would
be improbable for it to settle down in the same place each time, and anyway,
it takes about a dozen shots before it reappears at all. Is this just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I use).

I don't understand how you could come to that conclusion based only on
what James posted. He said that he tried shooting air into the front
of the camera. If he's not using mirror lock-up then there's a strong
chance that he's hitting the mirror only and not the sensor. Thus, if
there's dirt on the sensor, it will remain on the sensor and show up
shot after shot.

Kevin


wrote:
Thus spake james ) unto the assembled multitudes:
I have a spot that keeps appearing on my images. I have to remove them
with my image editing software. The problem is that I blow some air into
the front of the camera, presumably blowing away the dust particle, and can
then take about a dozen shots after which the spot appears again, in exactly
the same place. It's not a speck of dust getting blown around as it would
be improbable for it to settle down in the same place each time, and anyway,
it takes about a dozen shots before it reappears at all. Is this just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I use).

All the respondants so far seem to think it's dirt, but James has said the
spot re-appears in the same place after cleaning, and - crucially - after a
dozen or so shots. The symptoms suggest that it's a noise problem -
possibly a thermal issue - with the CCD or electronics.


--

Andy Clews
University of Sussex
Remove DENTURES if replying by email

I am using mirror lock up. I know its not recommended but I use compressed
air from a can to blow dirt out. The spot on a 6 by 4 print is about 2mm
in diameter and only shows up on a blue sky. It definitely reappears in the
same place after about a dozen shots. I'm not technically minded but it
seems rather improbable?


"k-man" wrote in message
oups.com...
I don't understand how you could come to that conclusion based only on
what James posted. He said that he tried shooting air into the front
of the camera. If he's not using mirror lock-up then there's a strong
chance that he's hitting the mirror only and not the sensor. Thus, if
there's dirt on the sensor, it will remain on the sensor and show up
shot after shot.

Kevin


wrote:
Thus spake james ) unto the assembled multitudes:
I have a spot that keeps appearing on my images. I have to remove
them
with my image editing software. The problem is that I blow some air
into
the front of the camera, presumably blowing away the dust particle,
and can
then take about a dozen shots after which the spot appears again, in
exactly
the same place. It's not a speck of dust getting blown around as it
would
be improbable for it to settle down in the same place each time, and
anyway,
it takes about a dozen shots before it reappears at all. Is this
just a
highly improbable action by a speck of dust or something to do with the
camera that is more complicated? (It does not matter which lens I
use).

All the respondants so far seem to think it's dirt, but James has said
the
spot re-appears in the same place after cleaning, and - crucially - after
a
dozen or so shots. The symptoms suggest that it's a noise problem -
possibly a thermal issue - with the CCD or electronics.


--

Andy Clews
University of Sussex
Remove DENTURES if replying by email

james wrote:
I am using mirror lock up. I know its not recommended but I use compressed
air from a can to blow dirt out. The spot on a 6 by 4 print is about 2mm
in diameter and only shows up on a blue sky. It definitely reappears in the
same place after about a dozen shots. I'm not technically minded but it
seems rather improbable?


You need to clean the sensor. Blowing air in there is not a good
idea .. and apparently not solving the problem. Again, look at
Visible Dust; works well with my 20D (which has a specific
Cleaning mode in the menu).

Phil

On Sat, 17 Jun 2006 18:03:55 +0100, james wrote:

I am using mirror lock up. I know its not recommended but I use
compressed air from a can to blow dirt out. The spot on a 6 by 4 print
is about 2mm in diameter and only shows up on a blue sky. It definitely
reappears in the same place after about a dozen shots. I'm not technically
minded but it seems rather improbable?

Perhaps a cluster of the sensor's elements are flaky and stop
functioning properly when the sensor heats up? Compressed air would
cool the sensor. If you stop using the camera when the spot
appears, such as by turning it off for an hour, when you resume
shooting does the spot reappear immediately, or only after another
dozen shots are taken?

"james" wrote in message
...
I am using mirror lock up. I know its not recommended but I use
compressed air from a can to blow dirt out. The spot on a 6 by 4
print is about 2mm in diameter and only shows up on a blue sky. It
definitely reappears in the same place after about a dozen shots. I'm
not technically minded but it seems rather improbable?

Spots due to dust or pollen on the sensor's cover-glass or the
AA-filter in front of the sensor will be more visible at small
apertures (larger f/ number). Maybe the re-appearance is due to
smaller f/ number being used.

Bart

james wrote:
The spot on a 6 by 4 print is about 2mm
in diameter and only shows up on a blue sky. It definitely reappears in the
same place after about a dozen shots. I'm not technically minded but it
seems rather improbable?

Can you check the exif data ona couple of those files and see if you
are changing the aperture? At f/22 for example you might see the spot
while at f/4 you won't see it ... just another variable to check but
this would explain why it comes and goes from the same area.

Bill