Bands noted in dark frames of Nikon D70 long exposures

I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose last
night.

My problem is that I am noticing severe bands or lines in the images. This
has not been noted in any of my other photos...just these dark shots. You
can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and adjusted
the gamma up to 2.7 to bring out the effect. The below link contains that
result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run the
same dark frame test described above to confirm whether it is something
inherent in D70's or just my camera? Is there a workaround if it is common
to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

I should also point out that I was shooting in .raw mode and had noise
reduction set to off. However, I've retried my experiment using .jpg fine
and also turning NR to on and although it changes the effect somewhat, it is
still present.

Jeff
"Jeff M" wrote in message
...
I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose
last night.

My problem is that I am noticing severe bands or lines in the images.
This has not been noted in any of my other photos...just these dark shots.
You can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and
adjusted the gamma up to 2.7 to bring out the effect. The below link
contains that result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run
the same dark frame test described above to confirm whether it is
something inherent in D70's or just my camera? Is there a workaround if
it is common to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

I should also point out that I was shooting in .raw mode and had noise
reduction set to off. However, I've retried my experiment using .jpg fine
and also turning NR to on and although it changes the effect somewhat, it is
still present.

Jeff
"Jeff M" wrote in message
...
I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose
last night.

My problem is that I am noticing severe bands or lines in the images.
This has not been noted in any of my other photos...just these dark shots.
You can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and
adjusted the gamma up to 2.7 to bring out the effect. The below link
contains that result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run
the same dark frame test described above to confirm whether it is
something inherent in D70's or just my camera? Is there a workaround if
it is common to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

I should also point out that I was shooting in .raw mode and had noise
reduction set to off. However, I've retried my experiment using .jpg fine
and also turning NR to on and although it changes the effect somewhat, it is
still present.

Jeff
"Jeff M" wrote in message
...
I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose
last night.

My problem is that I am noticing severe bands or lines in the images.
This has not been noted in any of my other photos...just these dark shots.
You can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and
adjusted the gamma up to 2.7 to bring out the effect. The below link
contains that result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run
the same dark frame test described above to confirm whether it is
something inherent in D70's or just my camera? Is there a workaround if
it is common to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

On Sun, 7 Nov 2004 16:46:47 -0500, "Jeff M"
wrote:


Looks to me to be pattern noise that you brought out with the dark
field exposure. I don't know if the banding is common with the D70
but all ccd cameras have some pattern noise due to the variations in
pixel sensitivity. And I believe there are a number of programs and
procedures to subtract out pattern noise. You might try asking for
details in the the astronomical news groups.


I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose last
night.

My problem is that I am noticing severe bands or lines in the images. This
has not been noted in any of my other photos...just these dark shots. You
can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and adjusted
the gamma up to 2.7 to bring out the effect. The below link contains that
result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run the
same dark frame test described above to confirm whether it is something
inherent in D70's or just my camera? Is there a workaround if it is common
to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

On Sun, 7 Nov 2004 16:46:47 -0500, "Jeff M"
wrote:


Looks to me to be pattern noise that you brought out with the dark
field exposure. I don't know if the banding is common with the D70
but all ccd cameras have some pattern noise due to the variations in
pixel sensitivity. And I believe there are a number of programs and
procedures to subtract out pattern noise. You might try asking for
details in the the astronomical news groups.


I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose last
night.

My problem is that I am noticing severe bands or lines in the images. This
has not been noted in any of my other photos...just these dark shots. You
can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and adjusted
the gamma up to 2.7 to bring out the effect. The below link contains that
result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run the
same dark frame test described above to confirm whether it is something
inherent in D70's or just my camera? Is there a workaround if it is common
to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

Jeff M wrote:

I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose last
night.

Jeff,
you might try joining the group. There are
a lot of experienced astrophotographers there, many using a D70, who
might be able to answer your question. Also, many spectacular astrophotos
are posted. Truly outstanding work by many people.
Roger


My problem is that I am noticing severe bands or lines in the images. This
has not been noted in any of my other photos...just these dark shots. You
can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and adjusted
the gamma up to 2.7 to bring out the effect. The below link contains that
result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run the
same dark frame test described above to confirm whether it is something
inherent in D70's or just my camera? Is there a workaround if it is common
to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

Jeff M wrote:

I attempted to take some long-exposure Milky Way photos last night. I am
experienced at astrophotography with film and specialized astrophotography
ccd cameras but tried using the D70 for the first time for this purpose last
night.

Jeff,
you might try joining the group. There are
a lot of experienced astrophotographers there, many using a D70, who
might be able to answer your question. Also, many spectacular astrophotos
are posted. Truly outstanding work by many people.
Roger


My problem is that I am noticing severe bands or lines in the images. This
has not been noted in any of my other photos...just these dark shots. You
can see what I'm describing at the below links.

This is my Milky Way shot in which you can see some differently shaded
bands.

http://astroimages.org/MilkyWay-merge.jpg

The shot above is the result of layering 10, 30-second shots using Paint
Shop Pro.

To see the effect, I shot a 30-second dark frame (lens cap on) and adjusted
the gamma up to 2.7 to bring out the effect. The below link contains that
result with clear bands of light and dark.

http://astroimages.org/DSC_0002.jpg

To repeat this experiment, set your camera to take a 30" image, and leave
the lens cap on. Load the resultant image in your favorite processing
program (I use PSP9) and boost the gamma (I used 2.7 in PSP9).

I also ran a test with covering the viewfinder to ensure that it wasn't
somehow connected to stray light getting through.

Does anyone have any ideas about what I am observing? Could someone run the
same dark frame test described above to confirm whether it is something
inherent in D70's or just my camera? Is there a workaround if it is common
to all of these cameras?

Thanks for any help that anyone might provide.

Jeff

"Jeff M" wrote in news:Tf2dnVsVU4c2ChPcRVn-
:

Does anyone have any ideas about what I am observing?

Did you have autofocus on, perchance?

The Canon 20D has this issue, and autofocus motor noise at the least seems
to aggravate it.

"Jeff M" wrote in news:Tf2dnVsVU4c2ChPcRVn-
:

Does anyone have any ideas about what I am observing?

Did you have autofocus on, perchance?

The Canon 20D has this issue, and autofocus motor noise at the least seems
to aggravate it.