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Photo Forum / Digital Photography / DSLR Cameras / September 2006

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D200 owners, pls do a test for me (and for yourselves)

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noone@nospam.com - 30 Aug 2006 15:39 GMT
Hi all,

I have had a D200 for about eight months, and while I generally love it, it
has been plagued with a disturbing number of problems.

First was the long banding--I believe they replaced the sensor to fix that,
but afterward pixels started dying. First I had three dead pixels remapped,
then two months later I found about 20 new ones, which were remapped. Now, a
month later I am finding more. Has anyone else experienced anything like
this?

But the latest and greatest weirdness became apparent recently when I tried
to do a longish exposure--about 3 minutes--of the African night sky. I was
shocked to find that all four corners and the top of the frame were luminous
pink--looking like light-struck film. And the whole frame was studded with
scores of dead-looking pixels of different sizes in white, red and blue. But
they weren't dead; at shorter exposure times they behaved normally, with
more and more being "blown out" and luminescing as the exposure lengthened.
There were a few at 30 secs., more at one minute, and a whole lot more at 3
mins. I didn't have the courage to test further...Likewise the pink fringing
started at about 1 minute and grew progressively worse at longer exposure
times.

Obviously this is going back to Nikon, but I am wondering how many D200
exemplars might suffer from this kind of defect, which is not obvious in
most shooting situations. If you have a D200 and the time and inclination
please try this: Go in a dark room, put a body cap on to stop any light from
entering at the front, and perhaps the cap on the eyepiece as well, and do a
3 minute exposure at ISO 1600. I would be interested in hearing about the
results.

TIA,

Toby
Adrian Boliston - 30 Aug 2006 15:57 GMT
My D70s has a "long exposure noise reduction" setting - have you got this
setting in use?
Doug Payne - 30 Aug 2006 16:56 GMT
> And the whole frame was studded with
> scores of dead-looking pixels of different sizes in white, red and blue. But
> they weren't dead; at shorter exposure times they behaved normally, with
> more and more being "blown out" and luminescing as the exposure lengthened.

That's long-exposure noise, not dead pixels.
David Kilpatrick - 30 Aug 2006 17:24 GMT
>> And the whole frame was studded with
>> scores of dead-looking pixels of different sizes in white, red and
[quoted text clipped - 4 lines]
>
> That's long-exposure noise, not dead pixels.

Red, white and blue are not dead pixels, they are 'hot' pixels and Long
Exposure NR (dark frame subtraction) eliminates them - in theory along
with the pink glow.

David
Thomas T. Veldhouse - 30 Aug 2006 18:46 GMT
>> And the whole frame was studded with
>> scores of dead-looking pixels of different sizes in white, red and blue. But
>> they weren't dead; at shorter exposure times they behaved normally, with
>> more and more being "blown out" and luminescing as the exposure lengthened.
>
> That's long-exposure noise, not dead pixels.

OP wasn't complaining about dead pixels, OP was complaining about pink and
color noise.

Signature

Thomas T. Veldhouse
Key Fingerprint: 2DB9 813F F510 82C2 E1AE  34D0 D69D 1EDC D5EC AED1

Doug Payne - 30 Aug 2006 19:04 GMT
>>> And the whole frame was studded with
>>> scores of dead-looking pixels of different sizes in white, red and blue. But
[quoted text clipped - 4 lines]
> OP wasn't complaining about dead pixels, OP was complaining about pink and
> color noise.

OP said this:

> And the whole frame was studded with
> scores of dead-looking pixels of different sizes in white, red and blue.

Picky semantics. Get a life.
noone@nospam.com - 01 Sep 2006 13:43 GMT
Really? Bright red and blue squares exactly four pixels square?
RichA - 30 Aug 2006 18:09 GMT
> Hi all,
>
[quoted text clipped - 30 lines]
>
> Toby

Sony putting as much effort into their sensors as their batteries?
Pete D - 31 Aug 2006 09:27 GMT
>> Hi all,
>>
[quoted text clipped - 46 lines]
>
> Sony putting as much effort into their sensors as their batteries?

Same happened to your D200 too, you have such bad luck Rich?
Bill - 30 Aug 2006 21:22 GMT
>But the latest and greatest weirdness became apparent recently when I tried
>to do a longish exposure--about 3 minutes--of the African night sky. I was
>shocked to find that all four corners and the top of the frame were luminous
>pink--looking like light-struck film.

I've heard of that...I think it's just too much signal gain at high ISO
settings in dark shots. Lower the ISO to a more appropriate setting.

> And the whole frame was studded with
>scores of dead-looking pixels of different sizes in white, red and blue. But
>they weren't dead; at shorter exposure times they behaved normally, with
>more and more being "blown out" and luminescing as the exposure lengthened.
>There were a few at 30 secs., more at one minute, and a whole lot more at 3
>mins. I didn't have the courage to test further...

You should already know this, but those are called "hot pixels" and it's
actually normal. The longer the exposure time the more hot pixels will
show.

You have a noise reduction (NR) feature in the camera called dark frame
subtraction for long exposures. When enabled, it does a secondary
exposure without opening the shutter to get a completely dark comparison
for the previous shot. It does a decent job of removing the hot pixels
and any other anomalies.

The ISO setting has an effect on it too. For long exposures you should
be using ISO 100. Higher settings are not needed and introduce unwanted
noise. Limit high ISO shots to low light, such as indoor shots. For dark
or night shots where you have to use a tripod anyway, set the camera for
ISO 100 and get the best image quality.

>Obviously this is going back to Nikon, but I am wondering how many D200
>exemplars might suffer from this kind of defect, which is not obvious in
>most shooting situations.

Hot pixels happens with all digital cameras. It's nothing new.

The only thing of concern is the dead pixels. You shouldn't have that
many after only 8 months.
achilleaslazarides@yahoo.co.uk - 30 Aug 2006 22:40 GMT
> I've heard of that...I think it's just too much signal gain at high ISO
> settings in dark shots. Lower the ISO to a more appropriate setting.

It's because of heat coming from electronic circuits near the sensor.
Not entirely surprising after an exposure of 3 minutes at ISO 1600.

It is removed, as you say, by dark frame subtraction.

> You should already know this, but those are called "hot pixels" and it's
> actually normal. The longer the exposure time the more hot pixels will
[quoted text clipped - 16 lines]
> The only thing of concern is the dead pixels. You shouldn't have that
> many after only 8 months.
Bill - 30 Aug 2006 22:48 GMT
>> I've heard of that...I think it's just too much signal gain at high ISO
>> settings in dark shots. Lower the ISO to a more appropriate setting.
>
>It's because of heat coming from electronic circuits near the sensor.
>Not entirely surprising after an exposure of 3 minutes at ISO 1600.

Oh...so cooling the sensor would fix it, like with an icecube?

But...how do I get the damn icecube inside the camera. I tried putting
it inside the sensor chamber, but then it blocks some of the light. I
shoved one in the battery slot, but then the camera don't work.

I even tried using the blender to chop up the icecube and shove the
little bits into the CF card slot, but still no good.

What am I doing wrong???

:-D
Buy_Sell - 31 Aug 2006 00:52 GMT
A peltier device and filtered cool air circulation would do the trick.
Might help keep the dust out of your camera as well.  Serious
telescopes are using cooling systems to fix this exact problem.

---------------

> >> I've heard of that...I think it's just too much signal gain at high ISO
> >> settings in dark shots. Lower the ISO to a more appropriate setting.
[quoted text clipped - 14 lines]
>
> :-D
achilleaslazarides@yahoo.co.uk - 31 Aug 2006 01:33 GMT
> >> I've heard of that...I think it's just too much signal gain at high ISO
> >> settings in dark shots. Lower the ISO to a more appropriate setting.
[quoted text clipped - 12 lines]
>
> What am I doing wrong???

One of these should do the trick:
http://atlas-magnet.web.cern.ch/atlas-magnet/cryo/gallery/photos/pump/

:)
achilleaslazarides@yahoo.co.uk - 31 Aug 2006 01:35 GMT
achilleaslazari...@yahoo.co.uk wrote:

> > >> I've heard of that...I think it's just too much signal gain at high ISO
> > >> settings in dark shots. Lower the ISO to a more appropriate setting.
[quoted text clipped - 12 lines]
> >
> > What am I doing wrong???

Laser cooling would also work, but the equipment may be somewhat less
than portable.
Thomas T. Veldhouse - 31 Aug 2006 13:34 GMT
> Laser cooling would also work, but the equipment may be somewhat less
> than portable.

And it wouldn't run well on those puny LiIon batteries ;-)

Signature

Thomas T. Veldhouse
Key Fingerprint: 2DB9 813F F510 82C2 E1AE  34D0 D69D 1EDC D5EC AED1

Bill - 31 Aug 2006 04:11 GMT
>> >It's because of heat coming from electronic circuits near the sensor.
>> >Not entirely surprising after an exposure of 3 minutes at ISO 1600.
[quoted text clipped - 12 lines]
>One of these should do the trick:
>http://atlas-magnet.web.cern.ch/atlas-magnet/cryo/gallery/photos/pump/

Does Atlas make an adaptor for my camera?

:-)
cjcampbell - 01 Sep 2006 01:55 GMT
> >> I've heard of that...I think it's just too much signal gain at high ISO
> >> settings in dark shots. Lower the ISO to a more appropriate setting.
[quoted text clipped - 12 lines]
>
> What am I doing wrong???

I use liquid nitrogen batteries. They last longer than the Nikon
lithiums and they keep the whole camera cool. You can find them at any
hardware store near the superconducters and mag-lev garage door openers.
cjcampbell - 01 Sep 2006 09:08 GMT
> Hi all,
>
[quoted text clipped - 6 lines]
> month later I am finding more. Has anyone else experienced anything like
> this?

No. But most of us are beginning to question that your camera is the
problem.

> But the latest and greatest weirdness became apparent recently when I tried
> to do a longish exposure--about 3 minutes--of the African night sky. I was
> shocked to find that all four corners and the top of the frame were luminous
> pink--looking like light-struck film.

Yes. This is a huge improvement over earlier DSLRs, where the pink
fringing, as you call it, would have covered the whole frame in less
than a minute. Photoshop is also a very useful tool if you are
interested in making this noise worse.
noone@nospam.com - 01 Sep 2006 13:48 GMT
Thanks to all for this info. I guess it doesn't have to go back to Nikon
after all, except to have those new dead pixels remapped.

Toby
 
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