Re: D200 owners, pls. do this test for me (and yourselves)


I don't have a D200 (yet) and can't comment on the blooming, but I do
have a D70 and I can tell you that the red, blue white pixels showing
up at 3 minutes / ISO 1600 are normal for every digital camera. This
is the noise and the difference in individual pixel sensitivity that
every sensor has and that starts showing on long exposures and higher
sensitivity. The blue/red pixels are so-called "hot pixels" (as
opposed to dead pixels). Pushing it to ISO 1600 means that your pixel
response is amplified more, which makes them show up brighter than
others - about the same as cranking up your stereo to +20db without
an input signal. Even though you have a perfect stereo system, you
will still hear white noise at that setting! 3 minutes at 1600 is at
the extreme end of what the camera (and its sensor) can do.

The warmer it is, by the way, the more you will see that effect
(Africa!). Just for kicks, I recommend that you do the same with your
camera on a very cold day (read: in the refrigerator [inside a plastic
bag, of course, to avoid condensation - and leave it in there until
warmed up again]). You will likely notice much less of that noise
(semiconductors behave better at lower temperatures - in contrast to
your battery, though).

As for the dead pixels: 20+ sounds excessive and more showing up is
not a good quality sign. I think I will wait until the back-log is
diminished... However, Nikon has a feature to map the dead pixels,
which basically turns them off and interpolates between neighboring
pixels. That way, you at least don't have white spots showing up,
needing to be edited out.

Post-exposure noise reduction also helps, especially with the hot
pixels.

Good luck!

AW

On 1 Sep 2006 07:31:02 -0500, noone@xxxxxxxxxx wrote:

Hi all,

I tried sending this beofre but I never saw it appear. Apologies if this is
a double post.

I've had my D200 for about eight months now. I love it, but it has been
plagued with a number of sensor problems.

First was the long banding. That was fixed (I believe they replaced the
sensor, although the service report only said "tiny parts replaced"). Then
pixels started dying. First there were three; a month later I noticed about
20 new ones--in some situations the small white crosses turned into red and
blue squares. Now a month later I am noticing some new ones.

But the big surprise came when I tried to do a long exposure (~3 minutes) of
the African night sky. On viewing the four corners and top edge of the frame
bloomed with pink luminosity, looking something like light-struck film. In
addition there were scores of seemingly-dead pixels speckling the whole
frame in white, red and blue. But these pixels were not dead, in shorter
exposures they behaved normally, but as the exposure time increased more and
more of them blew out. Likewise the pink blooming was undetectable at under
30 secs., becoming progressively worse as trhe exposure time increased.

Obviously the camer is going back to Nikon, but I am actually very curious
about whether these are common defects. They only became apparent in my case
in rather rare shooting conditions (long exposures). If anyone with a D200
is willing, I would ask you to do the following simple test: Put a body cap
on your camera and do a 3 minute exposure at ISO 1600 in a dark room (or put
an eyepiece cap on as well). If you have anything like the same problems as
mine they will be very obvious on preview--the blooming at full frame and
the pixel problems on either of the last two crop magnifications.

I would be very interested to hear what your experience is.

TIA,

Toby

please respond here or if you wish respond privately to kymarto (at-sign)
yahoo (dot) com

.

Relevant Pages

  • D200 owners, pls. do this test for me (and yourselves)
    ... pixels started dying. ... But the big surprise came when I tried to do a long exposure of ... On viewing the four corners and top edge of the frame ... I would ask you to do the following simple test: Put a body cap ...
    (rec.photo.digital.slr-systems)
  • Re: D200 owners, pls do a test for me (and for yourselves)
    ... but afterward pixels started dying. ... And the whole frame was studded ... more and more being "blown out" and luminescing as the exposure ... Go in a dark room, put a body cap on to stop any light ...
    (rec.photo.digital.slr-systems)
  • Re: D200 owners, pls do a test for me (and for yourselves)
    ... First I had three dead pixels remapped, ... shocked to find that all four corners and the top of the frame were luminous ... more and more being "blown out" and luminescing as the exposure lengthened. ... Go in a dark room, put a body cap on to stop any light from ...
    (rec.photo.digital.slr-systems)
  • D200 owners, pls do a test for me (and for yourselves)
    ... First I had three dead pixels remapped, ... shocked to find that all four corners and the top of the frame were luminous ... more and more being "blown out" and luminescing as the exposure lengthened. ... Go in a dark room, put a body cap on to stop any light from ...
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