Nikon D100 long exposures - Help!

Hi,

I just tried some long (8sec-30sec) long exposures with my D100 and am very
disappointed with and confused by the results.

On a number of the images (especially those at 15 and 30 seconds) there are
a TON of specular highlights (blown out pixels?) ALL OVER the image. My
D100 works perfectly otherwise, both before and after this particular shoot.
It's not an issue of dust on the sensor.

Is there something about long exposures that digital SLR's don't do well
with?

TIA---

Anonymous wrote:
Hi,

I just tried some long (8sec-30sec) long exposures with my D100 and
am very disappointed with and confused by the results.

On a number of the images (especially those at 15 and 30 seconds)
there are a TON of specular highlights (blown out pixels?) ALL OVER
the image. My D100 works perfectly otherwise, both before and after
this particular shoot. It's not an issue of dust on the sensor.

Is there something about long exposures that digital SLR's don't do
well with?

There is a problem with "dark current" causing these speckles. Most
cameras have a "noise reduction" or "dark frame subtraction" mode to
compensate for this. It may double the total exposure time, though. Read
your manual.

Cheers,
David

Anonymous wrote:
Hi,

I just tried some long (8sec-30sec) long exposures with my D100 and
am very disappointed with and confused by the results.

On a number of the images (especially those at 15 and 30 seconds)
there are a TON of specular highlights (blown out pixels?) ALL OVER
the image. My D100 works perfectly otherwise, both before and after
this particular shoot. It's not an issue of dust on the sensor.

Is there something about long exposures that digital SLR's don't do
well with?

There is a problem with "dark current" causing these speckles. Most
cameras have a "noise reduction" or "dark frame subtraction" mode to
compensate for this. It may double the total exposure time, though. Read
your manual.

Cheers,
David

Anonymous wrote:
Hi,

I just tried some long (8sec-30sec) long exposures with my D100 and
am very disappointed with and confused by the results.

On a number of the images (especially those at 15 and 30 seconds)
there are a TON of specular highlights (blown out pixels?) ALL OVER
the image. My D100 works perfectly otherwise, both before and after
this particular shoot. It's not an issue of dust on the sensor.

Is there something about long exposures that digital SLR's don't do
well with?

There is a problem with "dark current" causing these speckles. Most
cameras have a "noise reduction" or "dark frame subtraction" mode to
compensate for this. It may double the total exposure time, though. Read
your manual.

Cheers,
David

Anonymous wrote:


Is there something about long exposures that digital SLR's don't do well
with?

Yes. You can enable dark-frame subtraction noise reduction to reduce the
noise; it'll be called "long exposure noise reduction" in the menu, and
will result in processing time after each shot equal to the exposure time
of that shot (during which you will not be able to take another shot).
It does an excellent job, since this kind of noise is far easier to clean
up than the random sensor noise we all know and love.

--
Jeremy |

Anonymous wrote:


Is there something about long exposures that digital SLR's don't do well
with?

Yes. You can enable dark-frame subtraction noise reduction to reduce the
noise; it'll be called "long exposure noise reduction" in the menu, and
will result in processing time after each shot equal to the exposure time
of that shot (during which you will not be able to take another shot).
It does an excellent job, since this kind of noise is far easier to clean
up than the random sensor noise we all know and love.

--
Jeremy |

Jeremy,

I'm not sure I follow you. I double checked the D100 manual and under "Long
Time Exposures" all it says is to turn on Custom Setting 4 which increases
exposure time (similar to reciprocity failure in traditional film). It says
nothing about reducing the "speckles" which come with long exposures.

Can you clarify your post below?

Thanks---


"Jeremy Nixon" wrote in message
...
Anonymous wrote:


Is there something about long exposures that digital SLR's don't do well
with?

Yes. You can enable dark-frame subtraction noise reduction to reduce the
noise; it'll be called "long exposure noise reduction" in the menu, and
will result in processing time after each shot equal to the exposure time
of that shot (during which you will not be able to take another shot).
It does an excellent job, since this kind of noise is far easier to clean
up than the random sensor noise we all know and love.

--
Jeremy |

Jeremy,

I'm not sure I follow you. I double checked the D100 manual and under "Long
Time Exposures" all it says is to turn on Custom Setting 4 which increases
exposure time (similar to reciprocity failure in traditional film). It says
nothing about reducing the "speckles" which come with long exposures.

Can you clarify your post below?

Thanks---


"Jeremy Nixon" wrote in message
...
Anonymous wrote:


Is there something about long exposures that digital SLR's don't do well
with?

Yes. You can enable dark-frame subtraction noise reduction to reduce the
noise; it'll be called "long exposure noise reduction" in the menu, and
will result in processing time after each shot equal to the exposure time
of that shot (during which you will not be able to take another shot).
It does an excellent job, since this kind of noise is far easier to clean
up than the random sensor noise we all know and love.

--
Jeremy |

Anonymous wrote:

I'm not sure I follow you. I double checked the D100 manual and under "Long
Time Exposures" all it says is to turn on Custom Setting 4 which increases
exposure time (similar to reciprocity failure in traditional film). It says
nothing about reducing the "speckles" which come with long exposures.

I don't have a D100, so I don't know what its Custom Setting 4 is. On the
D70, it's the second option in the shooting menu, labeled "Long exp. NR"; it's
not in the Custom Settings menu.

I've no idea what it's getting at with increasing exposure time; there is no
reciprocity failure with digital. And the D70's Custom Setting 4 is to enable
the autofocus assist light, which I assume isn't what you're referring to.

--
Jeremy |

Anonymous wrote:

I'm not sure I follow you. I double checked the D100 manual and under "Long
Time Exposures" all it says is to turn on Custom Setting 4 which increases
exposure time (similar to reciprocity failure in traditional film). It says
nothing about reducing the "speckles" which come with long exposures.

I don't have a D100, so I don't know what its Custom Setting 4 is. On the
D70, it's the second option in the shooting menu, labeled "Long exp. NR"; it's
not in the Custom Settings menu.

I've no idea what it's getting at with increasing exposure time; there is no
reciprocity failure with digital. And the D70's Custom Setting 4 is to enable
the autofocus assist light, which I assume isn't what you're referring to.

--
Jeremy |