D1H white dots everywhere.

[kev]

When I shoot in low level light with long exposure. 10+ seconds I

get white looking dots all over the image. It isnt noise at least I

dint think it is.

 

Even if I change lenses I get the exact same white marks everywhere.

I did a test of differtent locations with long exposure and the white

marks are in the same place every time. The lenses are clean because

if I shot with film F5 I do not get any problems like this at all.

 

Attached are some examples. If you look in the right lower you will

see the exact same white dots/lines/etc... in the exact same location.

 

I really need help as Nikon has not replied and I need to know what

to do.

 

Is this something I have to just deal with or can this be fixed or ???

 

I just bought the camera and I am stumped.

 

Image 1;

http://www.photo.net/photo/1540443&size=lg

 

Image 2;

http://www.photo.net/photo/1540444&size=lg

 

The white dots are in the exact same place.

 

 

Thanks,

 

Kevin

[craig_bridge]

The D1H wasn't designed for long exposures. Newer in camera methods involve taking a second picture of the back of the shutter and subtracting out the hot pixels. You can try a similar approach by putting on a lens cap and taking a picture of it with the same time length to get a hot pixel intensity map and subtracting in post processing.

[jbq]

Those are called hot pixels, and are (if I remember correctly) places that get hot on the CCD during long exposure, to the point of emitting infrared radiation, which CCD are extremely sensitive to.

 

As a camera designed for very high speed and high sensitivity, I'm not surprised that the D1H has a lot of those. I think I read somewhere that the D100 did slightly better for long exposures. Hige-end cameras (e.g. Sinar back) are actively cooled to reduce such effects.

[jeff_kelley]

The Fuji S2 and some of the newer Canon digital SLRs work with 30 second and longer exposures but they were designed to do so.

 

The only thing you can do about long exposures on the D1 series is post processing in Photoshop....

[aardvarko]

<p>Actually, "hot" pixels are elements of the CCD/CMOS that have a defective transistor, causing them to always report 100% brightness. "Dead" pixels are the inverse - elements that are always 0% brightness. For example, my CP995 has two hot pixels, one magenta and one green <i>(good ol' Nikon's too good for a Bayer array ;-) )</i>; they show up even in 1/500s, F11 shots on a sunny day. </p>

<p>

Have you examined the white spots at 100% zoom in your image editing application? My money's on them not actually being white.

</p><p>

You may have luck with the following post-processing trick...

<br><br>

1. with the lens cap on, take a picture at the same shutter speed as the shot you are trying to fix<br>

2. open the lens cap picture in Photoshop/PSP and invert it<br>

3. drag the lens-cap-picture on top of your real photograph and set its layer blending mode to "Multiply"<br>

</p><p>

Or, if my hunch is correct and your noise isn't white, but R/G/B or Y/M/G/C, here's a trick for lessening it...

<br><br>

1. duplicate the Background layer of your picture

<br>2. Gaussian Blur, 8-15px

<br>3. change blending mode of blurred layer to Color

</p><p>

To restore color detail for crisp edges, just create a Layer Mask for the top (blurred) layer and paint away with black.