Hi
Sorry for repeating a thread but the last one went wrong...tried to include an image and apparently it was too large but it nneded to be large to fully appreciate the problem.
So the story is I got a new filter, a B+W neutral grey ND1000 (or ND110) and decided to try it out before going off to use it.
The result horrified me as it shows a lot of pixel holes and noise.I treid the same shot without the filter and it doesnt happen.
So some would say my camera doesnt like the filter but as a lot of people use the same filter why do I have a problem.The memory card is only a few months old and I havent had any problems with that before.
Is it the camera which is knackered.It is a Nikon D100 so it is not that old. 
Heres is a link to part of the image,a reasoanble large file but it does show the problem.
Help nneded urgently please.

http://www.landscape-images.co.uk/auwful.htm

Try shooting only in your native raw format  rather than Jpeg  and turn your Long exposure noise reduction to on in your preferences menu under the options via the menu..

I usually shoot in RAW,I only shot this in jpeg to get some ideas of the results.
Thanks for your help

Did you do anything to the picture before posting it? I.E. turn op the exposure? Or is this picture straight out of the cam? What ISO setting was is shot on and what was the exposure time?

@ejn;
Like 3DGuy said...we need some more information here.
Did you do any post processing?...if so, what?
What is the exif data?

A few points;

1. Long exposures tend to accentuate noise
2. High ISO accentuates noise
3. Bumping up the exposure after the fact (even in RAW) accentuates noise.

Do a quick test...take a 30 sec exposure at the same ISO and Fstop as the one with your ND1000.....EXCEPT leave the lens cap ON!  Do NOT Process the image...take a look at it...is it as noisy as the one with the lens cap off?

In saying all of this....I have routinely shot borealis, noctilucent cloud and nightime lightning images with my old D70 in excess of 30sec at up to ISO 400...NO noise reduction applied in cam.....absolutely NO noise of any kind is visible.

Further, I have friends who have done 20+ minute exposures with both the D200 and D300...they have come out clean!

So...something seems to be amiss here in your situation.....

My only other thought here is that you accidentally ordered the B+W "Swiss Cheese" filter instead of the ND1000......

Hi Gradient,
Thanks for the info I will try out your suggestions.
In the between time what on earth is a Swiis Cheese filter.
Thanks for the help.
Eddie

Hi gradient,
I took a 30 sec exposure at f22 with the lens cap on as you suggested.I have put a cropped sample of the image at the link below.This is just a crop..no post work.If the image is enlarged you can see the is a mass of noise in there.
I also tried changing the memory card......just in case but still get the noise.

http://www.landscape-images.co.uk/awful2.htm

I am not sure what I should be looking for in the EXIF files so I put them on the page as well.
Thanks for all the replies.....I have a dreadful feeling I am going to be told it's a camera fault. 

Out of curiosity I shot a few images at 1/60 at f22 with the lens cap on and took the images up to 400% and there was no sign of any noise or hot spots.
So it seems to be only happening on longer exposures but once agian any suggestions or answers would be greatly appreciated.

@ejn;
Re- "swiss cheese" filter....my poor attempt at a joke....because of all the "holes" in your image!

I had a look at your lens cap "on" test....Thanks for posting that....I guess it confirms a few things...first, the ND1000 is not the problem.  Secondly, your test at 1/60 and F22 coming out "clean" confirms that your cam seems to be operating normally in common shooting situations.

Two things could be in play here...first and most likely is random noise....the way around that is to turn NR on in cam.  The second could be "hot" or "stuck" pixels....they always show up at the SAME location on your sensor...all sensors have these to some degree ( In fact all manufacturers map them out at the factory....but some may develop over time)...and they are more pronounced with long exposures.  You will need to compare the locations with several images to see if they are always showing up at the same location. 
If they show up in "normal" shooting conditions...they become a pain...and will require cloning out...or Re-mapping by Nikon.  Your 1/60 test shows that they are not a problem for most of your shooting situations.

If you find any "hot" pixels...here is a link to a freeware utility that will help remove them along with any "hot strips" you  may be experiencing....
http://www.pixelfixer.org/

I checked...it has support for the D100.

There is also other software available on the interent that will update the internal remapping of the D100...I won't post this as it is intrusive and if done improperly can damage your cam

Again, I can't speak for the D100....but my experience with the D70 at 30 sec long exposures up to ISO 400 shows NO noise of any kind....so, what you are seeing is unacceptable, in my mind.

Perhaps, a new D300 is calling out your name...LOL!

Hope this helps you out a bit...

Hi gradient,
Thanks for your time and your help.Puts my mind at rest even though I would still have to convince the wife about the D300.
In my own stupidity I tried google for the "Swiss Cheese" filter....didnt see that one coming :-)
I did consider in the end it was a joke about the holes but having a good sence of humour I had to smile at it.
Thnks for the link for the pixelfixer...I am one of those guys who dreads the thought of doing anything to the camera......my feelings with stuff like that is that if it can go wrong it probadly will.
I am off for a weeks holiday soon so wont do anything to the camera until after that.
Once agian thanks for your time and valuable input.
Eddie

@ejn;
The pixelfixer program does NOT touch the cam....it will analyze and fix your RAW images....so...it is safe to use.  It analyzes your RAW data...have a peek, it is actually not too bad a prog.

The OTHER prog I mentioned is the one that writes to the cam...I purposely did not put up that link ....because it is the one that could cause camera problems if not used properly.

To summarize....give pixelfixer a try.....it's free...it's safe!

Have a good holiday...BTW, don't tell your wife that the D300 was my idea.....

Hi Gradient,
Thanks for the comforting info.
I have downloaded pixelfixer and will give it a try.Got the family and grandkids with us at the moment so not going to get much peace to try it out....dont want the grandkids learning new words if something goes wrong :-)
I will give it a try when peace returns to the house.
Now would I tell the wife the D300 was not my idea :-)
Thanks once again...learnt a lot from this link so thanks to all the guys.
Eddie