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Old May 9, 2006, 12:42 AM   #1
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I tried different lenses and these dots still appear on the exact same spot. I already blew and brush the dust in ccd. I don't know whats the problem, I hope its not a bad CCd.. The dots are more visible on dark spots. I got a nikon d100.

This photo was edited in photoshop using auto levels to make the dots more visible. Please help, I'm getting frustrated with this...
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Old May 9, 2006, 12:53 AM   #2
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I'm sorry to say this, but it looks like "hot pixel", "dead CCD pixel", or whatever else people call it: Google Search


How old is this camera? And how many actuations does it have?

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Old May 9, 2006, 7:55 AM   #3
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reynaldo wrote:
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This photo was edited in photoshop using auto levels to make the dots more visible. Please help, I'm getting frustrated with this...
I can tell. It looks like it was underexposed and brightened because the shutter wasn't left open long enough.

How long was the exposure?

Do these show up in correctly exposed images in typical lighting with shutter speeds faster than 1 second?

Hot Pixels are normal on longer exposures. Your camera has a built in dark frame noise reduction system to map them out.

It works on photos taken longer than 1 second (where hot pixels usually show up). The way it works is by taking two photos. The first photo is of your subject. Then the camera automatically takes a second image using the same settings with the shutter closed.

The camera then notes the positions of any hot pixels in the "dark frame" (second) exposure, and maps them out of the actual exposure by interpolating values from surrounding pixels to replace the hot ones. It knows where to find them because the dark frame exposure was taken at the same time, using the same settings, with the camera at the same temperature. In most cases the hot pixel locations will be the same in both images using this technique. But, the longer the exposure, the greater the chance it will miss some of them.

Menu Choice 4 under your Custom Settings menu is used to enable or disable Noise Reduction on long exposures (1 second or longer). Turn it on. It's entire purpose is to get rid of hot pixels on long exposures.

If you have a pixel that is always hot (bright), even on shorter exposures in good light, then it's referred to as a "Stuck" pixel. The Long Exposure NR feature won't help for that. A pixel that's always dark is referred to as a dead pixel.

In most cases, when a camera develops a stuck pixel, a trip back to the manufacturer is needed. The manufacturer then updates a bad pixel table in EEPROM. When a photo is taken the image processing automatically checks the camera's bad pixel table and maps the pixel out (replaces it with values determined from adjacent pixels using sophisticated interpolation algorithms.

Some cameras allow the user to perform a bad pixel map themselves (a number of Olympus models have a menu choice that calls a procedure to locate and map out bad pixels). Some cameras do this automatically (KM DSLR models have an undocumented feature that checks and maps out bad pixels on a monthly basis that you can force by setting the date up one month if you don't want to wait after you see a bad one).

With most Nikon models, a trip back to the manufacturer is needed. But, with the D100 you can find software to do it yourself.

http://www.mathiaspohl.de/dx/remove-dead-pixels-nikon

Use at your own risk.

Here is the menu choice you need to turn on for the camera to fix the ones that show up on long exposures:

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Old May 9, 2006, 12:57 PM   #4
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I actually got this used so I don't know how old is it. But when I got it, everthing looks actually new, the buttons, accessories, and even the battery life is great. the dots are not really noticeable when I don't zoom in the picture, I can always edit that in photoshop. I was just curious at what those dots are.
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Old May 9, 2006, 1:00 PM   #5
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These dots actually appear on all pictures, underexposed or overexposed. Very noticeable when in black background or dark pictures. I don't think they are because of the noise produced because the dots are at the same place on all pictures.
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Old May 9, 2006, 1:20 PM   #6
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4 main choices:

1. Send it back to Nikon and let them map out the bad pixels. Chances are, it will run you around $200 (provided it's not a gray market camera and was intended for sale in the U.S., since Nikon USA will refuse to service one if it was intended for sale elsewhere, and some vendors have been known to sell gray market imports).

Other regional Nikon distributors (for example Nikon Canada) have the same policy. The camera must have been intended for sale in the region you live in before they will service one.

2. Use the utility I mentioned and map them out yourself (this is what I'd do if it were my D100). But, do that at your own risk.

3. Remove them from images using software (and there are more automated ways to go about it).

4. Leave them in the photos. ;-)

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Old May 9, 2006, 1:22 PM   #7
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thanks jim! I actually viewed the url you gave me and requested for the software. Thanks for the help, saved me some time in figuring out what the problem is. Thanks
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Old May 11, 2006, 11:57 AM   #8
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heres an alternate fix in photoshop



zoom way in select each white dot put them on layer

in filters menu under other

choose minimum

:|then you can change the layer opacity if too darkened
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Old May 11, 2006, 12:26 PM   #9
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Thanks for the reply. It's actually hard to view all the those dead pixels in photoshop unless you zoom and view the whole area. I wanted to fix this on my camera. I got the program Q50imageadjust for nikon d100 to remove and remap these dead pixels. Worked great! if anybody wants it, just email me. thanks
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Old May 11, 2006, 10:30 PM   #10
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I had a camera that did this. it was dust on the ccd. You could clone them out in Photoshop or any other imageing program.
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