I'm having noise problems in my DSLR photos?

I have a nikon D40 and my ISO is set to 100. But whenever i take a dark shot like at night or during thick fog, I get a whole bunch of noise. These arent shots that need longer exposure either… Is there something else i can do to reduce noise?

Added (1). Nikon D60**
it IS set to 100
i was shooting at night in a lit parking lot so an exposure any longer than 1/10 would have had all the street lights blown out…

If you take a shot at night, of course it will need a longer exposure.

There's a certain amount of noise generated during long shots like shooting at night.

Your camera has an ISO range of 200 - 1600. No 100 ISO. It also has an AUTO ISO setting and my guess is that you may have your camera set to AUTO ISO

The last generation of entry level cameras (D3200) that replaced the D40, certainly out performs the D40 at high ISO.

http://www.dxomark.com/...eBookmarks

Noise can be reduced using Noise Reduction (NR). Look on page 73 of your user manual. The same page shows you what ISO settings are available for your camera.

Can you post an example on Flickr with full exif?

Difficult to say without seeing the images but I too find it difficult to believe that you have taken shots at night at ISO100 AND short exposure.

Another thought - that camera is 5 or 6 yrs old - when did you last have the sensor cleaned?

Use your histogram exposure and try to stay on the right side but not too far because you'll hit the wall and the white will be blown out, it should help you reduce the noise a little even if you have to lower the exposure in post processing, doing it the other way will increase the noise.

Make sure your noise reduction is turn on.

The noise we see on our computer screen rarely appear on print, to show on a print the noise as to be extreme.

If your taking shots in low light and the shutter speed is high then your camera is selecting a high ISO which will increase noise dramatically. Take your camera out of Auto ISO.

Set the ISO as low as you can (200 on a Nikon D40), use Aperture Priority Mode (A or Av), set the aperture to a mid setting (f5.6 or so), half press the shutter and the camera will tell you the shutter speed it has to set to get a decent exposure, shutter speeds as slow as 1/4 or a 1/2 of a second aren't unusual in low light, which means the use of a tripod to eliminate camera shake.

You can turn on NR (noise reduction for long exposures), this will take a second frame at the same shutter duration with the shutter closed and records the sensor noise. This is subtracted from the first exposure reducing noise.

The only real way to get rid of noise is not to shoot in low light which sounds crazy, but you'll see Pro photographers always use flash or other lighting to increase the light levels in the image, this will dramatically reduce or even eliminate noise, you need much more light than you think.

They will shoot in Raw and adjust exposure in Post Processing to get the effect they want from a bright image, this way they get a low key (dark) picture without any noise.

It has to be said that sensor technology has moved on in leaps and bounds since the D40 was released, it never was a good camera in low light, but you work with what you've got.

You iso is 200 or higher. The d40 doesn't go to 100.turn on noise reduction in your camera settings.use a tripod and longer exposure if you need too.

You can't use the same exposure settings for both street lights AND the dark. All camera sensors and film are limited to a certain dynamic range. You have a choice. Either "blow out" the street lights and get a properly exposed subject in the dark, or properly expose for the street lights but get dark subject area.

As far as noise goes, that is odd if you are only using isO 100. I wonder if the fog is making it look like noise.