A lot of people associate noise with unwanted sound. Some people like me also call unwanted/unintended/undesirable pixels of a photo to be noise.
Here is the data spitted out by dcraw commandline utility.
Filename: Pictures/2008-01-16–06.53.37/dsc_2397.nef
Timestamp: Tue Jan 15 19:31:44 2008
Camera: NIKON D100
ISO speed: 320
Shutter: 10.0 sec
Aperture: f/29.0
Focal length: 70.0 mm
Embedded ICC profile: no
Number of raw images: 1
Thumb size: 570 x 375
Full size: 3040 x 2024
Image size: 3037 x 2024
Output size: 3037 x 2024
Raw colors: 3
Filter pattern: GRBGGRBGGRBGGRBG
Daylight multipliers: 2.614252 0.930754 1.396616
Camera multipliers: 360.000000 256.000000 724.000000 256.000000
Now, I don’t claim to know what every piece of information printed above means. But the ISO setting tells me that 320 is not a very high light sensitive setting.
But here is the detail:
That photo was at 25% magnification of the original. The 100% cropped picture is below:
And this is just at 100%. I wonder what happens at higher magnification or at higher ISO. Would be a good thing for study, wouldn’t it. There is of course one piece of detail that may be relevant. The white balance I used is of filament bulb. But the lamps are of “warm white” compact fluorescent! Are they somewhat the same? Hmmm….
