noise in photos

[Kushka4paws]

A lot of comments to some pics is to much noise. This is going to be a stupid question BUT :oops: What does that exactly mean? Busy background or not 100% in focus?
Please help the dazed & confused! :shock:

[Roy W.]

Check this out: http://aquatic-photography.com/phpBB2/viewtopic.php?t=1575

At a high ISO level there is going to be noise in the picture!
Some cams more than others, DSLR`s are genious on this field!
Compacts is`nt!

Noise is grains in the whole pic making it unsharp..
Take a good look at the pics in the link and you`ll see what i mean 8)

[Nicholo]

High noise in digital images is the visible equivalet of "grain" in film cameras. Cheaper cameras (with cheaper sensors) will output more noise (spec. small differences in photodiode output) than the expensive sensors on dSLRs. Noise is most evident when people try to achieve faster shutter speeds (typically in low light conditions where the subject is moving or the camera cannot be kept motionless) by ramping up the ISO setting on the cam (akin to changing film speed in film cameras, although in digital cams, it's more appropriately referred to as a sensitivity setting). You get faster shutter speeds (hence reduced/eliminated motion blur from the fish, for example), but your noise increases as well. The sensor is trying to amplify the signal (i.e., light) but in the process, everything is amplified, including the noise. Thus, in aquarium photography, the optimal solution is not to increase the ISO, but to provide more light.

See these brief, simple articles for more (read: better) information:
Noise (http://www.dpreview.com/learn/?/Glossary/Digital_Imaging/Noise_01.htm)
ISO (http://www.dpreview.com/learn/?/Glossary/Digital_Imaging/Sensitivity_01.htm)

[Kushka4paws]

Thank you for the info I thought that might be it, but I just wanted to make sure! I appreciate it!