How to reduce visible noise at higher ISO?

Please excuse the sound of the stupid question, but I'm still trying to understand how to use higher ISOs.

All of the threads about how the new 40D handles noise has me a little bummed about my 30D. I shoot horse shows and rodeos at night and often, even with fast lenses, I'm forced to shoot at higher ISO.

Are there any particular camera settings that help reduce visible noise in my pictures? Or is it all taken care of during post processing like Noise Ninja, etc?

I understand that a flash will help, but I only have a 580 right now, and I'm still trying to fully understand how ISO functions, other that what I read/understood from "Understanding Exposure."

Outside of a flash...your best bet to not introduce noise is to shoot to the right of the histogram, otherwise known as making sure not to underexpose. Under-exposed images create more noise.

Like you mention, after the fact you can always use applications or plug-ins for Photoshop like Noise Ninja (which I use when needed).

cowboylife wrote in post #3976292
Please excuse the sound of the stupid question, but I'm still trying to understand how to use higher ISOs.

All of the threads about how the new 40D handles noise has me a little bummed about my 30D. I shoot horse shows and rodeos at night and often, even with fast lenses, I'm forced to shoot at higher ISO.

Are there any particular camera settings that help reduce visible noise in my pictures? Or is it all taken care of during post processing like Noise Ninja, etc?

I understand that a flash will help, but I only have a 580 right now, and I'm still trying to fully understand how ISO functions, other that what I read/understood from "Understanding Exposure."

Check out the other thread about 30D Vs. 40D noise, there isnt a difference, so dont be 'bummed'

I use my 30D for weddings, so a good portion of my day is spent at ISO800, 1600 and 3200 and they're all useable.

Not knowing your expertise level, I will start from a simple level, so forgive me if it is too elementary.

My impression is that you are not completely sure about digital ISO and its relationship to noise. If you are familiar with film photography, then you probably know about the various ISO ratings seen on packages of film and that the numbers relate to the film's sensitivity to light. You also probably know that high-speed film (high ISO) has a much more pronounced grain than normal speed film and it is the grain that is responsible for most of the noisy image.

Even though digital photography uses electronic sensors, noise is just as much of an issue as it is with chemistry based film. The source of the noise is different, but it is still an inescapable fact of life. All electronic devices produce noise. Normally, it is insignificant enough to not be noticeable. With the sensors used in digital cameras, however, the amount of light that each sensor element detects is very small and so the output has to be amplified considerably to have a usable output (Just imagine how small each of the ten million sensors on a 14 by 22 millimeter chip is and yo can appreciate the small amount of light that is being detected by each sensor element). When we amplify the signal, the noise gets amplified right along with the useful part of the signal.

In digital photography, the sensor array emulates not just a single ISO value as in the case of a roll of film, but a wide range of ISO speeds from 100 up to 1600 or 3200. What this means to you when shooting at ISO 1600 is that the camera is amplify the sensor output 16 times as much as it is being amplified at ISO 100. I your camera also has ISO 3200, this means that the noise will be twice as great as it is at 1600, or 32 times as great as the noise at ISO 100.

You can see the importance of developing a sensor array that has very low noise output. This is an evolutionary process -- the newest cameras have sensors that are much less noisy than those developed just a few years ago. The same thing can be said about future developments in sensor technology. The bottom line then would be that the sensor that you have on your current camera reflects the state of the art at the time that it was released on the market and it is not going to get any better. Whatever you have is great -- until something new comes along with better performance. Your options seem to be: Get a 40D or be satisfied with the camera that you have . Funny how that works.