digital noise

I shoot with a d100 and I have been having trouble with noise in my pictures. The lens that is causing the problem is a 35-70mm 3.3-4.5 lens... not the best and it's been around for a bit, however it takes great pics sometimes and then other times there is a lot of noise.
For example, I set up my lights and did some pics of Emilie one night and then the next night I set my lights up again, in the same set-up (eh, close enough) and did some pics of a couple and their baby. The shots of the couple came out rather noisy compared to Emilie's. Emilie's were perfectly clear and the couple's noisy.
I also use the uncompressed raw format for saving photos.
Has anyone else had a problem with this?
And does anyone know what is causing this?
Thanks for your time and help.

Did you have the camera on auto? Did you let it pick ISOs automatically? The lens is not the issue, no lens can increase or decrease noise, it's all in your ISO choise. Keep it at 200 to minimize the noise, turn in-camera sharpening off, and make sure your exposure is right. Any raising of the levels later on will bring out the dark channel noise.

Keep in ind that the RAW files bring out more detail, and therefore more noise. I never found it objectionable at ISO 200, it sounds to me like you might have it set higher. The higher the ISO, the noisier the shots. That said though, the D100 is very capable of beautiful 8x10 at ISO 1600.

Hmm... I do everything manually on my camera, from the white balance to the iso setting to the shutter speed and aperture settings... the only thing auto is the focus and only sometimes. Hmm... I'm wondering if maybe my exposure was a bit off...
I was concerned because my camera and I took a nasty spill down the stairs a little while ago and while I protected it as best as I could ( sacrifice for the safety of the camera *smile*) I know it got bumped around a little and I was afraid that I had damaged it...
I think, however that my exposure may have been off somewhat and that is what caused the problem. I will pay closer attention next time and see if that is indeed what is happening. Thanks so much for the reply Sebastian... I was very frustrated with this and I appreciate the help.

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Originally Posted by darkrainfall

Hmm... I do everything manually on my camera, from the white balance to the iso setting to the shutter speed and aperture settings... the only thing auto is the focus and only sometimes. Hmm... I'm wondering if maybe my exposure was a bit off...
I was concerned because my camera and I took a nasty spill down the stairs a little while ago and while I protected it as best as I could ( sacrifice for the safety of the camera *smile*) I know it got bumped around a little and I was afraid that I had damaged it...
I think, however that my exposure may have been off somewhat and that is what caused the problem. I will pay closer attention next time and see if that is indeed what is happening. Thanks so much for the reply Sebastian... I was very frustrated with this and I appreciate the help.

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You're welcome. In regards to damage causing more noise, highly unlikely. Digital is either on or off, the image either is there or it isn't. Damage would not cause increase in noise, it would prevent images from appearing altogether, would cause parts of images to be garbled or missing, or would prevent the camera from functioning altogether. There have been issues in the past with faulty cicuitry causing noise in images, but that was mostly poor shielding or wrong spec parts used on the boards where the processing takes place, introducing interference similar to what you see on a TV screen if you vacuum too close to it. The faulty part would interfere with the processing adding electrical signals into the conversion process before the analog CCD signal was converted to the digital file, creating patterns or banding.

IF the fall cause a switch to become damaged, not allowing you to change the ISO setting, that would be different. But damage to a camera will display itself in many forms that would be much more obvious than a slight increase in noise.

Wait, I just realized that the camer fell WITH YOU! Were you ok?? Here I am again with my blinders on, going on about the camera when you could have been seriosuly hurt...moron. :D

Hmmm... I guess I still have a lot to learn about the internals of the dig camera... thanks for explaining that to me.

*smile* I was mostly okay... I was in heels and all that because I was headed to an awards banquet to photograph and apparently the steps were a bit icy... I'm pretty tough though, and my first thought was to my camera as well... so don't feel bad about that... and I sustained only a few bruises and scratches... oh... and I couldn't move the next day... but at least my camera was safe *smile*

Could someone please show me what noise is?

Also is there a place on this forum to post sales?

Thanks

It's the digital version of grain, it's the color blotches and patterns that develop when ISO values are boosted.

THere is a classifieds link at the top fo the page.

Just looking at the forum for the first time,

Try Neat Image from this site, you can get the free one from the Download page, it will put an icon the desktop for you. Just import your picture and the program will take a noise selection and smooth out the whole picture for you and save it as a jpeg to any folder you specify. Give it a try I think it will help you a lot. Ideal for portraits and people pictures.

http://www.neatimage.com/index.html

Hope it helps