Understanding Noise

Hello.

I am new to DSLR photography and while I have been enjoying it, often when I get home to upload images to my computer I realize how much noise most of them have in them.

I understand noise has to do with exposure, but am not entirely sure which aperture to shutter speed values increase or decrease noise.

I also understand noise has alot to do with ISO speeds, and therefore I always shoot in ISO 100 on RAW format (unless I'm just going for a capture or info) but still tend to get alot of it - even with noise reduction turned on in my camera's menu setting and having the camera stablized.

Sometimes I manage to avoid the chromatic noise but end up with alot of the translucent luma noise, which ruins the details and smoothness of my shots.

Just seems wierd that after over 1000 dollars spent I'm still having the same frustration that made me switch from my last P&S after the damn thing ruined all my Las Vegas vacation pictures with that ugly chroma noise.

Current gear: XSi/450D - Tamron 17-50 2.8 - Canon 18-55mm IS USM

Thanks for looking

Can you post an image? It'll help us better understand what's going on.

Noise comes from amplifying the charge on the photo sensor so the higher your ISO the worse the noise. You can also get noisy pictures by underexposing (at any ISO setting) then adjusting the exposure up in post processing. So whatever ISO you choose, and particularly in the higher ISO settings, work to keep your exposure histogram to the right side of the scale.

Yes, a correct exposure will go a long way towards minimizing noise.
But keep in mind, keeping that needle in the middle doesn't always mean correct exposure. If you are going to miss, try to miss to the right.

And as other have mentioned already, let's see some samples!

Roach711 wrote in post #7653053
Noise comes from amplifying the charge on the photo sensor so the higher your ISO the worse the noise. You can also get noisy pictures by underexposing (at any ISO setting) then adjusting the exposure up in post processing. So whatever ISO you choose, and particularly in the higher ISO settings, work to keep your exposure histogram to the right side of the scale.

OK. So it's probably better to shoot a little brighter than I'd like. Maybe it's because I tend to shoot to the left of the 0? I should not that.

nicksan wrote in post #7653119
Yes, a correct exposure will go a long way towards minimizing noise.
But keep in mind, keeping that needle in the middle doesn't always mean correct exposure. If you are going to miss, try to miss to the right.

And as other have mentioned already, let's see some samples!

Well, I don't really understand how to post pictures on this forum. I keep getting broken image links.

Yeah, that's a recipe for noise right there.
Shoot to the right if you can, and make sure you get the exposure correct...and not necessarily getting the needle in the middle!

deming wrote in post #7653128
OK. So it's probably better to shoot a little brighter than I'd like. Maybe it's because I tend to shoot to the left of the 0? I should not that.

https://photography-on-the.net/forum/showthre​ad.php?t=51049

deming wrote in post #7653140
Well, I don't really understand how to post pictures on this forum. I keep getting broken image links.

You can post them as attachments. They have to be 1024 at the longest and 150 kb for jpg.

So even on ISO 100 in RAW format it will still do that? Some of the images are noisy right out the camera though.

err.

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

Looks underexposed.
Did you pull the exposure up in post?

deming wrote in post #7653334
err.

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

You should have some leeway with ISO 100 in terms of noise, but generally speaking underexposing a shot is a recipe for noise.

deming wrote in post #7653200
So even on ISO 100 in RAW format it will still do that? Some of the images are noisy right out the camera though.

nicksan wrote in post #7653429
Looks underexposed.
Did you pull the exposure up in post?

No this is unedited. As you can see it's pretty harsh though. The RAW file of course isn't as bad but it's still bad.

I have some that I overexposed just now, I'll upload one in a sec.