20D Noise reduction

[Loaded]

Got a few Q's for those in the know.

1. does it work in RAW?
2. If it does, does it substantaily reduce right time?

[AjP]

there are setting in Adobe RAW converter to reduse noise and luminance smoothing... something like this, just don't apply any sharpening when converting from RAW but if there are too much noise, you better use Noise Nija or Neat Image or something like thins

[drisley]

The Noise Reduction feature is a bit mislabelled.
In reality, it doesn't reduce noise on long exposures, but rather it reduces/eliminates hot pixels on long exposures. It does this by taking a second blank frame and subtracting from the first.
It takes exactly twice as long to do this. If you exposure is 10 seconds, it has to take a second 10 second blank exposure for subtraction. This feature only kicks in on exposures longer than 1 second (I believe).
And yes, it does work on RAW..

There is a comparison shown here (http://www.dpreview.com/reviews/canoneos20d/page21.asp) about a third of the way down the page.

[Benmok7]

Thanks Drisley, I asked the same question yesterday for the 350D but no one could give me an answer.

Have you tried using the noise reduction function? Do you think its worth using?

Thanks,
Ben

[drisley]

I wouldn't use the NR feature unless I was using a really long bulb exposore to keep hot pixels to a minimum. I also might use it for a 30 sec exposure at ISO1600.
But, I've done exposures at 30 sec at ISO's from 100 to 400, and they are almost silky smooth, and no apparent hot pixels.
I found no apparent difference in the amount of noise with the feature enabled, only the removal of hot pixels in the rare case they are present (like in conditions mentioned above).

[Benmok7]

I didn't know how the noise reduction work initially and tried it for an hour exposure. Boy I over did it that time :)
Thanks for the tip!

[drisley]

For an hour exposure, noise reduction might be a good idea because you may get alot of hot pixels.
However, it may be faster to remove them later with Photoshop's heal tool.

[Medic1]

I seem to get alot of noise with my 20D at 400ISO.....why is that? I thought the 20D was supposed to have good image quality at 400 with little noise.

Kind of along the same lines.......

[Joe R]

For exposures longer than 6-8 minutes you will get less noise by stacking. Take multiple exposures and pull them into Photoshop as one layered file with all the layers set to Lighten blending mode. The timer remote comes in handy here, allowing you to automatically set multiple exposures with a 1 second interval (especially important if there are stars in the photo).

I get a few hot pixels with the 6-8 minute exposures, but would rather just use the cloning tool to spot them instead of waiting an additional 6-8 minutes for noise reduction. Noise reduction may also effect sharpness - it's better handled in the computer instead of in the camera.

[BobbyC]

I seem to get alot of noise with my 20D at 400ISO.....why is that? I thought the 20D was supposed to have good image quality at 400 with little noise.

Kind of along the same lines.......

If you are using Adobe Raw to convert, that may be the problem. I have compared ISO400 and up shots with Adobe RAW (CS2), Breezebrowser, DPP and C1 and Adobe RAW is the worst by far, particularly at ISO 800 and above. Try it yourself, at 1600, Adobe RAW creates a horribly noisey file, that none of the others showed, it's like it adds noise. This for both the 10D and 20D.

The 20D is very smooth at 400, I've made 11x14's at 1600 that are very, very acceptable (Provided I use a converter other than PS Raw).

[drisley]

I used to use Adobe Camera Raw before I got the 20D ETC profiles for C1 Pro.
The ACR default setting does leave a little more colour noise than C1 Pro, but I still find it very clean at ISO1600. I've made huge prints of ISO1600 shots converted with ACR, and they print out super clean.
Also, there is much more detail in the ACR version. C1 Pro and many other programs are very aggressive in their noise reduction... too aggressive if you ask me. I turned off noise suppression in C1 Pro, and turned up banding suppression (which lets noise back in).
The default for C1 Pro makes images look a little plastic-y, and removes way too much detail.

HERE is a 100% crop (http://www.mts.net/~lftbrain/20d/iso1600_hockey.jpg)of an ISO1600 image converted with Photoshop CS Camera Raw. No noise reduction.

Anyway, you should NOT be getting noisy images at ISO400. Either you are viewing the images at 100% in photoshop and having too high expectations, or something else is wrong.

[Medic1]

hmmm....wierd. I'll try converting with another program and see if that makes a difference. I am surprised by that result with a program such as CS2 though....which is what I am using