Help request for noise issue (I think) I'm having...

[Wes Duenkel]

Ok, I've been struggling with this for a while, and I can't seem to find the cause. It seems that with the cameras I've used (Canon 20D, 5D, and 1DMKII), all the images appear "noisy" in the dark areas. Noise is there at all ISOs. Black tires are an excellent example. As the tire meets the road, the gradient will be fairly smooth until a certain point, and then "all hell breaks loose." Very noisy. Here is an example:

http://www.wesduenkel.com/Download/20071005_0655_noise.jpg

I can see it on my laptop LCD, but for those of you looking at CRTs, save it and use the eyedropper tool in the dark areas. The RGB values jump all over the place from pixel to pixel.

This was from my 1DMKII at ISO400, converted in Adobe Camera Raw/PS CS3. Default noise reduction settings, no sharpening. Fiddling with the nose reduction settings seems to "blur" the noise, but still not totally effective.

I've looked at other images, and those shot with Nikons don't seem to have this problem (this may be a coincidence). Is this a characteristic of Canons, or is the solution in my workflow/software?

I'll wait patiently (especially from you Nikon shooters).

Thanks in advance for the insight. If you need more info, please holler!

[John Waugh]

Check a conversion in Canon DPP or Aperture. ACR is not noted as the cleanest of raw converters.

[John Jovic]

I've only experience with the 20 D, not 5D or 1dmk2, but I know the 20D is quite noisy. I only ever use it at 400 out of desperation.

There['s an intersting thread on Canon DPP and ACR here. (http://www.fredmiranda.com/forum/topic/581543)
I thought the 5d had very little noise, is this an issue?

JJ

[Wes Duenkel]

Thanks for the tips John(s)! I converted one in DPP, and the noise level improved somewhat, but not as much as I would've hoped.

JJ, thanks for the link to the discussion. Enough info to make my head spin!

Unfortunately, I really like the workflow offered by Bridge/ACR/C3, and find DPP pretty "clunky" for processing lots of images...but if it helps with tackling this noise, I'm willing to give it a try...

I'm new to noise reduction techniques. I did a search for "noise," and kinda "got the phone book." Are there any good links to where I can learn more about noise reduction?

[Daniel Buck]

I've found that if you are shooting something where there is a dark area (like the tire, great example) and you convert your files with zero contrast (flat curve), there will always be a bit of noise in the shadows. Since I shoot alot of sunset stuff, that leaves alot of dark areas that have a bit of noise, even at 100ISO with short exposures (less than 1 second). Yours is more than what I usually see, probably because you are shooting 400 iso.

The way I've combated this was either with multiple exposures (of the same exposure, then layer them together in photoshop, like astro-photography to get rid of noise), or either crunch the shadows down with contrast till you don't see the noise, or use noise ninja or some other noise reduction software then blend that clean plate into your shadows with a mask (so the rest of your image isn't affected).

I've seen this on every digital camera I've used, Canon or Nikon. The way this is usually not noticed is because the in-camera .jpg files have some contrast applied, or when someone converts a raw file there is come contrast applied. I like do do all my contrast in photoshop, so I always convert my files as flat as possible. Maybe this is what you are seeing?

I'm hoping Digic 3 takes care of this problem, if it does I may have to swap my 1Ds2 for whatever replaces the 5d, assuming it has the digic 3.

On a side note, it looks like there is already some noise reduction going on, the shadows appear to have mostly luma noise, not much chroma. And there is a bit of chroma bluring going on around the text on the bumper.

[Wes Duenkel]

Thanks for the great response.
I've found that if you are shooting something where there is a dark area (like the tire, great example) and you convert your files with zero contrast (flat curve), there will always be a bit of noise in the shadows. Since I shoot alot of sunset stuff, that leaves alot of dark areas that have a bit of noise, even at 100ISO with short exposures (less than 1 second). Yours is more than what I usually see, probably because you are shooting 400 iso.

The way I've combated this was either with multiple exposures (of the same exposure, then layer them together in photoshop, like astro-photography to get rid of noise), or either crunch the shadows down with contrast till you don't see the noise,
When you mean "crunch," do you mean make them "blacker" and "clip" them more?
or use noise ninja or some other noise reduction software then blend that clean plate into your shadows with a mask (so the rest of your image isn't affected).
I also tried doing a "smart blur" at radius=1, threshold=10, and that helped quite a bit in "smoothening" the image. Is that a ligitimate route as well?

I've seen this on every digital camera I've used, Canon or Nikon. The way this is usually not noticed is because the in-camera .jpg files have some contrast applied, or when someone converts a raw file there is come contrast applied. I like do do all my contrast in photoshop, so I always convert my files as flat as possible. Maybe this is what you are seeing?
Seems to be that way, I do prefer to process as "flat" as possible as well, so I guess you're right.

I'm hoping Digic 3 takes care of this problem, if it does I may have to swap my 1Ds2 for whatever replaces the 5d, assuming it has the digic 3.
Agreed. A "5D replacement" and a 1DMKIII are on my "wish list" for next year. "?D" for still work, and MKIII for track duty.

On a side note, it looks like there is already some noise reduction going on, the shadows appear to have mostly luma noise, not much chroma. And there is a bit of chroma bluring going on around the text on the bumper.
Yes, the default ACR settings are 0=luma noise reduction, 25=chroma noise reduction. Dang, you can pick that stuff out!

*sigh* The "off season" gives me time to torture myself by obsessing about such things...instead of taking pictures :rolleyes:

[Daniel Buck]

by "crunching" I mean condensing darker values more towards 0, not actually clipping 0, but condensing the dark values, like an "S" curve, pushing the darker values down. Just normal contast usually hides the noise that a 'flat' conversion shows.

Not sure if the smart blur would do anything, but blurring would certainly reduce noise, as long as it doesn't start bluring your details :-) When you do your bluring layer, you can select your highlights, invert that and use it as your mask for your blurred/clean layer. CTRL ALT SHIFT ~ (tilde) is a quick simple way to select your highlights, then just invert the selection and use it as your mask. That would keep your noise reduction techniques off your highlights and most of your midtones :-) You might be able to do a bit more aggressive noise reduction with this technique, as you won't be messing with the rest of your image.

I wouldn't torture yourself over it. A bit of noise probably doesn't hurt. For stills that you sit there for 20 minutes doing one shot, I'd obsess over it a bit more (like taking multiple shots and stacking them astro-photo like) but for track shots, I imagine a bit of noise wouldn't detract from the shot much. Is the noise very visible at the print/display resolution?

[Wes Duenkel]

by "crunching" I mean condensing darker values more towards 0, not actually clipping 0, but condensing the dark values, like an "S" curve, pushing the darker values down. Just normal contast usually hides the noise that a 'flat' conversion shows.[;quote]
Understood.

[QUOTE]Not sure if the smart blur would do anything, but blurring would certainly reduce noise, as long as it doesn't start bluring your details :-) When you do your bluring layer, you can select your highlights, invert that and use it as your mask for your blurred/clean layer. CTRL ALT SHIFT ~ (tilde) is a quick simple way to select your highlights, then just invert the selection and use it as your mask. That would keep your noise reduction techniques off your highlights and most of your midtones :-) You might be able to do a bit more aggressive noise reduction with this technique, as you won't be messing with the rest of your image.
Great idea! I've never really played with those type of selections...I just use the brush, which can be a pain sometimes. :p

I wouldn't torture yourself over it.
Too late ;)
A bit of noise probably doesn't hurt. For stills that you sit there for 20 minutes doing one shot, I'd obsess over it a bit more (like taking multiple shots and stacking them astro-photo like) but for track shots, I imagine a bit of noise wouldn't detract from the shot much. Is the noise very visible at the print/display resolution?
It doesn't display too badly, but I'm just trying achieve that "extra something" the images of my "heros" possess. This is (to me) a very low-noise image (especially in the blacks):
http://www.gtphotographic.demon.co.uk/album/slides/ALMS_07_Laguna_1112_Lister_filtered.html
Makes me wonder "how does he do that?" late at night...

Thanks for the tips...keep 'em coming ;)

[Daniel Buck]

some of the other pictures on that link you gave show some noise reduction. Probably done in Noise Ninja, or some other noise program/plugin. The dark night shots have a slight "plasticy" look that is common on noise processed images. My guess is that he is using noise reduction on those brighter images just the same, but using it just enough so that you don't notice the effects of the processing.

for $75 (or whatever) noise ninja might be worth a shot. We have a copy of it at work, and it seems to work quite well. We us it on some of our scanned film plates, it works much better than most other high-end compositing software's noise reduction.

[Wes Duenkel]

Just installed the Noise Ninja plugin. This may be the ticket...thanks for the lead!

[Daniel Buck]

when you get it running, an 'auto profile from image' should get you most of the way there. There may be presets for different cameras and ISO levels, but an auto profile, or even a user selected profile (you can draw a box around a flat area that has noise) will probably do better on a per-image basis. Then you can dial in your luma and chroma. I usually slide down the sharpening, since I do that at my final print/display resolution only. Noise correct at full res, then down res and sharpen :-)

You can also paint in and out noise reduction right there in NN, but I prefer to do it in the layer mask. Just personal preference.