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rutt
Oct-02-2005, 12:56 PM
I'm jumping the gun on Margulis Ch 5 (sorry XO), but I've been testing out Dan's ideas from that chapter. In short, I found I couldn't just apply Dan's recipe for noise reduction, but I have had some good luck with an alternative. I'm interested in getting some feedback.

I'll be working with this picture which I shot yesterday with a Canon 5D at ISO 800 at Fenway:

http://rutt.smugmug.com/photos/38251627-M.jpg
Original: here (http://rutt.smugmug.com/photos/38251627-O.jpg)

Davev suggested a great crop which really helps the picture tell its story. This is my version of his crop:

http://rutt.smugmug.com/photos/38358333-L.jpg
Original: here (http://rutt.smugmug.com/photos/38358333-L.jpg)

But now the noise is very noticeable. Davev used NoiseNinja on this image when he suggested his crop (see below). I've been reading Dan Margulis' Photoshop LAB Color, Chapter 5, so I thought it would be a good opportunity to try out a technique presented there.

Dan opens the chapter with an image with a lot of color noise. Converted to LAB, his image has little noise in the L channel and quite a bit in the A and B channels. This up and right down the middle for Dan, who shows how to blur the A and B channels, basically losing nothing but the noise.

When I tried this, I found the A and B channels pretty clean and the L channel had all the noise. Bummer. Back to the drawing board. (Actually, I've encounterd this same problem before, since Dan has been advocating blurring the A and B channels for years. And for years, Canon cameras + ACR have made images with L channel noise and clean A+B channels. I think this may be evidence that Dan still has a foot in the scanner world. I've tried to capture his attention with this issue before and now I'm trying again. He's likely to care more now that he is working a next version of Professional Photoshop with an emphasis on digital photographers.)

One thing I did learn from reading Ch 5 is that PS/CS2 has this nifty new blur tool, called "Surface blur". It works a little like unsharp mask. It can detect edge transitions and only blur where there are none (hitting them where they ain't.) Unlike USM, increasing the value of Threshold in this filter increases the amount of blurring it does. The threshold value tells it how big an edge transition to ignore. So setting the value very low means there will be no blurring where there are even subtle edge transitions. 2 is the lowest possible value.

I blurred my image's L channel with Threshold=3 and Radius=5. A Gaussian blur with a radius of 5 would destroy the fine details in this image, for example the hairs and skin texture. But surface blur did a very creditable job here:

http://rutt.smugmug.com/photos/38387906-L.jpg
Original: here. (http://rutt.smugmug.com/photos/38387906-O.jpg)

I followed with the usual LAB curves and separate lighten and darken USM and ended up with this:

http://rutt.smugmug.com/photos/38365105-L.jpg
Original: here. (http://rutt.smugmug.com/photos/38365105-O.jpg)

I think this is at least competitive with what Davev got with NoiseNinja:

http://www.pbase.com/davev/image/50139715.jpg

and has the advantage that I actually understand what it's doing.
Nikolai
Oct-02-2005, 02:07 PM
Just in the nick of time!
I was JUST about to start PS-ing some heavily noised ISO1600 pikchas from last nite. Your post would help a lot!
I have already discovered the hidden power of the surface blur for meself.
It's a great tool, but thus far I didn't used it in LAB, silly me..:dunno
I will try to follow your lead and post the results as soon as I have them:-)
Cheers!
rutt
Oct-02-2005, 02:12 PM
Just in the nick of time!
I was JUST about to start PS-ing some heavily noised ISO1600 pikchas from last nite. Your post would help a lot!
I have already discovered the hidden power of the surface blur for meself.
It's a great tool, but thus far I didn't used it in LAB, silly me..:dunno
I will try to follow your lead and post the results as soon as I have them:-)
Cheers!

Make sure to check the A and B channels first. If the noise is there, you're into Dan Margulis Ch 5 land and you won't have to be nearly as careful to get better results.
davev
Oct-02-2005, 06:24 PM
Hey rutt, that looks pretty good.

I wish I could try that lab stuff, but PSE 2 doesn't have lab in it. Or at least I
haven't seen it.

The one step that I did that you didn't was to unsharpen mask the phone screen
after I used noise ninja. With what you did, and making the screen just a hint
sharper, you've got a great photo.

P.S. you gave me way to much credit for your story telling picture.
Thanks.
Andy
Oct-02-2005, 06:31 PM
that image, imo, hardly needs any nr. apply some added curves maybe and enjoy the film-like look! just my two shekel's worth.
rutt
Oct-02-2005, 06:41 PM
that image, imo, hardly needs any nr. apply some added curves maybe and enjoy the film-like look! just my two shekel's worth.

Andy, that's a darn good point. I was just reading the chapter this and then DaveV ran this image of mine through NN so I thought I'd play. When you have a hammer, everything looks like a nail.

Still, I'd like to see what people get with images with really bad noise. I guess it can partly wait for XO's post on Ch 5, next weekend he says.
ScottMcLeod
Oct-03-2005, 06:51 AM
Andy, that's a darn good point. I was just reading the chapter this and then DaveV ran this image of mine through NN so I thought I'd play. When you have a hammer, everything looks like a nail.

Still, I'd like to see what people get with images with really bad noise. I guess it can partly wait for XO's post on Ch 5, next weekend he says.
Guess i'd better get this book eh? Looks like it's all the talk here on DG...

Does anyone know where the best supplier would be to get it for a Canadian Photog?
rutt
Oct-03-2005, 06:54 AM
Guess i'd better get this book eh? Looks like it's all the talk here on DG...

Does anyone know where the best supplier would be to get it for a Canadian Photog?

Got mine at Amazon. Barnes & Noble has been known to stock in local stores. The book is a best seller, so it's not hard to find.

And once you do get it, how about writing a chapter summary?
rutt
Oct-03-2005, 07:35 AM
Andy provided a better test of my assertion that modern Canon cameras end up with L channel noise instead of A&B noise. Here is his high ISO test of 5D and 1Ds Mark II:

http://www.moonriverphotography.com/gallery/855603/1/38499428

Here are the L, A, and B channels of the ISO 3200 crop:

http://rutt.smugmug.com/photos/38510005-O.jpghttp://rutt.smugmug.com/photos/38509968-O.jpghttp://rutt.smugmug.com/photos/38509994-O.jpg

I used surface blur on the L channel of this (where the noise is), tuning the parameters for the 5D (noiser 1Ds Mark II will require both higher threshold and radius.)

Here is Andy's original (left) and my surface blurred version (right):

http://www.moonriverphotography.com/photos/38499428-L.jpghttp://rutt.smugmug.com/photos/38511746-O.jpg

OK, let me sum up the technical part of this discussion to date.

Noncontroversial: Modern Canon cameras make much more lumonisity nose than color nose at high ISO settings.
Experimental: Surface blur of the L channel early in the work flow is a good solution for this problem.
Open: A much better solution. Noise Ninja, Neat Image, or the like are nice, but I would prefer to have a lower level more transparent solution which would actually contribute to my understanding.
rutt
Oct-03-2005, 07:54 AM
For what it's worth, here is a version of the Fenway shot with no blur, separate USM for lighten, darken layers. Darken got radius=3.2 to make the cell phone text more readable and lighten got radious=0.7 to keep the light halos on the cell phone screen from obscuring the text.

http://rutt.smugmug.com/photos/38512750-L.jpg
DavidTO
Oct-03-2005, 09:46 AM
I like the noise on the 5D.

(Weird statement).

I like the lack of noise on the 5D.

(That's better)