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Old September 28th, 2013, 04:14 PM
Antonio Correia Antonio Correia is offline
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Default Noise on images

I usually do not have much noise on my images but when I do, I have much trouble trying to remove it.

Perhaps my problem is that I have Nik's collection and I do not know how to use it properly. Perhaps Define 2 does an excellent job ...

I saw Brooks on LensWork using Noiseware Pro with good results but...

Do you have any suggestion on this subject please ? I feel I am making silly questions... :( instead of Googling ...
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Old September 29th, 2013, 03:15 AM
Nicolas Claris Nicolas Claris is offline
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Hi Antonio
I first do a pre denoise into Lightroom (before was with Capture One) then Define 2, if needed, does an excellent job (set to auto). Easy to lessen the percentage or even to erase some area as it is on a layer…
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Old September 29th, 2013, 05:17 AM
Bart_van_der_Wolf Bart_van_der_Wolf is offline
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Quote:
Originally Posted by Antonio Correia View Post
I usually do not have much noise on my images but when I do, I have much trouble trying to remove it.
Hi António,

Noise comes in different shapes/forms/distributions and intensities. It depends on the particular noise structure if and how we can reduce it to more acceptable proportions. We usually do not need to remove all of it, so we need to find a kind of balance. Reducing too much noise will also affect resolution, and the image may start looking like plastic, which we obviously want to avoid for most subjects. It can also make a difference what the intended output size is, and where in the workflow we apply sharpening.

There are several good software solutions for when our capture technique (!) cannot reduce the amount of noise. Good exposure levels reduce noise (increase signal to noise ratio), and when we cannot avoid underexposure (e.g. because of shutterspeed requirements), some increase of the camera's sensor gain (by selecting a higher ISO) may be warranted.

I haven't used Nik's Define, so I cannot comment on that from personal experience, but my current noise reduction favorite is Topaz Labs 'Denoise'. The noise reduction in Lightroom/ACR has improved a lot over the years, but I usually prefer the 'Denoise' results. Lightroom has a tendency to desaturate colors when a lot of noise reduction is applied.

There is a number of demo/tutorial videos available in case you want to improve your 'Define' skills (e.g. http://www.youtube.com/watch?v=z5kG10DW1_o)

Maybe you can post a true size (100% zoom) crop of a problematic image area that some of us can try to improve?

Cheers,
Bart
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Old October 1st, 2013, 12:12 PM
Antonio Correia Antonio Correia is offline
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Thank you Nicolas :)
@ Bart
Thank you Bart. Thank you very much.
I already new some of the issues you are pointing to and now, that I have been opening the image in raw in the final version, I realized that the problem may be an incorrect exposure of the photograph that being the cause of the degradation.
On the other hand, the histogram looks fine.
Most probably the noise is introduced after the manipulations I introduced to the original file until I get what I want.
This is something I really have to be careful about. As you said yourself the noise is more or less important according to the size of the final printed image, if I have understood correctly.
Normally I just do not correct noise in my photographs.
Thank you Bart ! You have been very kind ! :)

I almost forgot to say that the original is in fact 100% but the other one is a guess of the same magnification because it is cropped in one of my usual sizes.
If you decide for some reason, to edit the image I have placed it here.
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Old October 1st, 2013, 12:57 PM
Jerome Marot Jerome Marot is offline
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The noise you have in the sky of that sample is readout noise, recognisable from its structure with lines. It is typical of some Canon cameras, like the 5D. It will appear if you change the contrast or histogram considerably. Noise reduction software will not remove it, so there is not much you can do.

I am sorry, but you just found a limitation of your camera.
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Old October 1st, 2013, 01:29 PM
Wolfgang Plattner Wolfgang Plattner is offline
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Hi Antonio,

I converted your file with C1, opened the TIFF in PS6, used Topaz Clarify with preset "landscape-cloud1", did an automatic noise reduction with Neatimage and converted it into BW with Silverefex ... no remarkable noise in the picture ...
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Old October 2nd, 2013, 08:34 AM
Bart_van_der_Wolf Bart_van_der_Wolf is offline
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Quote:
Originally Posted by Antonio Correia View Post
@ Bart
Thank you Bart. Thank you very much.
I already new some of the issues you are pointing to and now, that I have been opening the image in raw in the final version, I realized that the problem may be an incorrect exposure of the photograph that being the cause of the degradation.
On the other hand, the histogram looks fine.

Hi António,

I've had a look at the Raw file data with the excellent RawDigger tool, and that shows that the exposure is excellent. The exposure is very close to clipping in the highlights, so any more exposure would have started losing highlight information.

That leaves the natural noise of light (photon shot noise), and the noise characteristics of the sensor and its read out electronics (read-noise + pattern noise). There is not much you can do about that, except use as low an ISO setting as possible (if exposure time permits). That is also important because it is a file from a camera with a 12-bit/channel ADC, and that means that even a well exposed image like this one, will have a lower S/N ratio than a more recent camera with 14-b/ch ADCs.

That leaves Raw conversion and software noise reduction as possible remedies. Since you wanted to emphasize the cloud structures in the highlights, it is important to use a Raw conversion that does not compress the highlights too much because subsequent contrast enhancement will also boost micro-contrast and noise. Lightroom and Photoshop ACR with process version 2012 will use a lot of highlight compression by default, so you would need to use a minus Highlight correction to reduce that behavior.

Personally I prefer the conversions from Phase One's CaptureOne software, with a Linear Response Curve setting, not a Film curve that also uses highlight compression. But even with that, your file does produce some challenges for an artifact free end-product.

Quote:
Most probably the noise is introduced after the manipulations I introduced to the original file until I get what I want.
Yes, I also needed to separately find a solution for this file. I had to create a mask to apply the noise reduction only to the sky, without softening the rock/ground structures. For that, Photoshop or an other Layer based editor is indispensable. DeNoise 5 also allows to target the sensor's pattern noise that is present in the clouds, which will result in a smooth sky that will then benefit a lot from applying Topaz Labs Clarity to the entire image.

Quote:
This is something I really have to be careful about. As you said yourself the noise is more or less important according to the size of the final printed image, if I have understood correctly.
Correct, at a small enough size the noise will not be easy to see, but when enlarged, it requires extra work to visually improve the output.

Cheers,
Bart
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Old October 2nd, 2013, 09:44 AM
Jerome Marot Jerome Marot is offline
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Obviously, Wolfgang and Bart found ways to process the data around the noise. What I wanted to say is not that it is impossible to avoid that noise, but that the noise structure produced by that particular series of cameras makes it very visible. With a different camera, you would also have noise in the clouds with the contrast increase that you used to get the grey values you wanted, but that noise would not have lines and would look more similar to film grain.
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Old October 2nd, 2013, 01:35 PM
Antonio Correia Antonio Correia is offline
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Excellent guys ! Excellent !
Thank you so much for the time spent writing here about this file. Thank you again :)

This image is part of a larger project which I intend to name "Distant mountains" or similar. In fact I have already worked on some 10 images and I will have to start from scratch to get a better output.

I will have a try on DeNoise. However, I wouldn't like to be very "addicted" to technical issues. I would rather concentrate on esthetical issues.
It is a fact that one comes with the other or very close :)

Thank you again. I admire your cooperation and time spent.
I said this before didn't I ? :) :)
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Old October 2nd, 2013, 01:58 PM
Antonio Correia Antonio Correia is offline
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I have to tell you that this photograph was done using and old (rather) Canon 20D with a 70-200 f/2.8 L USM IS and not with a Canon 5D as I think was mentioned above.

I deliberately wanted to photograph the mountains with long lens which made me look in a different way to the scene around me.

In fact, I was also carrying (oh my back hakes :) ) the 5D but with the 24-70 L USM f/2.8 lens for some periods.
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