Noise Test

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Old Wolf
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Noise Test

Post by Old Wolf »

Testing the amount of noise generated by sharpening.
6.jpg
test.jpg
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Old Wolf
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Re: Noise Test

Post by Old Wolf »

Sizing test
test_edited.jpg
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Old Wolf
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Re: Noise Test

Post by Old Wolf »

Testing different sharpens:
Nikon Capture NXD
Nikon Capture NXD
Photoshop
Photoshop
Please feel free to add your opinions.
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MikeOxon
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Re: Noise Test

Post by MikeOxon »

You don't state which sharpening method you use but, if it's 'Unsharp mask' then the 'Threshhold' setting is very important if you don't want to enhance noise in 'smooth' areas.

This setting determines by how much adjacent pixels have to differ, before they are recognised as an 'edge' that needs to be 'sharpened'.

FWIW, my most usual settings in Photoshop 'Unsharp Mask' are 125%, 1.7px radius, and 7 for the threshold. The radius is very dependent on the dimensions of the image - that's the figure I use for a 16 - 20 MP image.

When you reduce the size, for publishing on a website like this one, a little extra sharpening is often needed, to compensate for the reduction in detail. I find that an extra sharpening pass at about 0.5 px radius, after re-sizing, helps in restoring the apparent sharpness.

These sharpness tools don't actually 'sharpen' an image if it is out of focus, but they produce a subjective appearance by steepening the transition between lighter and darker regions. In film days, it used to be called 'acutance' and special developers could be used to enhance the effect.

Mike
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Old Wolf
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Re: Noise Test

Post by Old Wolf »

Hello Mike,
I appreciate you taking the time to help explain this :lol: your explanation is helping me understand how it works a little better.

In Capture NXD I used their version of Unsharp Mask and in Photoshop I used Smart Sharpen as I had read that it is the newer version of sharpening.

The problem I have is that Photoshop will not run on my PC so I have installed it on my daughters laptop which is much newer. I have capture NXD on the pc which has a really big screen and the laptops screen is much, much smaller.

I suppose I am really trying to see if there is all that much difference between the two programs as NXD is free and is much easier to see on the bigger screen.
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MikeOxon
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Re: Noise Test

Post by MikeOxon »

Old Wolf wrote: Tue Jun 16, 2020 6:44 pm... NXD is free and is much easier to see on the bigger screen.
A free program that is well worth investigating is GIMP, which is a Photoshop clone. see https://www.gimp.org/ There are versions for older PCs available as well as the latest version which needs at least Windows 7.

I prefer to use 'Unsharp Mask' over Photoshop Elements 'Smart Sharpen', which often seems to produce a strange frosted glass effect. The full Photoshop has more controls that can tailor it's sharpening tools more precisely. Sharpening is a bit of a black art that needs practise to do well :)

Don't forget that you can use selection tools to limit sharpening effects to particular parts of an image, without affecting the rest. Another trick is to apply a little Gaussian blur to parts of the image apart from the subject, which can have the effect of making the subject stand out more!

Mike
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Old Wolf
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Re: Noise Test

Post by Old Wolf »

Hello Mike, many thanks for your help.

It really is a rabbit hole once you start and is a bit overwhelming. It looks like I will be needing to spend quite a bit of time investigating all of the things you mention.
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