New parameters for sharpening in RT5.8?

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1

Just updated from RT5.4 to RT5.8. Pretty quickly noticed a couple of new parameters associated with the “Sharpening” tool on the “Detail” tab. Couldn’t find anything in Rawpedia to explain what they mean or how to use them. Is there some kind of reference material that explains the use of the parameters “Contrast Threshold” & “Blur Radius”? It appears that they apply to both the “Unsharp Mask” and “RL Deconvolution” methods of sharpening.

I notice that “Contrast Threshold” defaults to 0 (zero). Is it possible that this prevents anything new from happening? New meaning different from RT5.4 where such values were NOT present.

2

By using a Contrast Threshold > 0, you can restrict the sharpening to areas with fine detail. To preview the mask, select >= 100% preview and press the button:

grafik
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The darker parts are sharpened less.
By using a Blur radius > 0.2 you can additionally blur the parts of the image without fine details (the darker parts in mask preview)

Also have a look at the new Capture-Sharpening in raw tab, but don’t use them together in first step. In Capture Sharpening you can use the mask preview even at < 100 % preview

3

It does not default to zero. If you press the reset button next to the adjuster, it should default to 20… At value 0, the whole image is sharpened

4

May I say that «Contrast threshold» makes reference to the amount of contrast that some part of the image has? That is, the darker areas don’t have enough contrast to be sharpened (even if they contain fine detail).

A classic example is the out of focus areas, that usually doesn’t have very high contrast in them. So with this slider you control from which amount of detail contrast the sharpening is applied or not.

On the other hand, is not unusual that areas with fine details have good contrast, too.

Am I wrong?

5

Very helpful when compared to what else I could find. Thanks for that. However, it is also good enough to trigger some questions as follows:

  1. Does that mean that Contrast Threshold = 0 would cause tool to work as in RT5.4?
  2. Fine detail implies edges does it not? If so how does this play with the option to Sharpen Edges only?
  3. Might this be just too new for making its’ way into Rawpedia by now? but we could eventually expect such. Correct?
6

I see! I must have either misread the value or inadvertently done something to change it to zero without recognizing what I’d done. Sorry about that!

7

Exactly.

No, it’s more about microcontrast in the image. Have a look at the mask preview to see what’s sharpened and what’s not sharpened.

No problem. In fact, if you open a raw which has a pp3 from an older version of RT, the value is set to zero to be backwards compatible