I am enjoying the new Darktable 4.0 and trying to stick with the new recommended way of doing things. So, I set exposure, then use filmic and color balance RGB, in that order and the image looks good.
Trying now to use D&S to sharpen the image. Fast sharpen works, but not as well as the old sharpen module. I have played around a lot with D&S and have it sharpening very nearly as well as the old sharpen module.
Still, applying them both is better again. The old sharpen module seems to take what D&S has achieved and tweaks it a bit better again.
So, my question is, what really are the best settings for D&S for best sharpness (as opposed to fast sharpness), and can it fully replace the old sharpen module, or is it just best to use them both ?
Ive been only using the D&S for sharpening. I have a preset that applies it plus a DS for local contrast. My sharpening started from the AA preset one, but I tweaked to increase the radius span and the edge threshold.
I use two instances of D&S, one for local contrast and one for sharpen demoasicing, both from the preset. Note that youâre supposed to change the pixelpipe position when using both of these. I like the way they work. I havenât used the old sharpen module in a long time.
best settings depends on your image. Itâs about balancing the effects on edges, on grain and performance. The presets are just good start settings for some effects. Thereâs no shortcut to learn to use d&s.
But if a combination of d&s and old sharpen is fine for you - you of course can do it. Old sharpen module gives the commonly used look of unsharp mask in other tools - d&s can be used to get more subtle sharpness
So, you both use the sharpen demosaic preset? I havenât. I was just working from the fast sharpen, plus what the manual describes each control to do. I must have a closer look at this. So just what does sharpen demosaicing (with and without AA filter) mean?
I have been doing some more experimenting. It seems the best (for me anyway) place to start is to set 4th order speed to -100% (full sharpen) then play with the radius span (13 pixels on mine at the moment) and diffusion spatiality (-0.47 on mine now), then use the sharpness control as required, but 100% is my starting point. A fairly simple formula I think.
I use one of the demosaic presets together with one of the lens blur presets , but if often changes which image to image.
Candid shots on my entry level m4/3 camera often get some more (demosaic aa + lens blur medium ) , but most of my Sony a7 m2 shots for example use demosaic non-aa + lens blur soft. (I find that it does too much ).
Instead of messing with te sliders (which still are hard to grasp for me ) i only use the presets , or i take a heavy preset and use the uniform mask to change the opacity to lower the effect .
Any demosaicing step is in some way a sort of upscaling, which introduces a bit of blur . So a bit of correcting for that âis neededâ. (Nothing is really needed of course , itâs all taste ). A sensor with aa filter requires more than a sensor without aa filter . Thatâs what the two demosaic presets are for.
To sharpen up to try to get the detail back that is naturally lost by your sensor. This means it works at mostly fine details , sometimes very fine.
Think unsharp mask / rt-deconvolution with a small radius .
Even then , my cameras all have aa filters but I stil find the demosaic aa preset to over do it sometimes. So I just use the non-aa variant in those cases.
The lens blur presets appear to work on a bit if a larger radius , but still not so large that i would call it local contrast . More very fine micro contrast or something. I apply one of them to taste. Of if i know Iâve taken the shot on an old , blurry lens :).
This is all when looking at 100% in Darktable. I have a sort of rule for myself that if I look at 50%, i should not or just be able to see the sharpening effects .
Most images get downscaled for viewing somewhere after exporting , and there is some sort of output sharpening (so outside darktable).
I have been testing it with a very cheap Lumix FZ80. I am sure my Canon 80D will need less, but the FZ80 needs a good bit of sharpening. The default presets you mention have a small effect, and more is needed.
I have forced myself to start understanding the sliders. Probably a good thing long term.
Hence I am only using 3rd and 4th order speed controls - they act on the fine detail.
Not a bad idea. I do that to set things like the edge sensitivity control.
Doesnât downscaling itself result in improved sharpness when viewed at the same pixel scale? Same as standing back further away from the screen or a print.
My 2 cents worth. I use ds sharpen aa filter preset. That is my initial sharpening. For portraits that is often enough. But landsczpes and some images benefit from the sharpen module default values as well as ds. I find fast sharpen in ds underwhelming.
Try dehaze. I use that preset and usually that is enough or even too much. sometimes I add the local contrast instance. I suspect you could use a default instance and just use sharpness slider if you are happy with the old module. When I first experimented with the module it was suggested to help sharpen blurs not for sharpening but it works fine IMO at least likely as well as the old module
These are tough decisions/discussions. For example. I watched videos by @Andy_Astbury1 on capture sharpening etc in RT. During his edits he would comment how sharp it was at some point and to me it didnât look sharp enough. But likely he made the right call. Often things are over sharpened. Many JPGs end up oversharpened or with artifacts⌠My point is unless we are using some math to model it and provide a metric for âsharpnessâ. Itâs highly subjective and as you and others mention will vary from camera to camera and image to imageâŚ
Donât forget that any rescaling will change the impression of âsharpnessâ (edge contrast). Thatâs perhaps why you didnât agree with the assessment of the editor when watching the video.
And whatâs most usually called âsharpnessâ is âedge contrastâ (acuity), not separation between details. An image with a lot of fine, but low contrast, details can appear less sharp than an image with coarser details with higher contrast.
Then, the ideal amount of sharpening is also a matter of tasteâŚ
To get back to the original question: the sharpen module implements unsharp masking, which is a fast method to increase acuity. The downside of this method is that it can give halos at strong settings (high radius/high amount).
No, 'in theory â it produces blur, even if you account for the new pixel density by adjusting viewing distance. Thatâs why something like 'output sharpening â exists.
Now, a filter like lanczos or stronger bicubic settings will have a sharpening effects , including all the usual artifacts that can appear (haloing , ringing , etc âŚ).
And what i mean by it all is that you donât really have to adjust your sharpness because your FINAL output file is not sharp enough for your liking . Itâs normal to sharpen after resizing as well. So judge darktable output while still in Darktable. I thatâs good enough but the resized output isnât , sharpen the output , not in Darktable . Isnât a question that was asked , but I warn against doing this (since you seem to like what is to me an extreme amount of sharpening , but again everyone has different taste . Nothing wrong with that).
Sharpen small to âfixâ your capture device , then sharpen creatively in the edit to what you think your image needs (local contrast for example , but also extra sharpening of eyes and or eye lashes as an example ).
Then export , size down to your target output , and sharpen that so it gives the same sharpness feel as your original 100% had.
Youâll see that this differs on things like dpi , printing method , papers, inks , but also screens and pixel resolution and processing from 3rd parties, etc âŚ
I have. I consider it to be a helpful module, and has sharpening effects maybe a bit like local contrast. But local contrast, I think I have seen it called clarity?, is not the type of sharpness I mean. I am after the sharp fine detail you need for macro and also bird photography.
Yes, I know I am targetting more sharpness than many seem to want, however, I find critique of some styles of photography, like macro and bird photography, demands razor sharpness on the important in-focus part of the image (for example the birdâs eye). You often get told that an image is too soft.
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