You can actually set the grey point from within filmic, which has the same effect (as far as filmic is concerned) as changing the exposure. By default, the control is turned off (as it’s still recommended to get exposure right from the beginning), but you can enable it on filmic’s ‘options’ tab (‘use custom mid-grey values’):
Yes, I am well aware of that feature but exposing somebody that is new to filmic with this feature will create nothing but problems.
Again: the key to using filmic is getting the exposure correct to star with. This is my procedure as illustrated by the clip below:
What you see above is a ‘preset’ that is used for ALL of my images. On my (Fuji) camera there is a mismatch between the JPG exposure and the RAW, so I bake in that 1.43 EV difference. Further I use the camera compensation, as needed, to avoid highlight clipping or for shadow enhancement.
With this as a preset my RAW data will present a baseline 18% starting point for filmic and thus (except for rare occasions) I will not need to muck about with that value in filmic. As I said before it is blindingly easy!
filmic does provide problems with snow-scenes, high/low key and a few other oddities where the camera will simply not believe what I am trying to capture … but that is another story.
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Several weeks ago, I was studying the thread concerning ETTR. I was fired up about it, and I took my little camera out to work on it. I was blindsided by several circumstances. My Nikon D3300 is not quite up to the task, as I cannot make heads or tails about its histogram facility. Also, my eyesight is problematic, and I have to take my glasses on and off during the process of trying to set up an image and shoot it. The viewfinder is tiny. I think a better camera would help, but when I zero in on what I want, it quickly goes over $2000 for a body. Maybe my son will let me use his D750 sometime, but I’m not holding my breath.
I know that equipment does not make a good photographer, but I feel hogtied by my camera.
Yes, there is a reason why that control was hidden. Also, it isn’t just people being inexperienced. People were misusing it and then complaining that filmic didn’t work properly.
That is the way to go. dt attempts to direct the user toward good processing habits. It is generally advisable to do more of the necessary actions earlier in the pipeline because those modules are typically vetted to be safer than later ones. E.g. filmic changes the linearity.
Have you tried adjusting the diopter of the viewfinder or using the live preview?
Usually, the histogram has some sort of headroom to prevent people from clipping their highlights. Take several shots of an unfocused uniform reasonably illuminated area at various exposures and then inspect the raw files to see what this headroom is. It may change depending on your ISO and other camera settings. E.g. if the headroom is +1EV, then you know that you can expose to the clipping warning and boost your exposure +1EV beyond that limit. Always check your work though to see if you did it right.
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Yes, it’s a bit of a PITA. I had the best success with my D7000 doing spot metering on the brightest part of the scene with a +.7 to +1.0 EV. After all, the priority should be given to not blowing highlights, even if they’re not right up against the wall…
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The confusing thing about filmic is that it looks like a tone curve and users get the idea that by pushing a couple of sliders filmic can be correctly set. The reality is that this module is driven by complex algorithms that do not necessarily respond in a directly obvious manner for the user.
However, I now find that with a couple of presets and using filmic not only is my processing time down but more importantly I am achieving improved highlights and far far better shadow detail.
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Duh! Thanks, I need to check on that. I have done it with binoculars, and I think I have done it in the past with some cameras, but I haven’t even thought about it for a long time.
Very useful discussion. So, we are not supposed to fiddle around in filmic? What about the reconstruction tab?
White slider to the left = brighter highlights, to the right = dimmer highlights.
Black slider to the left =lighter shadows, to the right = darker shadows.
Set the midtones using exposure.
You don’t need much more than that
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Well … if you messed-up in creating the image initially then you might need to work with the reconstruction tab. There are lots of bells-and-whistles in the module for special circumstances. Getting the basics correct should be task number one.
Not always … there’s the rub
I think filmic is quite easy, once one understands a few key points.
It is a tone curve. Its input is the linear (twice the number → twice the physical amount of light) view of the image; its output is closer to the world of the display. The linear side is ‘HDR’ in the sense that the camera typically handles more dynamic range than the display (it needs not be a HDR composite image). Its current output is low dynamic range, but with new display technologies, that may change. The important difference is the encoding: in the output, twice the number does not mean twice the physical amount of light.
scene tab: the curve is centred around the orange dot, representing mid-grey. Even though visually it moves around when you alter the black and white relative exposures, it still represents the point around which filmic is built, and it always maps mid-grey to mid-grey (the real behaviour, keeping mid-grey at a fixed position, and re-drawing the whole graph around it, would have been rather inconvenient). The X-axis is logarithmic (values are in EV, a change of 1 unit means doubling or halving the amount of light). The white and black offsets simply describe what input values will be mapped to black and white output, respectively. Even if one of the previous modules seemingly pushed highlights to clipping, those can be recovered, given that the raw sensor input was not clipped. Negative shadow values cannot be recovered; in exposure, one may use the black level to make sure no value is pushed below zero.
look tab: contrast defines the steepness (contrast) around mid-grey. Latitude defines the range in which this contrast is maintained. The same latitude is used for retention of colour saturation: outside the range, contrast and saturation both drop: shadows and highlights will be desaturated so black and white will be neutral; contrast will drop as shown by the shoulder and toe of the curve. Shadow/highlight balance allows you to slide the range higher or lower. If the graph misbehaves (becomes non-monotonic, which means contrast is inverted; such parts are shown in orange), you can:
- reduce contrast
- reduce latitude
- slide the range.
The first two always work (if you reduce them enough), the third one may or may not work, depending on how much the curve is messed up.
This should be enough to get started.
Create a black-to-white ramp in the Gimp (save as a PNG or JPG), load it into darktable, move exposure, turn on filmic, place a few colour samplers on the image, and adjust settings. This will help understand filmic. See Darktable - Workflow approaches - Custom Base curves, LUTS, Filmic - #20 by kofa
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When? Please explain.
without a doubt filmic works, for me with my imagery, most of the time and the sliders are totally predictable but there are occasions when either one or both of the sliders appear to give totally negative responses.
This why I say that we must not look upon filmic as a simple drop-in for a tone curve our sliders are doing far more than ‘add-shadow’, ‘add-highlights’.
Now you are going to ask for a specific example … and I will try to dig one out later so as to satisfy your question.
More importantly is the why. … I think it all falls back on the type of image and how I have initially set the exposure. I think that there are times when the ‘clever’ algorithm simply scratches its head and wonders just how to deal with such an oddity.
If you have not come across this situation it may be that your material is more uniform than mine. I have been running filmic over images taken over the past 10 years with a variety of cameras and often in unusual situations in an effort to find just how this latest dt direction changes the look of my material.
I am by the way running the daily git version on Manjaro/Arch.
I’m interested in your results… Unless you’re getting negative RGB values, which completely mucks up things, then filmic should behave predictably.
As with any algorithm big or small, filmic comes with a set of assumptions about an (input) image. If they aren’t fulfilled, then obviously it won’t be able to handle it. There are going to be images that won’t like flimic or require preparation. I have come across many Play Raws like that.
There is another factor that we are missing in our discussion. Even if the basic filmic works as advertised, there is still the aesthetic component. The user might not like the outcome. To be sure, dt’s module provides controls that could assist with that; but sometimes, it becomes all about that so much so that people make a mountain out of a molehill. I think that is why there is so much discussion about it.
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@kofa If I am getting the discussion off course, ignore this. You brought up black level correction in exposure. Since it affects filmic, may I ask: the manual says, “Adjust the black level point to unclip negative RGB values.” Do I look at the histogram and change black level to move the left side of the histogram graph off the left edge of the histogram box? Is that what that means?
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