RAW processors

here's an example



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Interesting example. After seeing that, I tried a similar image of tree branches against a blown (?) sky. RawDigger showed the RAW to be blown in green and blue channels.

Although the difference was not quite so clear as in your example, ACR6.2 did rather better than RawTherapee V4.0 in recovering the sky and detail of the branches.

Andrew

Gee, the forum must be absolutely littered with all this nonsense! But you may have missed the last sentence - 'LR is no different in that respect really is it, at least as far as pure RAW conversion goes?'.

Thats the distinction isn't it? 'Pure RAW conversion' is nothing to do with JPEGs or TIFFs - I'm aware that LR performs non-destructive edits on these as well, so I have clearly qualified my comparison with other software by those words quoted above. How is this an example of my lack of authority or vague understanding of LR?

But, what is the big deal about who exactly it is that says things? It shouldn't be about the person, it should be about the argument - that's the mantra we're encouraged to follow So if you can actually find something I have said about LR to pull apart then lets see it. No doubt the details will be helpful in this context to everyone who's considering what they might choose to try out.

What the others here are looking at in highlight recovery is more interesting I think -


Andrew, were you the using just the main Highlight Recovery slider at the top of the 'Exposure' panel, or also the 'High Quality' controls further down. I don't know why, but I find that after activating these the highlights can jump way back up again, so you have to pull them back with the sliders further down under 'High Quality'.

Also as I said above, for coloured textures the 'Colour Propogation' mode works a treat, but I have no idea what the other options do? Would they provide a better solution to the blown clouds in that example shot maybe?

The RAW is here, anyone can play

Yes.

I only spent a couple of minutes each with ACR6.2 (Elements 8 ) and Ratherapee V4.0 (already past my bedtime). I'll have another look tomorrow and see if I can do any better. Once I'm convinced there is no more to be had, I'll post some crops.

Andrew

I did have another quick whizz with a different (clipped) image of trees against the sky, using ACR 6.2 and alternatively, Rawtherapee (RT), tried the "High Quality" controls in RT - and got the reverse result - the RT image was much better.

I don't really think I can draw any conclusion so far - experimental error might well have a greater effect than the difference between the two raw converters. I'll try again in a more measured way, once I've fixed the central heating

Andrew

Thats interesting Andrew. I'll have a go with kh's file later as well. I was having trouble with some shots a few weeks ago taken from under a tree canopy (the Coombe Wood images) - could't get the blown sky right. I was lazy at RAW stage I think, and ended up using a magic wand selection then levels in PS Elements to pull the highs down and add blue, but it wasn't successful.

The limitation with a converter, such as in RT, is there's no way to select tiny specks of similar tone through a darker one (like trees), so you get some bleed off of the recovery into the darker areas as well, and colour shifts as you guys were talking about above.

But there's that slider just under the 'Amount' for controlling the extent of the effect in terms of brightness value - maybe that could do it? Its kind of like a selection too.

OK, I've been working on kh's file, the winter super-wide angle scene with blown clouds through the trees. A very tricky image I think.

I've carried out comparison processing in PDCU and RawTherapee.

Firstly here's the image converted in PDCU with default settings :






As can be seen the blown clouds are quite severe, and it really screws up the colours around the trees, with loads of PF all over the place.

Next, I carried out basic general adjustments and detailed highlight recovery in PDCU - the strength of the sliders ended up being mostly at maximum to get it back to what seemed a reasonably balanced exposure. In the end the white value (RGB) is 237.







But you can see despite the balanced exposure there are still plenty of issues around the tree details, with colour bleeding that I could not get under control.

Next was RawTherapee - this took a bit longer, and I used general adjustments to try and match the overall look of the PDCU version, but I activated 'High Quality' highlight recovery section, plus the 'Highlight Reconstruction' drop down. ere I experimented with the different settings, settling on 'Luminance' as the method.






In my view this has produced a far better result - there is a smoother contrast overall, and a much better blend with the recovered cloud highlights and the dark tree branches - there's far less PF and colour bleeding - a great result I think. The white value on this shot is 231.

This is why I am using RaswTherape now for this kind of more tricky image - it just seems to have this greater capability.

Here are crops of the sky areas -

1) PDCU :






2) RawTherapee :








All we need now is a Lightroom authority to see how it can cope

Fascinating !

The shot was taken with the Samyang 8mm fisheye so I'd expect some PF, CA and fuzziness. Much of the white sky is blown - not a great deal can be done about that. The problem is the colour bleeding from the blue parts of the sky into the thin dark tree branches, making them oddly dark blue. It could be fixed later in say PS by selective desaturation, but that is not the point. The RAW processors should be able to control this in the first place.

BTW, this was just the first shot I'd grabbed from my disk when looking for an example - I am in no way attached to it and I don't think that it has any special artistic merit

I'm not surprised Raw Therapee does well here - it has always been top notch for demosaic and highlight reconstruction. To my surprise I also rather like the rendering of PDCU on default settings as well. Here is my go with darktable ...




Not deliberately cropped but a result of the distortion correction which I didn't disable.

A quick play around with Lightroom! Its very difficult to get rid of blue tinging in these situations.

LIghtroom 4 does it excellently with the Defringe controls. the only problem is that you can remove bits of blue sky as well. To help avoid this the adjustment brush has a defringe parameter to allow you to either mask in or mask out defringe application

Here's the top left corner Lightroom 4 @ 200% ....

1] Original Both CA and fringing visible

2] CA removal applied, which leaves the Blue fringing

3] then Defringing is applied tuned to the blue...

Rawtherapee seems to do OK too. This was processed using auto CA correction. The blue fringing was removed in Photoshop Elements 8 using the Hue/Saturation tool.




This version was processed in PSE8, using ACR6.2 and PTLens to remove the CA.




The difference between this and the Rawtherapee version is probably down to the demosaicing algorithm and highlight reconstruction.

Andrew

CA and fringing are not the problem. It is the colour bleed from the near clipped blue sky areas into the fine dark branches.