A further Photolab and Lightroom question

[davidedric]

I'd like some help with another PhotoLab and Lightroom question - I think this is about theory rather than products.

I have been experimenting with starting in PhotoLab to get the advantages of its RAW conversion (it does seem to give better detail on my m4/3 files) and PRIME noise reduction. Then passing the results back as a linear .dng.

I have read that once the file has been processed in PhotoLab to produce the intermediate file, Lightroom's ability to recover shadow detail, for example, is much reduced because of the nature of the RAW to .dng conversion. Therefore such edits should be made in PhotoLab before exporting to Lightroom.

I'm afraid my understanding of this is sadly limited. Can someone suggest what things I might lose going down this route.

Dave

[Shadowman]

I'm not a PhotoLab user but do use Lightroom (4.4) and have had to use DNG files for LR which doesn't support my D750 and haven't had any issues recovering shadow details from a DNG file. With the Nikon system I believe some of the Picture Controls applied in-camera might be lost but it hasn't been an issue for me.

[xpatUSA]

I'd like some help with another PhotoLab and Lightroom question - I think this is about theory rather than products.

I have been experimenting with starting in PhotoLab to get the advantages of its RAW conversion (it does seem to give better detail on my m4/3 files) and PRIME noise reduction. Then passing the results back as a linear .dng.

I have read that once the file has been processed in PhotoLab to produce the intermediate file, Lightroom's ability to recover shadow detail, for example, is much reduced because of the nature of the RAW to .dng conversion. Therefore such edits should be made in PhotoLab before exporting to Lightroom.

I'm afraid my understanding of this is sadly limited. Can someone suggest what things I might lose going down this route.

Dave

Hi Dave, "Linear DNG" got my attention. It's not quite the same as "regular" DNG and indeed not all applications will even open it.

More about that here:

http://www.barrypearson.co.uk/articles/dng/linear.htm

As a Sigma raw shooter, there is one utility that converts an X3F raw to Linear DNG. Some Sigmatistas like it, some don't. Recently, Sigma has added DNG capability to their "Quattro" series of cameras - that DNG is Linear and is 12-bit; the cameras are 14-bit. A lot of controversy in Sigmaville about that. While realizing that Sigma stuff is of little interest here, there is nonetheless a parallel with your situation.

DNG itself differs from proprietary converters in a way that Adobe is not going to tell you - the algorithms and coefficients used as tags in DNG are somebody's approximation of what the proprietary raw converter does - even if that somebody is the manufacturer hisself! That is why manufacturers have their own converters - one size does not fit all, despite whatever Adobe might imply.

As a purist, I would recommend that you convert from raw with the best possible converter, using the converter's ability to correct exposure, apply capture sharpening and not much more; then head off in TIFF to your editor of choice to do all the rest.

[dje]

I'd like some help with another PhotoLab and Lightroom question - I think this is about theory rather than products.

I have been experimenting with starting in PhotoLab to get the advantages of its RAW conversion (it does seem to give better detail on my m4/3 files) and PRIME noise reduction. Then passing the results back as a linear .dng.

I have read that once the file has been processed in PhotoLab to produce the intermediate file, Lightroom's ability to recover shadow detail, for example, is much reduced because of the nature of the RAW to .dng conversion. Therefore such edits should be made in PhotoLab before exporting to Lightroom.

I'm afraid my understanding of this is sadly limited. Can someone suggest what things I might lose going down this route.

Dave

Dave I can only surmise!

As I understand it, when DXO outputs a linear dng file, it replaces the RAW RGGB channel data with demosiaced 16 bit RGB per pixel data, with black and white levels set. If these levels are set, the shadow and highlight recovery features of LR will not be able to work as they would on a normal raw file because anything outside these levels on any of the channels will have been clipped. It would be similar I think to trying to do shadow/highlight recovery on a tiff or jpeg.

If DXO has reasonable shadow/highlight recovery functionality, you would be best to use that I think. Can you do a few tests of your own with some shots that include areas with marginally excessive exposure?

Dave

[Manfred M]

Dave - my understanding on what the DNG file that PhotoLab produces is along the lines of what Ted and Dave E have written. The PhotoLab predecessor DxO Optics Pro did not have a DNG option, so the 16-bit TIFF output was the way I would bring the files into Photoshop. All of the DxO products create a proprietary sidecar file with a .DOP extension (versus Adobe's .XMP) and so far as I know, this data cannot be ready by Adobe software.

If I output my PhotoLab work to PhotoShop and use the DNG file, it is opened in Adobe Camera Raw. I just hit the <Enter> key and send the data straight to Photoshop, where I do the bulk of my editing. It seems a bit pointless to use two different parametric editors to prepare the same file for further edits. If you check under the "Selective Tone" tab of PhotoLab, it does have a shadow slider that for the most part functions along the same lines as the ACR / Lightroom slider, albeit much more aggressively.

As I don't use Lightroom for any local edits, I can't comment on the how those tools compare with PhotoLabs. My suspicion is that Lightroom is more talented than PhotoLab, so I can see why you would want to do some work using Lightroom. As a Photoshop user, when I open a PhotoLab created DNG file, it will automatically open in Adobe Camera Raw. I don't bother with any edits there and just pass the data straight through to Photoshop, although quite frankly, my preferred path is to create a 16-bit TIFF output from PhotoLab and open that up in Photoshop.

[davidedric]

Thanks for the feedback, everyone, I (think) I now have a much better understanding of what is going on.

I think that I need to have a much better look at the DxO software to se what it can do, and run some tests. From what has been said, it seems that if I can make sure that there is no clipping in the DxO output, then I can still get the benefit of their RAW conversion, lens profiles and PRIME noise reduction. We'll see.

Dave

[Donald]

From what has been said, it seems that if I can make sure that there is no clipping in the DxO output, then I can still get the benefit of their RAW conversion, lens profiles and PRIME noise reduction.

Precisely.