It seems not possible to ONLY apply lens optimization from either PR4 or PL8.
Workflow 1:
Export directly from LR to PR4. In PR4 Set NR to 0, then apply standard Lens optimization, process and back to LR it applied some NR (not needed) even if it was set to 0.
Workflow 2:
Export directly from LR to PL8. Turn EVERYTHING other than Lens optimization OFF.
Re apply default preset manually first (another annoyance - PL8 messing up here, does not remember my user defined default preset…)
Check Lens optimization with default values. Then export dng (optical corrections only)
File gets back to LR with Lens optimization, but with some purpleish tint that was not there before. So I am stuck, I need to apply the lens optimization only.
#Working with Sony hi res raw files with aurora night sky images that needs special treatment.
Couple of questions/comments to get the thread moving 
1 Which Sony camera and lens, are they fully supported in PL?
2 What are Sony HiRes files? Is this a pixel shift technique to increase resolution?
3 The quality of the raw conversion in Photolab is tied to the noise reduction method chosen as DXO applies different demoasicing algorithms depending on which noised reduction method is selected.
4 DXO applies noise reduction and chromatic aberration correction (DeepPRIME during the raw conversion giving a much better result than when the chromatic aberration sliders used with other noise reduction methods. I would have thought that having the best chromatic aberration correction would be beneficial for Astro?
5 What type of file do you want Photolab to output; DNG, Tif or jpg?
ANSWERS BELOW:
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Sony A7RV/Sony GM 14/1.8 - I know it is supported in PL. Who knows if it is “fully” supported - only DxOlabs I think
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I don’t use pixel shift. But files are 61mp.
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Ok, so you are saying that if I want the DxO demosaicing (which should be better than LR. (However I never saw any other “proof” of this postulate than the YT videos editing birds wings by some other “peepers” like me
So the whole point is that I only get it by selecting some noise reduction ?
What happens then when you deselect all noise reduction in PL8 ? Will the dng then roundtrip (export) to lightroom, bypass the PL demosaicing and use the one in LR ? -
I deselected Chromatic aberration in PL8 processing. I don’t trust the PL8 CA tool. Compared with manual adjustment from LR sliders (I tested it) , LR gives (me) more true colors on the tests I have done (when adjusting it manually in LR). Besides that there is not much CA with this lens I am using. I am not trusting the PL vignette correction either, it messed up with my old canon 16-35/2.8 in PL4 and now again in PL8 with Sony GM 14 (halos)., so I turn that thing off as well. Again one of those typical DxO things that regardless of several posts writing about it here on the forum will never be responded (or fixed). So I chose to just not use it anymore and find my workarounds.
What I like to use in PL8 or PR4 is very subtle use of the XD2s algorithm - higher values gives smeary and too much strange “lofi” artefacts. I need the northern lights to still keep some of that “grainy” detail. OTOH When I want my images to “glow” I use the (higher) default value of XD/XD2s which for recent years always did a great job and saved lots of noisy Canon 6D night shots. Then the optical corrections (Lens optimization) is certainly doing something good. I can see that it gets the job done working on my files -I can clearly see the results of it in a pleasing way. I typically use the “standard” setting for lens optimization. -
I tend to use TIFF files when I want a 1:1 copy of what I do in PL but really prefer to use .dng format (if it just would work) because I sometimes roundtrip to Topaz (since I am using special (almost linear) profiles for my camera and I want that to be sitting with my (open) file as long as possible in my editing workflow .dng files are preserving the profiles/settings
Cheers
/Dan
Just a general example (lo res (54k) jpeg with lots of compression) of my work is attached.
#Compression doing lots of impact on all foreground elements. They re much cleaner on my (original hi res)
I think the easiest way forward is perhaps for you to view Andy Hutchinson’s review of DXO Photolab v8 with the new DeepPRIME 3 noise reduction. He specifically gives examples of Astro shots which should help you and hopefully facilitate this thread. 
PhotoLab is returning a linear DNG that always includes some interpretation, apart from lens corrections and demosaicing.
If you could share one of your critical, unaltered raws, we could try to see what is going on and how it could possibly be “fixed”.
Hi. Thanks for the explanation which seems logical to me.
After many years when many photographers asked for having DxO noise reduction AND Lens optimization in one plugin that could work with Lightroom, and we got it- PureRaw, which I use all the time.
Next step - if I could choose to do either the Lens optimization OR the Noise reduction solo in PureRaw would be awesome, although this is not possible and I now understand why…
This tip is actually really great and helpful. Thanks.
I did not know that there was a new algorithm besides XD2s (Deep Prime3). For some reason I did skip that because I thought it was the older Deep Prime NR. I will definitely test it out. Funny enough I mostly keep the exact same amount of force detail (-35) as Andy - just on the XD2s. Can’t wait to try the DP3.
I did not know either that the CA was a 2 step process. That may explain why I decided to never use the actual chromatic aberration tool in PL.
UPDATE: I tried it. Much better than xd2s for night skies but I still get bettter results with my astro nr plugin - so I am positive but not super impressed. Although I will still use it for some type of images (when I am lazy in need of speedier workflows )
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writing on the forum is not a bug report. If you feel a lens module is wrong (applies incorrect corrections ), please contact support.
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it is possible to open a file in Photolab, set it to ‘no corrections’, then only enable the distortion correction and export a DNG with the ‘optical corrections only’.
That file will be demosaiced, and have the distortion fixed, but nothing else. All colour values are the same, it’s still ‘raw’ and unprocessed, no highlights have been fixed, etc…
Setting NR to 0 is not the same as actually turning off the module , maybe that’s the difference you see.
nr was turned complete off in this case (pl8)
In pr4 I do not find a way to turn nr off.
So assuming we are in pl8:
I am not using the Distortion correction, only lens optimization (lens softness) which I find does a great job.
I am happy to hear that it is possible to use lens optimization only (which is exactly what is needed here)
So if that causes artefacts then there must be a bug. I will test thoroughly again and report it if needed. Thanks for your inputs.