A little processing gotcha: LR with A7RII

[tashley]

Now this file is extreme: it was terribly low light and I underexposed it two stops (quick way of overriding the max ISO limitation I had set) but I have seen this in some other files too. This is the original:

This is how I chose to process it: (not very successfully!)

The processing involved pushing by 2.2 stops, sharpening of 60/0.7/70/20 and luminance NR of 25, then some heavy extra local NR in the sky.

I noticed some vey weird effects - and crucially I noticed three things:

1) that they disappeared when I turned lens corrections off
2) that they do export to JPEG, so it isn't a LR screen rendering issue
3) the NR makes them better and the sharpening makes them worse, as you'd expect.

SO here are sky crops from a copy of the file WITHOUT any local area adjustments. The first with Lens Corrections ON and the second with them OFF:

And here's what it can also look like, from another similar file with sharpening as above and no NR, underexposed 2 stops but not pushed in post.

No biggie, these files are poorly exposed and quite strongly sharpened but I found it interesting so I thought I'd share. Might be worth turning off lens corrections under any such extreme circumstances...

 

[Vivek]

Tim, Please keep them coming as you work through your captures with your new r2.

 

[Malina DZ]

...I noticed some vey weird effects - and crucially I noticed three things:
1) that they disappeared when I turned lens corrections off...

Thank you for sharing your observations Tim. Does that first point of yours refer to "lens corrections" in post processing or in-camera?

...underexposed 2 stops but not pushed in post.

Not good, pretty visible uniform radial noise pattern that didn't go away with "lens corrections" OFF. Might be a result of iso6400 and Sony's baked-in file compression?
How do files look like at iso800 and below for a similar scene? It'd be interesting to inspect the sky on landscape shots at sunset at various ISOs.

 

[tashley]

Thank you for sharing your observations Tim. Does that first point of yours refer to "lens corrections" in post processing or in-camera?


Not good, pretty visible uniform radial noise pattern that didn't go away with "lens corrections" OFF. Might be a result of iso6400 and Sony's baked-in file compression?
How do files look like at iso800 and below for a similar scene? It'd be interesting to inspect the sky on landscape shots at sunset at various ISOs.

I mean with the corrections off in post. In camera I leave them set mostly to Auto, because I have yet to bottom out which corrections are applied to RAW files and which aren't. In the A7R with whatever version of LR we were on in late 2013, this would mean that shading corrections were applied but that CA and Distortion corrections were not (i.e. only applied to JPEG) but that seems to have changed (in other words shading corrections are not made to the RAW file but are left to post) and when I have a chance I'll look into it. I doubt it's a factor here but it could be.

When I get a chance I'll also shoot a series but for now I can show you this: shot at ISO 1250 and -1EV comp, then with shadows boosted 36 in post, sharpening at 60/0.7/70/20 and no NR. Lens corrections OFF in post, Auto in camera.

Whole file:

Crop as above:

Now with two changes made but otherwise as above: sharpening to 100 and Lens Corrections On:

In that last crop there's a sort of tartan grid pattern (it's actually a lot more obvious when you look at a big portion of the file but you can see it here.)

Again no biggie: I never sharpen to +100 and to expect an ISO 1250 file, underexposed by 1 stop and then with a significant shadow boost to hold up to that level of sharpening is beyond what I would consider reasonable. But it does seem to imply that there's some pattern noise lurking and that it is exacerbated by post production LR lens corrections. I'll take a look at the same file in C1 when I get a chance. Important too to note that the tartan grid ONLY appears when you turn LC on. The sharpening alone is not enough to reveal it.

It's maybe of slightly more than academic interest though because the reason I dumped Canon was that the files often made me feel uneasy without being able to say why, then you'd torture push them I'm post and the reason became evident: pattern noise that you couldn't quite put your finger on when normally processed but was lurking enough to be subliminally annoying.

 

[vjbelle]

I know you're concentrating on LR but have you also tried a different processing engine.... C1 or Iridient? I suspect that they will be similar but it would be interesting to see if there is any 'real' difference.

Victor

 

[tashley]

I know you're concentrating on LR but have you also tried a different processing engine.... C1 or Iridient? I suspect that they will be similar but it would be interesting to see if there is any 'real' difference.

Victor

I just tried C1 and I can make the pattern emerge there. It is more subtle and takes more sharpening but it's there and in exactly the same way it disappears if I turn off lens corrections.

 

[spence]

Thank you Tim. More discussion of the same phenomenon here.

There's an example shot halfway down the first page which shows it very clearly. The conclusion seemed to be that the in-camera corrections were responsible for much of the issue, but it's not clear to me how bad things still looked with in-camera corrections turned off. More testing is definitely warranted.

 

[tashley]

Thanks for that. Maybe that's why when the MkII is set to Distortion corrections Auto it doesn't apply them to a raw file, whereas the MKI from memory did. It's only really noticeable to me when using distortion corrections in post.

Thank you Tim. More discussion of the same phenomenon here.

There's an example shot halfway down the first page which shows it very clearly. The conclusion seemed to be that the in-camera corrections were responsible for much of the issue, but it's not clear to me how bad things still looked with in-camera corrections turned off. More testing is definitely warranted.

 

[pegelli]

Tim, I just played a little in LR with Quentin's shot of the building construction site (his DSC00009) which I downloaded via a link in one of his posts on Luminous Landscape a few days ago.

I can make the concentric rings appear there as well but it has mainly to do with the lens correction profiles (as you already remarked). When disabled they don't show and using profiles for other lenses (for instance the 24-240 profile) all make different patterns.

So it's probably got more to do with how lens corrections are applied in Lightroom then with the camera.

I don't have C1, so can't play with that at the moment.

Here's the 1:1 crops (Quentin, this is one of your pictures, if you want me to take them out let me know, I'll happily comply with that)

Lightroom: 150 sharpening, 0.5, detail 100 and clarity 100 on all. No additional sharpening applied during export.

No lens profile:


With the FE16-35 profile applied (right profile for the lens):


With the FE24-240 profile applied (wrong profile for the lens):


All-in-all these are ridiculously extreme sharpening and clarity settings so not a real life problem I think.

 

[Viramati]

I am not really an expert in these areas but I remember in Lr5 when they first introduced correction profiles for Voigtlander lenses you used to get terrible circle artefacts like the ones shown in the dpreview thread with the correction for the CV21/1.8. This was later rectified in an update so I wonder if this in fact an adobe problem and maybe they should be notified

 

[spence]

I dunno Pegelli, I'm still seeing some pretty bad vertical pattern noise in the "no profile" shot. Is it just me?

I think the DPR thread concluded that the in-camera corrections need to be turned off, prior to even taking the shot, to achieve the best outcome.

Hopefully someone will be able to test that further.

 

[pegelli]

I dunno Pegelli, I'm still seeing some pretty bad vertical pattern noise in the "no profile" shot. Is it just me?

I see a very faint pattern indeed, but with any normal LR settings it's gone. Even 100 clarity with normal sharpening settings is very smooth.