# When not to remove chromatic aberration ??



## ralf11 (Apr 27, 2018)

I s there any condition under which I would NOT want to use the Lens profiles to remove CA?

i.e. does removal involve any distortions or noise, etc.?

I have about 5,000 photos in the catalog so far, from a variety of cameras Nikon D610 using the 24-85, an old screwdrive 300mm, various DX lenses on DX bodies, cheap old Canon or Optios, Lumix GX85 with the Leica 12-60, macro & Nikon micro lenses, etc.

If there are any lenses to not use remove CA on, let me know.


----------



## Johan Elzenga (Apr 27, 2018)

I don't see any reason to not remove it.


----------



## Hoggy (Apr 29, 2018)

I _have_ noticed occasions where the automatic 'tick-box' CA removal will cause a colorless outline around edges.  Some photos might even have that outline a bit when it's unticked, and ticking it will make it worse.  In some situations, you may just need to untick it and do manual fringe corrections.  In yet others, you may not be able to remove the outline, and the best you can do is mitigate it by doing a 'balancing act' --- as in some CA/fringe will generally be indistinguishable to outsiders, so it may look more natural to leave a little in, in those difficult situations.

Hopefully I'm making sense there. 

It's not often that the automatic CA removal will make things worse, but I have seen it happen in my experience.


----------



## LRList001 (Apr 30, 2018)

ralf11 said:


> I s there any condition under which I would NOT want to use the Lens profiles to remove CA?
> 
> i.e. does removal involve any distortions or noise, etc.?
> [snip]
> ...



Mirror lenses should have virtually zero CA.  If they were just the mirrors it would be zero, but there is some glass.


----------



## Victoria Bampton (Apr 30, 2018)

It was not enabled by default because it can slow performance slightly, and can introduce new fringing on occasion. That's pretty rare though, so I'd have it turned on by default for wide angle DSLR lenses that often show CA.


----------



## ralf11 (Apr 30, 2018)

Thanks all.  I have 2 more questions:

1. How can I turn both checkmarks on for all the 5,000+ files in my Catalog?

2. How can I have LR run thru and show me just the ones where it could not find a correction profile and generated that little error msg on the RH panel?


----------



## Johan Elzenga (Apr 30, 2018)

1: Select all 5000 images, go to Develop / Lens corrections and check the Chromatic Aberration box, press the Sync... button and in the dialog that comes up only check the 'Chromatic aberrations' checkbox.
2: I don't think you can search on that.


----------



## Hoggy (May 1, 2018)

Victoria Bampton said:


> That's pretty rare though, so I'd have it turned on by default for wide angle DSLR lenses that often show CA.



That wide-angle CA thing is one the 'rules' I seem to keep forgetting, no matter how many times I re-hear it.  
So what I do is just have it enabled all the time, via either import preset and/or camera-default.  Then if I notice it causing possible problems, I'll then do my 'investigation' routine.


----------



## LRList001 (May 1, 2018)

ralf11 said:


> Thanks all.  I have 2 more questions:
> 
> [snip]
> 2. How can I have LR run thru and show me just the ones where it could not find a correction profile and generated that little error msg on the RH panel?



You could use the metadata to set a filtre on the body and lens combination.  That would find all the ones for that combination, once you have found one that doesn't.  Not perfect but better than nothing.
BTW, the top end, expensive long lenses have very low CAs too.  All that money does go somewhere!


----------



## ralf11 (May 1, 2018)

Thx - Can I trust that it is only certain lenses, lens+body combo, or all-in-one cameras that have lens corrections lacking?

I seem to be finding out that LR is a very poor database program...


----------



## LRList001 (May 1, 2018)

ralf11 said:


> Thx - Can I trust that it is only certain lenses, lens+body combo, or all-in-one cameras that have lens corrections lacking?
> 
> I seem to be finding out that LR is a very poor database program...



No.  I can only speak to LR 6 (and before).  For some reason LR will fail to apply the corrections to lenses it does know about, from time to time.  It is a 'feature'.  I don't know if it is fixed in LR7/Classic/whatever.  It is easy to know when LR has [not] done this as by selecting the lens manufacturer (make), LR fills in the rest automatically.  You might be thinking about LR the wrong way.  Like all software, LR has idiosyncrasies.  Some are bugs, some are features and some are down to user error.  As you are just starting out, most problems will be user error.  Learn to do things the LR way and it will improve.  LR is by far, by a country mile, better all round than alternative products.  There are others that out perform LR in some key areas, (eg parts of Develop), but none match the totality of the package as a workflow.  LR is a raw editor and is poor at local corrections.  It is not a layers editor at all.  LR is it its best making global adjustments.  It is also excellent at handling a shoot with thousands of images (this is where the competitors fall down, or even fall over).  Given LR is built on MS's SQL engine, I'm not sure what you mean by LR being a poor database program.  It isn't a database program at all, it is a raw editor.  I suggest you get a book on LR to learn the basics.  HTHs.


----------



## Hoggy (May 1, 2018)

ralf11 said:


> I seem to be finding out that LR is a very poor database program...


 
  Yeah, LR is a damn good DAM and editor *with* a database, but a database program, it is not.  There are some quite basic improvements in DAM functionality that have been suggested by even some high-profile people in the industry since the betas, but still haven't materialized.

But like LRList says, it beats other similar programs by a country mile.  Capture One may be inching closer toward the DAM functionality, but only inching..  And after several years, it still chokes on a measly ~3000 image catalog, when I test drive it at many dot releases!


----------



## ralf11 (May 1, 2018)

I've read 3 or 4 books on LR.  I come from a world where you can search on a lot of 'things' in a database, and I will point out that:
1. LR is claimed to do 'Library Management'
2. Implementation of a program on top of SQL does not address how well or thoroughly the implementation is done.

I can readily accept the LR is better than others of its kind however.


----------



## PhilBurton (May 2, 2018)

LRList001 said:


> Given LR is built on MS's SQL engine, I'm not sure what you mean by LR being a poor database program.  It isn't a database program at all, it is a raw editor.  I suggest you get a book on LR to learn the basics.  HTHs.



Lightroom does NOT utilize MS's SQL Server as its database engine.  I wish it were.   First,  people who are knowledgeable in this area will all tell you that it uses a free _client _database called sqlite.  Sqlite has several deficiencies.  It can't support multi-user operation, and it can't support a catalog based on a different system and access via LAN.

Regardless, the issue is how well the program solves user problems and addresses user needs.  And there are many discussions here on this forum addressing these points.

Phil


----------

