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Author Topic: DNG Files; Preserve LCC Correction?  (Read 719 times)

JoeKitchen

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DNG Files; Preserve LCC Correction?
« on: May 18, 2018, 10:08:56 AM »

I have small weird job that I usually would not do, but since this request came from a really good client I am helping them out.  (Actually, it is for a my client's client, but I am contract through my client.) 

Essentially I need to capture four images of where a building would be going up for the renderings.  The rendering company does not want post production work done and has requested the raw files, which I am fine with. 

The only issue are the lens cast corrections.  So very few people, even retouchers, have any idea what they are, and I don't want to get into a conversation about this with my client, which would add confusion.  My plan is just to apply the LCCs on my end and export the images as DNG files. 

I've never done this before though.  Will the LCC corrections be preserved and applied in the DNG files?  I assume the rendering firm will be using LightRoom.  Will this present a problem? 

Last, do DNG files preserve all the meat in the files too?  Will highlight and shadow recovery still be as good as it normally would be? 
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Wayne Fox

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Re: DNG Files; Preserve LCC Correction?
« Reply #1 on: May 18, 2018, 11:27:22 AM »

You could convert the original raws to DNG in LR, then use  adobe's DNG Flatfield plugin in LR to generate DNG's with corrections applied.  Most DNG's I've worked with from LR seem to preserve the qualities of the original raw enough to maintain good recovery, etc.  I've tested the flat field plugin and it works pretty good.
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yaya

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Re: DNG Files; Preserve LCC Correction?
« Reply #2 on: May 18, 2018, 11:44:12 AM »

Another option is to capture the images with a linear (or linear scientific) curve, LCC them and export as 16-bit tiff. That should give the client enough "rawness" for most purposes and will ensure debayering is done in Capture One and not in another software.

BR

Yair
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BartvanderWolf

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Re: DNG Files; Preserve LCC Correction?
« Reply #3 on: May 18, 2018, 01:34:53 PM »

The rendering company does not want post production work done and has requested the raw files, which I am fine with.

Hi Joe,

Sounds like a nice project. You probably already have, but do make sure that what you call a Raw file, and what the PP company calls Raw, is the same. If my assumption is correct, they would like to create 32-bit floating point Raw conversions, to better fit in their CGI workflow. But maybe they only mean a straight Raw conversion without tonal/color/sharpening adjustments?

Quote
The only issue are the lens cast corrections.  So very few people, even retouchers, have any idea what they are, and I don't want to get into a conversation about this with my client, which would add confusion.  My plan is just to apply the LCCs on my end and export the images as DNG files. 

I've never done this before though.  Will the LCC corrections be preserved and applied in the DNG files?  I assume the rendering firm will be using LightRoom.  Will this present a problem? 

Last, do DNG files preserve all the meat in the files too?  Will highlight and shadow recovery still be as good as it normally would be?

I think that DNGs will only allow to store semi-Raw RGB converted images.

RawTherapee also offers an LCC option, called Flat Field Correction (which is the more correct generic name).
http://rawpedia.rawtherapee.com/Flat-Field
and since version 5.4 it it possible to save 32-bit floating point TIFFs
(- Added support for saving 32-bit floating-point TIFFs clamped to [0;1])

I haven't tried it (the 32-bit part, but the LCCs work fine) myself yet, but it might be what your client is actually looking for, and it offers you the opportunity to apply an LCC for significantly shifted and wide-angle lenses.

Cheers,
Bart
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JoeKitchen

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Re: DNG Files; Preserve LCC Correction?
« Reply #4 on: May 18, 2018, 02:44:15 PM »

Thanks All, I am going to have to looking into these options.
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Joe Kitchen
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"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
“Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.”  William Faulkner

Doug Peterson

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Re: DNG Files; Preserve LCC Correction?
« Reply #5 on: May 18, 2018, 03:06:43 PM »

Provide EIP packed Raw files. They'll need Capture One to open them, but they'll see *exactly* what you see in Capture One, without having to mess around with sidecars or catalogs.

ErikKaffehr

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Re: DNG Files; Preserve LCC Correction?
« Reply #6 on: May 18, 2018, 03:51:40 PM »

Hi,

DNG would normally keep the content of the raw file. But, there is something called linear DNG that would contain demosaiced data. Such files grow in size. A 16-bit DNG would in all probability maintain all tonal information.

A TIFF file is normally in a colour space that may be more limited than what the sensor can deliver, like Adobe RGB and it would probably be coded using some gamma value, so it is no a linear file. More importantly, it is quite possible/probable that a TIFF file may discard highlight and shadow detail. It is probably possible to create a 16-bit TIFF that maintains all the info in the image, but that needs some special handling.

So, I don't see a simple answer. You could try to use Capture One, do the LCC stuff and export to DNG. The latest version of Capture One I have tested screwed up white balance when exporting to DNG. Your mileage may vary.

I would strongly suggest that you test the workflow before sending off images to customers.

Best regards
Erik


You could convert the original raws to DNG in LR, then use  adobe's DNG Flatfield plugin in LR to generate DNG's with corrections applied.  Most DNG's I've worked with from LR seem to preserve the qualities of the original raw enough to maintain good recovery, etc.  I've tested the flat field plugin and it works pretty good.
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JoeKitchen

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Re: DNG Files; Preserve LCC Correction?
« Reply #7 on: May 22, 2018, 04:05:56 PM »

I did some testing and found that DNG files work fine.  Also, the use wanted the files to create reference points and textures.  Everything else would be rendered, especially considering the angles they wanted will only look good in late fail or winter from a lighting perspective.  So they are just going to render the lighting. 
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Joe Kitchen
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"Photography is one percent inspiration and ninety-nine percent moving furniture."  Arnold Newman
“Don't bother just to be better than your contemporaries or predecessors. Try to be better than yourself.”  William Faulkner

BobShaw

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Re: DNG Files; Preserve LCC Correction?
« Reply #8 on: June 22, 2018, 08:22:56 PM »

If they have asked for raw files and you have agreed to give them raw files then why not give them raw files, i.e. CR2, NEF, FFF, whatever comes out of the camera?
Seems to me they know how to process them if they have asked for them and raw files contain more information than DNG.
If they then want something else then that is chargeable.
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