Dear List,
I was wondering if anybody has some experience in recovering luminance information (an HDR image) from a single RAW file.
I understand RAW files as some sort of MDR (Medium Dynamic Range) images... not as wide as a true HDR but higher than jpgs and the like...
This range could be enough to get some meaningful results in certain lighting conditions (i.e. an artificially lit interior) where contrast is limited.
I have tried a few ways to accomplish this using Photoshop or Picturenaut or LuminaceHDR but I get very different results and a million different options that end up being quite confusing.
Anyone any thoughts?
Thanks in advance,
Giovanni
Hi Giovanni,
Preserving all of the data from a camera RAW file is a tricky business. The Adobe RAW converter has a lot of options to play with and allows you to go straight into a 16-bit/channel file, which has the potential to keep everything. You still have to make choices as to how to clamp the highlights as the three channels will clip at different levels and this depends on the camera sensor, environment and white balance settings.
The ultimate control comes from the program dcraw by Dave Coffin:
http://www.cybercom.net/~dcoffin/dcraw/
I have written the attached C-shell script that uses dcraw and another excellent freeware package called exiftool to preserve 16-bit data and camera information while converting to a linear 16-bit/channel output. This will be recognized by Photosphere but may display incorrectly in other programs due to an assumed gamma.
Cheers,
-Greg
dctiff (639 Bytes)
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From: Giovanni Betti <[email protected]>
Date: October 31, 2013 5:13:48 AM PDT
Dear List,
I was wondering if anybody has some experience in recovering luminance information (an HDR image) from a single RAW file.
I understand RAW files as some sort of MDR (Medium Dynamic Range) images… not as wide as a true HDR but higher than jpgs and the like…
This range could be enough to get some meaningful results in certain lighting conditions (i.e. an artificially lit interior) where contrast is limited.
I have tried a few ways to accomplish this using Photoshop or Picturenaut or LuminaceHDR but I get very different results and a million different options that end up being quite confusing.
Anyone any thoughts?
Thanks in advance,
Giovanni
Dear List,
Apologies for cross posting but I sent this to the HDR mailing list and had no reply, I thought I'd try my luck here...
I was wondering if anybody has some experience in recovering luminance information (an HDR image) from a single RAW file.
I understand RAW files as some sort of MDR (Medium Dynamic Range) images... not as wide as a true HDR but higher than jpgs and the like...
This range could be enough to get some meaningful results in certain lighting conditions (i.e. an artificially lit interior) where contrast is limited.
I have tried a few ways to accomplish this using Photoshop or Picturenaut or LuminaceHDR but I get very different results and a million different options that end up being quite confusing.
Anyone any thoughts?
Thanks in advance,
Giovanni
I did respond. Did you not see my post (attached)?
Cheers,
-Greg
dctiff (639 Bytes)
···
Begin forwarded message:
From: "Gregory J. Ward" <[email protected]>
Date: October 31, 2013 8:23:03 AM PDT
To: High Dynamic Range Imaging <[email protected]>
Subject: Re: [HDRI] Recover HDR from RAW images
Hi Giovanni,
Preserving all of the data from a camera RAW file is a tricky business. The Adobe RAW converter has a lot of options to play with and allows you to go straight into a 16-bit/channel file, which has the potential to keep everything. You still have to make choices as to how to clamp the highlights as the three channels will clip at different levels and this depends on the camera sensor, environment and white balance settings.
The ultimate control comes from the program dcraw by Dave Coffin:
http://www.cybercom.net/~dcoffin/dcraw/
I have written the attached C-shell script that uses dcraw and another excellent freeware package called exiftool to preserve 16-bit data and camera information while converting to a linear 16-bit/channel output. This will be recognized by Photosphere but may display incorrectly in other programs due to an assumed gamma.
Cheers,
-Greg
From: Giovanni Betti <[email protected]>
Date: October 31, 2013 5:13:48 AM PDT
Dear List,
I was wondering if anybody has some experience in recovering luminance information (an HDR image) from a single RAW file.
I understand RAW files as some sort of MDR (Medium Dynamic Range) images… not as wide as a true HDR but higher than jpgs and the like…
This range could be enough to get some meaningful results in certain lighting conditions (i.e. an artificially lit interior) where contrast is limited.
I have tried a few ways to accomplish this using Photoshop or Picturenaut or LuminaceHDR but I get very different results and a million different options that end up being quite confusing.
Anyone any thoughts?
Thanks in advance,
Giovanni