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RESIZE option in LR4's Convert to DNG and DNG Converter 7

Feb 10, 2012 4:19 AM

Tags: #dng #resize #lossy #dng_conversion #convert_photos_to_dng

Besides the option for lossy compression I would love to see the Resize option from LR4 Beta's Export dialog in DNG Converter 7 as well as in LR4's "Library>Convert to DNG" function.

In the wake of cameras like the Nikon D800 and others with huge image files and easy option to convert to smaller sized DNGs would be very helpful.

 
Replies
  • Currently Being Moderated
    Feb 10, 2012 4:27 AM   in reply to Thomas Geist

    This is a pretty great idea. It could have two options, half size and quarter size, and produce a kind of sRAW file, turning 36 good megapixels into 18 and 9 super-megapixels, etc. You could then archive the originals elsewhere and just use the half and quarter-size dngs to work with.

     
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  • Currently Being Moderated
    Feb 10, 2012 4:37 AM   in reply to Thomas Geist

    We're not talking about export formats such as JPEG and TIFF, but specificially about an option to create smaller dng raw files — that is, with fewer total megapixels, but stil raw — which isn't now possible.

     
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  • Andrew Rodney
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    Apr 16, 2009
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    Feb 10, 2012 6:30 AM   in reply to Mark Alan Thomas

    Mark Alan Thomas wrote:

     

    We're not talking about export formats such as JPEG and TIFF, but specificially about an option to create smaller dng raw files — that is, with fewer total megapixels, but stil raw — which isn't now possible.

     

    Keep in mind that the newer Lossy DNG isn’t strictly a raw file any longer. It is  scene rereferred and partially processed data.

     
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  • Currently Being Moderated
    Feb 10, 2012 6:37 AM   in reply to Thomas Geist

    Thomas Geist wrote:

     

    All i'm asking for is more convenience with it.

     

    It's too dangerous to be that convenient.

     
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  • Currently Being Moderated
    Feb 10, 2012 6:54 AM   in reply to Thomas Geist

    Thomas Geist wrote:

     

    You think so? I'd assume that users employing the "Convert to DNG" dialog or using DNG converter are more of the savvy kind.

     

    Convert to DNG is essentially a way to destroy your originals.  I could imagine a bunch of people downsizing and compressing their originals without truly understanding what they were doing.

     
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  • Andrew Rodney
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    Feb 10, 2012 7:02 AM   in reply to Lee Jay

    Lee Jay wrote:

     

    Thomas Geist wrote:

     

    You think so? I'd assume that users employing the "Convert to DNG" dialog or using DNG converter are more of the savvy kind.

     

    Convert to DNG is essentially a way to destroy your originals.  I could imagine a bunch of people downsizing and compressing their originals without truly understanding what they were doing.

    Convert to DNG isn’t a way to destroy your originals until you define the way one converts to DNG. Prior to LR4, convert to DNG doesn’t destroy an original. It might destroy some proprietary metadata that only the manufacturers converter could use. The newer Lossy DNG conversion is a different story as pointed out, it is partially processed data.

     

    I’d agree it would be super dangerous on import if someone picked such an option without thinking (then yes, if they didn’t back up their original raws, it would destroy a lot of data).

     

    But the OP is also asking for a conversion on EXPORT. How is that dangerous? 

     
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  • Currently Being Moderated
    Feb 10, 2012 9:23 AM   in reply to Andrew Rodney

    Andrew Rodney wrote:

     

    But the OP is also asking for a conversion on EXPORT. How is that dangerous? 

     

    Conversion on export is the one we already have, and the one that isn't dangerous.

     

    We already agree about the one in Import (too dangerous).

     

    The Library - Convert Photo to DNG option is the one I'm referring to, and I think so was the OP (as well as the external converter).

     
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  • Currently Being Moderated
    Feb 10, 2012 11:28 AM   in reply to Andrew Rodney

    Right. I'm not into the whole lossy compression thing. I like the idea of making smaller raw files, but I want the megapixels which remain to be good megapixels.

     
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  • Currently Being Moderated
    Feb 10, 2012 11:32 AM   in reply to Mark Alan Thomas

    Mark Alan Thomas wrote:

     

    It could have two options, half size and quarter size, and produce a kind of sRAW file, turning 36 good megapixels into 18 and 9 super-megapixels, etc.

    Wrong math here.

    Half sized image will have two times smaller width and two times smaller height, so it will have four times less pixels compared to original.

    So 36Mp will give you 9Mp for half sized image, and 2.25Mp for quarter sized.

     
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  • Andrew Rodney
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    Feb 10, 2012 1:01 PM   in reply to Thomas Geist

    Thomas Geist wrote:

    That would be interesting and of course I absolutely second it: DNG with variable resolution but lossless compressed!

    Not sure that is possible. Maybe Eric can say. The lossless raw probably has to be rendered to be resized and I believe that is why you can now do this with the Lossly DNG in export.

     
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  • Currently Being Moderated
    Feb 10, 2012 1:06 PM   in reply to Mark Alan Thomas

    Mark Alan Thomas wrote:

     

    Right. I'm not into the whole lossy compression thing. I like the idea of making smaller raw files, but I want the megapixels which remain to be good megapixels.

     

    To get from raw data to lossy compressed DNG, you demsoaic and then compress with JPEG compression.  If you downsample, you do that first.

     

    The JPEG compression is efficient and of high quality (similar to PS JPEG level 10) so the loss associated with the compression is minimal.  Downsampling is a far larger loss of image quality.

     

    You'd be far better off with a lossy-compressed full-res file than a losslessly compressed down-sampled file of the same final size.

     
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  • Currently Being Moderated
    Feb 14, 2012 9:48 AM   in reply to Lee Jay

    I guess the appeal to me of pixel-binning (if that's the right term) a 36 MP raw file down to 18 or 9 MP would be in taking relatively soft Bayer-interpolated pixels and packing them down into fewer, but purer, pixels à la Foveon. You'd still be getting some of the resolution benefits of the initial capture having been 36 MP, but without the unnecessarily large sizes and processing overhead you get with the full size files. It seems to me that a 16 MP raw file generated from a 36 MP capture would be of higher quality than a native 16 MP raw file in terms of per-pixel quality.

     

    Or maybe this is just silliness.

     
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  • Andrew Rodney
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    Feb 14, 2012 11:07 AM   in reply to Mark Alan Thomas

    Mark Alan Thomas wrote:

    Or maybe this is just silliness.

    Don’t think it is silly, just don’t think it is possible on the non demosaiced data.

     
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  • Currently Being Moderated
    Feb 15, 2012 9:06 AM   in reply to Andrew Rodney

    That makes sense. I suppose I personally wouldn't care if the data had to be demosaiced first. When I think of the benefits of raw, I'm thinking about white balance and exposure and stuff like that, not whether the data has been demosaiced or not. At any rate, if if the pixels are being binned down to a quarter their size, they may as well be demosaiced first. To me this would still qualify as raw since I'd still be able to glean all the benefits of raw which are important to me. I wonder what Canon does to the raw files to yield its sRAW format. Have sRAWs been demosaiced?

     
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  • Currently Being Moderated
    Feb 15, 2012 10:57 AM   in reply to Mark Alan Thomas

    Mark Alan Thomas wrote:


    Have sRAWs been demosaiced?

     

    Yes.

     
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