Adobe Digital Negative

[DonLashier]

> Well I believe it's step in the right direction.

I do too, but I doubt that most manufacturers will embrace it except perhaps for the consumer models. Taking a brief look at the specs, they already look too constraining not handling new technologies already existent like specials sensors with extended dynamic range. These of course could be handled in the demosaiced form but then you may be giving up a lot of the flexibility of shooting raw. But kudos to Adobe for trying, and for returning us to a standard (TIFF) file format! Different extension so the klutzes won't get confused, but using TIFF format should make it easy for image browsers to show the thumbs and some metadata by just treating DNG's as TIFFs.

- DL

[DavidPlummer]

[ QUOTE ]
they already look too constraining not handling new technologies already existent like specials sensors with extended dynamic range

[/ QUOTE ]

Just curious Don as to why you think the specification is constraining for new technologies such as different pixel arrangements and dynamic range? The TIFF and supporting specifications provide a number of schema's for pixel arrangement and there is no reason to assume that they couldn't be extended. The limitations on dynamic range are only limited by the development and inclusion of compression schemes above 16-bit.

It would be nice to see camera manufacturers move towards this specification, as it is broadly similar to the CR2 Canon format there is no reason for them not to include an option to output files in the DNG format. Though I would expect the file size for a Canon 'in camera' generated DNG file to be larger owing to the need to store a large & small thumbnail as per the current CR2 files (Adobe generated DNG files only have a 212pixel thumbnail for compatibility with PS, CR2 file as 1500pix thumbnail to comply with design rules for camera spec).

[RobertEdwards]

[ QUOTE ]
Adobe generated DNG files only have a 212pixel thumbnail for compatibility with PS, CR2 file as 1500pix thumbnail to comply with design rules for camera spec.

[/ QUOTE ]
Ouch! 212 pixels is too small for an embedded thumbnail. Many applications use the embedded thumbnails for fast display, such as Photo Mechanic and iView MediaPro. I'd like to see DNG make embedded thumbnails the same size as the original.

-- Robert.

[Ethan_Hansen]

-> Ouch! 212 pixels is too small for an embedded thumbnail. Many applications use the embedded thumbnails for fast display, such as Photo Mechanic and iView MediaPro. I'd like to see DNG make embedded thumbnails the same size as the original.

Yes indeed. The DNG specification states the thumbnails must be "as described in the TIFF-EP specification." Following the specs, the TIFF-EP spec state the maximum allowable thumbnail size is 256x256 pixels. The larger thumbs cameras offer make for fast views that are actually useable - 256 pixels isn't enough to judge much other than rough composition.

[DonLashier]

> Just curious Don as to why you think the specification is constraining for new technologies such as different pixel arrangements and dynamic range? T

David, maybe I overlooked something but I see no provision for more than the classic RGB bayer mosaic. This would leave out sensors such as the Sony 4 color chip and the Fuji extended dynamic chip. True, these could be handled by extensions but soon we're back in the proprietary quagmire with perhaps an additional layer of obfuscation added (or not, depending on how well the standards are defined and followed). A lot of this depends on whether sensor design settles on the common RGB-bayer method or whether it diverges in attempts to extend dynamic range etc.

Frankly I think that a defined standard for storing the data is desirable despite these possible issues. In general it can only make things easier for everyone involved although I find it a bit distressing that Adobe has chosen a color calibration model that favors their "method" perhaps hoping to get the camera manufacturer's to do their legwork. I doubt the manu's will bite on this part of it, and I actually doubt that they'll bite at all (well, ok, maybe Olympus [img]/ubbthreads/images/graemlins/grin.gif[/img]). Even if they don't the standard may be of some use for archival purposes given Adobe's providing a conversion utility.

- DL

[RobertEdwards]

Don while I too have reservations about camera manufacturers embracing DNG, the archival conversion appeals to me. Thomas Knoll said it was possible to convert raw camera formats to a new file format which converters could process, specifically ACR. I hoped this new format would be open source and suitable for archiving like tiff, but retain the options that make raw files appealing, such as modifying white balance.

So if camera makers ignore DNG I expect software vendors will seize upon it. Using Adobes DNG fast converter I can archive all the flavors of Nikon's NEF. Then my dream is all image browsers, asset managers, printers and raw converters will read this one standard format.

-- Robert.

[Thomas_Knoll]

"Yes indeed. The DNG specification states the thumbnails must be "as described in the TIFF-EP specification." Following the specs, the TIFF-EP spec state the maximum allowable thumbnail size is 256x256 pixels. The larger thumbs cameras offer make for fast views that are actually useable - 256 pixels isn't enough to judge much other than rough composition."

The DNG specification supports any number of thumbnails/previews, at any sizes. The TIFF-EP specification is talking only about the size limitation of the *first* thumbnail.

The current version of the Adobe DNG Converter is only saving 256 pixel thumbnails, but that is absolutely not a limitation of the DNG format.