DNG vs TIFF

[Bob Bryer]

I've been using DNG files (Pentax K-5) for HDR panos. I am confused about the discussions of RAW/DNG vs TIFF for PTGui HDR. Since DNG is an ADOBE format based on TIFF I was expecting them to be equivalent.

Is Tiff better than DNG?
If so is ADOBE RAW as good a converter you can use since DNG is ADOBE standard?
If not ADOBE RAW, what is the best DNG to TIFF converter?

Thanks
Bob Bryer

[awi]

Hi Bob,

DNG is sort of a container that can hold different file types, Raw,
Tiff, Jpeg.

Adobe is trying to make it a standard container for all Raw file
types.

Adobe Raw converter is OK, but I prefer DXO for lens corrections, or
CaptureOne for general workflow.

Andre

[Erik Krause]

Am 13.05.2012 14:38, schrieb Bob Bryer:
> I've been using DNG files (Pentax K-5) for HDR panos. I am confused
> about the discussions of RAW/DNG vs TIFF for PTGui HDR. Since DNG is an
> ADOBE format based on TIFF I was expecting them to be equivalent.

TIFF and DNG are both container formats, but that's all they have in common.

> Is Tiff better than DNG?

They contain totally different things. DNG is a container for raw image
data and TIFF is a container for developed images. DNG is good to
archive your images. TIFF is good to process them.

It is no good idea to use DNG directly in PTGui since you loose most
advantages of shooting raw if you do that. For HDR you might even get
better results if you shoot jpeg instead.

--
Erik Krause
http://www.erik-krause.de

[Kevin Wilton]

E

> Is Tiff better than DNG?

This is how I understand it. It might not be 100% correct but this
explanation makes more sense to me that the container thread that is going
on here, at the moment... Maybe it will help others, too.

A DNG is Adobe's attempt to unify the RAW format. Since digital cameras
started using RAW there have been over 160 variants and only about 40 are
still supported. Imagine only two years ago you bought one of the new
whiz-bang Contax cameras thinking you were buying into some sort of
longevity then you will already know that's not the case and be very
disappointed.

It seems that camera designers make cameras and then have their software
guys sort out the format, which means that every new Canon, Nikon, Fuji,
etc. has a new variant of the NEF, CR2 or RAF. Even though the file
extension doesn't change, the RAW file behind it most definitely does. As a
result, Adobe has had to regularly bring out a new CameraRAW engine to
incorporate each new camera format. Also, each time there is a new format,
CameraRAW drops some of the older formats off the end of its conveyor belt.
If it didn't do this, the CameraRAW engine would be huge by now and would
have to continue to grow.

Anyway, the data contained within all of the RAW file formats also contains
proprietary information from the manufacturer as well as camera specific
information that is not required to produce the actual image. The DNG
converter strips away this 'extra' information and reduces the data in the
Adobe DNG format to just that required to export a final result, after
completion of any and all processing in whatever converter you choose to
use.

Pentax, in their infinite wisdom, have deliberately chosen to use for their
camera RAW format the DNG, which makes absolute common sense really, when
you think about it because Adobe will always support their own file system,
even while they no longer feel any obligation to support the older ones.

So, the remaining data information within the new DNG is essentially only
the old data information from the NEF, CR2, RAF, etc. that is needed for the
production of the image, and nothing more. That said, it is still a RAW file
format made of DATA, NOT based on a TIFF because that is PIXEL information.
There are NO pixels in a RAW/DNG, not until an image has been exported or
'saved-as', once opened into Photoshop.

The 'image' you see in your chosen RAW filer converter is not really an
image at all. You are not making changes to any pixels, you are not even
making changes to the RAW file either, these are read only. When you see an
'image' in your chosen converter, whether ACR, Lightroom or whatever, you
are merely looking at a PREVIEW of the image that WILL be produced ONLY when
you export one, or perform a save-as.

>They contain totally different things. DNG is a container for raw image
data >and TIFF is a container for developed images. DNG is good to archive
your >images. TIFF is good to process them.

So is it better to archive a DNG and do your processing on a TIFF, the
answer has to be NO.

NO pixelated image is better than a chunk of infinitely malleable RAW data.
Any adjustments you make to that TIFF are destructive. You cannot create
information except at the time you press the shutter button. Any changes you
make to a TIFF thereafter can only be destructive. The changes you make to
your TIFF may well achieve the visual effect you are after but pixel
information would have to have been sacrificed in the process. Think about
it, you are not creating information, you can't, therefore, if you make any
changes to a TIFF, you must be destroying some in the process of that
change.

Are you destroying information with a RAW/DNG process? No, never, the file
is read only. You make the changes you wish to make in your converter and
then, ONLY then produce pixels in a brand new file that, should you make any
further changes, are then only destructible. That's why you can delete the
XMP file and your RAW would have reverted to its original form.

Frankly, and I am not a Luddite here but while I see that some people will
prefer to have all of their work done by a single piece of software, there
are better RAW file processors out there as well as better HDR software. If
you really are concerned about quality, batch process your raw images in
your converter to the maximum extent that you can. Then batch produce a
series of HDR images in your HDR processor. Only then, when perfectly happy
with these, create your new pano. Is this a more long winded process, for
sure it is. Does it produce a better result, only you can really decide. Is
your work important to you? Only you can decide that as well.

Is this any help?

Kevin

[UtahBob]

On May 15, 7:25 pm, "Kevin Wilton" <wil...@eeek.tv> wrote:
>>
> So, the remaining data information within the new DNG is essentially only
> the old data information from the NEF, CR2, RAF, etc. that is needed for the
> production of the image, and nothing more.

I'll add for those who might be distraught at the aspect of a loss of
original information that there is an option to embed the original raw
file in the DNG. It blows up the file size but eliminates the need to
archive the raw in addition to the DNG for those who want to hold on
to the camera file. In Lightroom for instance it's as simple as
selecting a checkbox in preferences. IMO DNG is the way to go.

Bob

[Kevin Wilton]

B

You're correct and I neglected to mention that because, and for no other
reason, I forgot all about it. I now trust the DNG 100% and don't feel the
need embed the RAW. That said, for quite a long while, and this might be a
much better option, I did store the RAW in a separate folder on the hard
disk, on the just in case principle...

I never embedded them because, as it turned out and I was happy with DNG,
getting the RAW back out of the DNG would have been a proverbial pain to
do...

In the end, when I was totally confident, I simply deleted the RAW file
folders. Now I just use Lightroom to copy my files direct from my card into
my workflow as a DNG. The RAW files never leave the card and with four,
numbered 1-4, I can rotate the cards to give me a bit of a short-term
back-up until I use that card again and format it, in four shoots time.

K

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[Ken Warner]

I've never thought of reading my Sony .arw files directly off my card into DNG via Lightroom.

That sounds like a sensible workflow but wonder if I loose any image quality.

Does anyone have any opinion or concern about any disadvantage of direct conversion of .arw into DNG????

[Kevin Wilton]

K

All I can say is I have had no issues with the NEF files of my D700 and for
the short while I was over on the dark side, my CR2 files from the 1DS MkII
were also fine.

K

-----Original Message-----
From: pt...@googlegroups.com [mailto:pt...@googlegroups.com] On Behalf Of

[Philippe Laporta]

Hi guys, I was looking up some info on this same subject and found this post to be the clearest and most instructive. I have another related question to the choice between native RAW and DNG.

The issue is that of backing up images.

Unless there is a way around it, I find it long and time-consuming to backup DNG files that have been modified, compared to native RAW.  

With the native RAW, one can decide to create very small (kb) sidecar files that change without the main file changing at all.

From what I understand the sidecar is integrated within the DNG file, leaving the native information untouched, but then the backup is done on the complete DNG file (10 to 20 MB instead of 10-15 kb). 

I regularly go back in me older images of various trips and when I then do a backup on changed files only, it basically backs-up the sidecar file because the RAW file has not changed.

If you know of any way to split-out the sidecar from DNG, I would gladly convert all my RAW files to DNG

Please confirm this is right

and please tell me if there is a way to get sidecar files with DNG.

Thank you, Phil