Raw and DPP

[eikari]

Hello

I have had my 40D for little over a month, and for the first time I'm using Raw only. On the 10D I always used jpeg, and my policy then was not to change the original jpeg (always saved adjustments to a new file).

Since Raw is pretty new to me, I have a somewhat silly question. If I make changes to one of my Raw images in DPP (sharpening, colors etc) and saves it (not converting it, but saving it over the original CR2 file), can I open it later in DPP to ex. restore the image to it original state? In other words, is it possible to actually destroy/messing up the CR2 file using DPP?

Thanks in advance

Arild

 

[Michael Eckstein]

Yes you can. In the adjustment menu... the last item is revert to shot settings.
--
http://photo.net/photos/Michael%20Eckstein
http://meckstein.com/home.html

 

[Glenn W.]

Having used DPP for several years now... I was always a little annoyed that it allows you to write back to the RAW file... I always have to say "NO" when it asks if I want to save the changes I've made...

So, I did not know the answer to your question... but I just tried, and found that there is a 'Adjustments -> revert to shot settings' or 'Ctrl+Shift+Z' that does take it back to the original settings or Ctrl+Alt+Z 'Revert to last saved settings'...

I still don't like writing data to the RAW file... but I think it's more like the idea that I would not like the possibility that the file would get corrupt if/when I write to it... Ideally I'd like to save a copy to DVD before I start monkeying with the the RAW files I capture with my camera, however it's really just paranoia I think...

Hello

I have had my 40D for little over a month, and for the first time I'm
using Raw only. On the 10D I always used jpeg, and my policy then was
not to change the original jpeg (always saved adjustments to a new
file).

Since Raw is pretty new to me, I have a somewhat silly question. If
I make changes to one of my Raw images in DPP (sharpening, colors
etc) and saves it (not converting it, but saving it over the original
CR2 file), can I open it later in DPP to ex. restore the image to it
original state? In other words, is it possible to actually
destroy/messing up the CR2 file using DPP?

Thanks in advance

Arild

 

[Michael Eckstein]

So, I did not know the answer to your question... but I just tried,
and found that there is a 'Adjustments -> revert to shot settings' or
'Ctrl+Shift+Z' that does take it back to the original settings or
Ctrl+Alt+Z 'Revert to last saved settings'...

I still don't like writing data to the RAW file... but I think it's
more like the idea that I would not like the possibility that the
file would get corrupt if/when I write to it... Ideally I'd like to
save a copy to DVD before I start monkeying with the the RAW files I
capture with my camera, however it's really just paranoia I think...

Hello

I have had my 40D for little over a month, and for the first time I'm
using Raw only. On the 10D I always used jpeg, and my policy then was
not to change the original jpeg (always saved adjustments to a new
file).

Since Raw is pretty new to me, I have a somewhat silly question. If
I make changes to one of my Raw images in DPP (sharpening, colors
etc) and saves it (not converting it, but saving it over the original
CR2 file), can I open it later in DPP to ex. restore the image to it
original state? In other words, is it possible to actually
destroy/messing up the CR2 file using DPP?

Thanks in advance

Arild

It is not actually writing data to the raw file. It is just saving a recipe for the changes you have made to the raw file. A raw file cannot be changed and saved as a raw file.
--
http://photo.net/photos/Michael%20Eckstein
http://meckstein.com/home.html

 

[Michael Eckstein]

I still don't like writing data to the RAW file... but I think it's
more like the idea that I would not like the possibility that the
file would get corrupt if/when I write to it... Ideally I'd like to
save a copy to DVD before I start monkeying with the the RAW files I
capture with my camera, however it's really just paranoia I think...

I forgot to add; tthat is why raw files are sometimes used a evidence in court cases.
http://photo.net/photos/Michael%20Eckstein
http://meckstein.com/home.html

 

[HarryLally]

The original Raw file is not modified/ changed. It remains as a sort of digital negative. The changes you make are saved separately as a 'recipe' that will be applied the next time you open the file. But you can easily just revert to the original unmodified file at any time.

Michael

 

[eikari]

Thank you all!

I think it its time to change my setting on my camera from Neutral to Faithful. Was afraid to use other settings than Neutral in case of ruin the "negative".

 

[Glenn W.]

I believe you are wrong about this... Data is written to the RAW file, you can see this simply by looking at the Modified date of the CR2 file after saving a 'recipe' for that image... You can also tell this by the fact that the 'recipe' is saved somewhere and when working with CR2 files, there is no other file saved... move that file anywhere you like and that recipe goes along with it, it does modify the file.

Now, if your saying that it does not modify the data that represents what the sensor collected as the camera took the image, then I would not argue with that... However the fact that it does modify the file to some extent or another still bothers me, as the create data and modified date are no longer the same and anytime you write to a file and some of the data that makes up the entire file is most certainly changed.

There are other applications including binary editors that can easily modify any of the data that makes up a RAW file, you can easily replace the image data in a RAW file with a variety of programs.

RAW files by themselves are hardly worthy of 'evidence', unless maybe you pay for Canon's data verification kit and use it...

http://www.dpreview.com/news/0401/04012903canondvke2.asp

I still don't like writing data to the RAW file... but I think it's
more like the idea that I would not like the possibility that the
file would get corrupt if/when I write to it... Ideally I'd like to
save a copy to DVD before I start monkeying with the the RAW files I
capture with my camera, however it's really just paranoia I think...

I forgot to add; tthat is why raw files are sometimes used a evidence
in court cases.
http://photo.net/photos/Michael%20Eckstein
http://meckstein.com/home.html

 

[Glenn W.]

This is inaccurate information... the file is changed... Changes to the settings on a RAW file can be made with DPP. A recipe can be saved independently of a RAW file, but you can also save different settings directly to a RAW file using DPP. See my other post on this topic...

http://forums.dpreview.com/forums/read.asp?forum=1019&message=25303459

The original Raw file is not modified/ changed. It remains as a sort
of digital negative. The changes you make are saved separately as a
'recipe' that will be applied the next time you open the file. But
you can easily just revert to the original unmodified file at any
time.

Michael

 

[JimH]

When you allow DPP to "save changes" to your RAW file, the RAW file is rewritten. So if you're concerned about the potential for corruption due to a computer or hard drive fault, then it's worth knowing that the file IS rewritten in that case.

BUT, the RAW data that gets saved when you let DPP save changes by rewriting the file(s) is IDENTICAL to what you had to begin with. In other words, by design, the RAW data is never altered even though the file gets rewritten.

The reason the file must be rewritten is to let DPP alter the metadata that holds the most recent changes you've made to the processing recipe.

These Canon RAWs hold:

The actual RAW data (never changed).
The "as shot" processing settings (never changed).
The "most recent" processing settings (changed if you let DPP save changes).
And a bunch of EXIF data, the embedded thumbnails, and other goodies.

So the idea is that DPP (like all other RAW processors that I've ever used) DOES NOT change the RAW data. It does, however, give you the option of saving the "most recent" processing recipe into the RAW file itself if you allow it to do so.

I've never found my computer with DPP to ever corrupt a RAW file, but I suppose it's always a possibility that you'll have a glitch just as DPP is rewriting the RAW file.

This is why I prefer to always save a backup copy of every RAW file I shoot onto a separate drive. And further, I DON'T use any kind of automatic backup program that would automatically update my backups to reflect the latest state of each file.

That defeats the entire purpose of backing up if you allow a program to automatically replace your backups with the (possibly) corrupted versions found on your working drive, doesn't it?

So to make my backups, I simply copy the original RAW files to that backup drive every time I copy new files from a CF card to my work drive. I trust that a LOT more than some autobackup scheme that could potentially overwrite my precious backups with a corrupted copy of ANY file from my work drive.

--
Jim H.

 

[JimH]

DPP does not save the recipe as a separate "sidecar file" the way other RAW processors do. Instead, it embeds the "latest version" of your recipe directly into the RAW file if you let it do so.

This does not change the RAW data portion of the file, but it does need to rewrite the entire file to accomplish this. So if you're worried about hard drive or computer problems causing the file to be corrupted, it's worth thinking about this because you are reading, modifying, then rewriting the entire file (again, if all goes to plan, the RAW portion of the data in the file is NOT changed and I've never had any problems with this).

If I was a judge, lawyer, or juror on a case, I would NOT accept a RAW file as absolute proof of anything any more than I'd accept a JPG. I don't have this capability, but I'm sure someone could come up with a way to alter an image and then rewrite it back into a CRW format with the changes. This should not be too difficult of a programming task.

The only way I'd accept any digital photos as proof in a case where I think people would be motivated enough to do some altering of the files would be if they used something like this:

http://www.adorama.com/ICADOSKE3.html?sid=11930097881638037

...to add security to the captures.

This is why many police departments still use polaroids or disposable film cameras to record critical things and it's also why insurance companies often recommend that you just carry a disposable film camera in your car to document accidents rather than use your digital camera.

--
Jim H.

 

[GaborSch]

1. Saving the adjustments in a "recipe" file is very tiresome. However, this way you don't need to backup again the huge raw file, you can save the small adjustment file. Much more important: this way you can keep several versions of adjustments,

2. Saving the adjustments in the raw file always carries the danger of curruption. Though the adjustment parameters are placed after the original file (i.e. they are stored at the end of the new file), a small update occurs at the front of the file as well.

I do not know if the new file is a copy of the old one, or if the original file gets extended; probably the latter.

More important: if you want to maintain several versions, you have to keep several copies of the entire file. That sux.

Both ways suck. RSE/RSP showed how to do it. ACR sux too.

--
Gabor

http://www.panopeeper.com/panorama/pano.htm