# CR2 vs DNG



## Terry Rogers (Apr 6, 2015)

I've contemplated converting all my CR2 files to dng, and also converting on import. I know this is an old topic with the pros and cons debated on other threads, so I'm not too interested in that conversation here. Just wondering what most of you do.


----------



## lintoni (Apr 6, 2015)

The only time I use DNGs is as part of Magic Lantern's Dual ISO worhflow.


----------



## Marsu42 (Apr 6, 2015)

Terry Rogers said:


> so I'm not too interested in that conversation here. Just wondering what most of you do.



In that case: dng rulez :->


----------



## pwp (Apr 6, 2015)

It's too slow to convert all files to DNG on import with the sheer volume many photographers work with. Selects are converted to DNG, keyworded in Photomechanic then imported into LR. Once the job is delivered and approved, a month later all CR2's are dumped and the DNG's archived with the master files. Two copies, one on a five bay NAS and another on DVD. If I didn't dump the non-keepers I'd be utterly drowning in data.

Like many photographers around the planet, I'm following an adapted workflow in the book "The DAM Book" by the highly respected Peter Krogh. 

http://thedambook.com/about/
http://thedambook.com/blog/

FWIW in the interest of storage space optimization, some projects' DNG's are converted to much smaller lossy DNG's prior to archiving. Important job's DNG's are never crunched down to lossy DNG's. 

-pw


----------



## Diko (Apr 6, 2015)

Terry Rogers said:


> ... I know this is an old topic with the pros and cons debated on other threads...


 please could you provide links to old topics. I couldn't find those...

Thanks in advance.


----------



## eli452 (Apr 6, 2015)

If convert, why not after all changes are committed? Working with side cars files + CR2 is a lot easier than saving the entire dng file. When done do a batch convert on all/select files...


----------



## Berowne (Apr 6, 2015)

I converted some of the CR2 from my 70D to DNG simply to use older LR and PS-Versions with the new camera. I did a comparison (DNG and CR2 in diff. LR-Versions) and could not see significant differences in the result. So I can save money and use the old and much faster Program-Versions.


----------



## Zeidora (Apr 6, 2015)

The stripping of metadata in DNG is a serious downside of that format. Apparently, DNG is not an international standard yet (not ISO approved). I also read somewhere that DNG does not open in DxO; haven't tried that myself. The 20% or so less storage requirement is trivial considering hard drive sizes today.

Highly adjusted print files are stored as separate .tifs. Neither RAW nor DNG can accommodate all those changes (spotting, layers, layer masks, Lab-corrections, output USM, etc.).


----------



## Marsu42 (Apr 6, 2015)

Zeidora said:


> The stripping of metadata in DNG is a serious downside of that format.



There's no metadata stripped except the jpeg thumbnail of the cr2. Adobe stated that a dng->cr2 re-converter could be written to prove this fact. And if you peek with exiftool, surprise, the medadata is indeed the very same.



Zeidora said:


> Apparently, DNG is not an international standard yet (not ISO approved).



So what? Is .cr2 a standard?



Zeidora said:


> I also read somewhere that DNG does not open in DxO; haven't tried that myself.



Sure, dxo tries to block Adobe as the owner of the dng standard, that's the one reason pro optics doesn't support converted raw dng.

If you read up on it, the dxo come up with various contradicting statements not to give away the real reason; meanwhile they're perfectly happy to open "native" dng from other camera brands that don't have a go-between format like cr2.



Zeidora said:


> The 20% or so less storage requirement is trivial considering hard drive sizes today.



As the op wrote, this has been debated back and forth, but 20% is significant for some.


----------



## lintoni (Apr 6, 2015)

Marsu42 said:


> There's no metadata stripped except the jpeg thumbnail of the cr2.* Adobe stated that a dng->cr2 re-converter could be written to prove this fact*. And if you peek with exiftool, surprise, the medadata is indeed the very same.



I wish such a tool existed.


----------



## Zeidora (Apr 6, 2015)

Hi Marsu,

DNG is often touted as a non-proprietary, general-use format. This is not the case, it is an Adobe proprietary format. So one of the alleged advantages of DNG does not apply. The question then arises, why switch from one to the other?

Why DxO does not deal with DNG, I don't know. Could be due to Adobe or DxO. However, DxO is a widely used RAW converter, so the fact that it does not handle DNG is a problem.

As an other poster has pointed out, DNG -> CR2/NEF conversion is currently not available. Whether it would result in identical files (identical hash sum) is very much open. There is some discussion on whether or not DNG maintains all other metadata. 

I also wonder where the 20% file saving coming from. In digital information, there is no free lunch. That Canon and Nikon are needlessly bloating files seems unlikely.

The poll results are also quite clear. 75% or so use CR2 only, single digit percent used DNG only. And that is what OP was after.



Marsu42 said:


> Zeidora said:
> 
> 
> > The stripping of metadata in DNG is a serious downside of that format.
> ...


----------



## mackguyver (Apr 6, 2015)

Just to clear up some confusion:



> *Note*
> 
> Starting with version 10, DxO OpticsPro supports files converted to DNG in Lightroom or Adobe DNG Converter, for a more efficient workflow.



From: http://www.dxo.com/us/photography/community/tutorials/optimizing-your-dxo-opticspro-10-and-lightroom-workflow


----------



## sunnyVan (Apr 6, 2015)

I can't guarantee using LR forever. But I'll stick to Canon as long as it exists. So CR2.


----------



## RLPhoto (Apr 6, 2015)

I never got around to .DNG is simply the reason I didn't bother with the format.


----------



## drmikeinpdx (Apr 6, 2015)

During 2013 and 2014 all my CR2 files were converted to DNG as I imported them from the CF card into Lightroom. At the beginning of 2015, I re-evaluated this process and decided to skip the DNG conversion. I've been pleased with the increased speed of importing the files and so far, the CR2 files have not become obsolete. 

In my opinion, it's an additional burden on my time with a questionable future payoff. But that's just me.


----------



## pwp (Apr 7, 2015)

Diko said:


> Terry Rogers said:
> 
> 
> > ... I know this is an old topic with the pros and cons debated on other threads...
> ...


The abilities of the CR search function are modest to say the least. Use Google search. This was all debated ad-nauseum some years ago and I think the jury came back with the viewpoint that a DNG workflow is probably best. Read up in those links to Peter Krogh I posted.

-pw


----------



## Marsu42 (Apr 7, 2015)

mackguyver said:


> Just to clear up some confusion:
> 
> 
> > *Note*
> > Starting with version 10, DxO OpticsPro supports files converted to DNG in Lightroom or Adobe DNG Converter, for a more efficient workflow.



Unfortunately, this adds confusion as dxo doesn't support *raw* dng but simply demoisaiced dng which is essentially a tiff with better compression. As such dxo didn't really change anything, but simply created a fancy interface between pro optics and lr. But they certainly try to make it appear otherwise.


----------



## wyldeguy (Apr 7, 2015)

Due to using an older copy of LR and having the Canon 7D2 I am pretty much forced to convert all photos to DNG at import if I want to do anything with them. I'm a bit crazy so I keep the CR2 files as well in case something happens but I'm not smart enough/ have enough hard drives to keep them on a seperate drive so they all go in the same damn folder for search ability and to keep my pictures more organized.


----------



## Zv (Apr 7, 2015)

I don't convert to DNG. If somewhere down the line CR2 dies then I'll deal with it then. Don't need to add another step to my workflow. Sure, I'll lose my edits but this might be 20 or 30 years down the line so who knows what software will be capable of by then? Even now, reprocessing 4 year old RAW files on LR 5 makes a huge difference. Mainly through increased knowledge! 

Might save some of my best images as DNG using Lightroom on export to a secure place for archive purposes though. That might make sense.


----------



## Diko (Apr 19, 2015)

Diko said:


> Terry Rogers said:
> 
> 
> > ... I know this is an old topic with the pros and cons debated on other threads...
> ...


 Terry?


----------



## Rofflesaurrr (Apr 20, 2015)

What about automated hard drive backups? CR2 has the advantage here. When you make edits to photos in your Lightroom catalog, only the XMP sidecar files have to be updated on the backup drive. With DNG, all the DNG files need to be rewritten, which could add up to gigabytes of data and take significantly more time.


----------



## AshtonNekolah (Apr 20, 2015)

Terry Rogers said:


> I've contemplated converting all my CR2 files to dng, and also converting on import. I know this is an old topic with the pros and cons debated on other threads, so I'm not too interested in that conversation here. Just wondering what most of you do.



I convert all to DNG, no loss of quality and files are smaller for more drive space. I also find using DNG files faster I have the same options as if i where to use CR2.


----------



## Mt Spokane Photography (Apr 20, 2015)

I've read all the comments about DNG and CR2, and gave it a try. I found it was a pain to use, but like all new things, I could overcome that. I see DNG as more likely to go away than CR2, simply because of the very few users. In either case, edits will not be lost, since old software versions will not simply go away.

We will never see a DNG as a standard included on major camera companies cameras for a simple reason. It eliminates any possibility of new features than need a change in the format. A company would have to reveal their intentions of releasing new features to a industry committee and wait 5-10 years for a revision. A few smaller camera companies do write to DNG. This means their hands are tied as far as any improved formats. Its probably a economic reason, since they cannot afford to develop a new format in any event.

Both formats are heavily compressed, but as long as lossy compression is not used, they will have the same image quality.


----------



## tpatana (Apr 20, 2015)

What would be benefit of the conversion?

All my storing is in cr2.


----------



## Maiaibing (Apr 20, 2015)

If you shoot different platforms (Canon/Nikon/SONY) DNG may - may - make sense.

Otherwise you're just betting on a digital picture format that is used by very, very, very few people and does not have the ability to integrate directly with internet viewing. Smart?

Apart from that DNG throws away some of the metadata - enough reason for me not to use it as I would always have to store both types of files anyway.

As someone else said earlier if CR2 fades away we can very easily deal with it then. However, there is no way back from DNG to the original RAW.


----------



## Terry Rogers (Apr 26, 2015)

Diko said:


> Diko said:
> 
> 
> > Terry Rogers said:
> ...



http://www.canonrumors.com/forum/index.php?topic=24309.0

I may have been thinking of other forums/web sites, but it was discussed on the above linked thread


----------



## dolina (Apr 26, 2015)

There will always be a tool to convert a certain file type to another when it falls too out of favor.

But according to the father of the internet the surest way to keep your images is to print them


----------



## Mt Spokane Photography (Apr 26, 2015)

dolina said:


> There will always be a tool to convert a certain file type to another when it falls too out of favor.
> 
> But according to the father of the internet the surest way to keep your images is to print them



Print them in B&W, color fades too soon. I'm not certain that inks in use will last either. There are simulated tests done with bright light over a period of days or weeks and then extrapolated to 100 years or so, but no one has actually had a print stored using recent technology, so some unexpected factor might make them go away. Silver Halide printing technology has pretty well went away as well, its proven to last.


----------



## zim (Apr 27, 2015)

This is perhaps getting a little off topic, well maybe not as those files whatever format have to be stored somewhere! what would you all consider the best media to store files for say;

100 years

1000 years

Regards


----------



## dolina (Apr 27, 2015)

zim said:


> This is perhaps getting a little off topic, well maybe not as those files whatever format have to be stored somewhere! what would you all consider the best media to store files for say;
> 
> 100 years
> 
> ...


Are you forecasting to live that long? Do you think people 1,000 years from now will care about your cats and selfies? 

I wouldnt store them in HDD that's for sure. I almost lost my my library from 2010-2012 in a HDD i left in cold storage since 2012. Good thing after a few hours left turned all the data became accessible.

I know tape drives could be an option and is an option for corporate backups.

http://time.com/3710227/google-vint-cerf-digital-dark-age/


----------



## Mt Spokane Photography (Apr 27, 2015)

zim said:


> This is perhaps getting a little off topic, well maybe not as those files whatever format have to be stored somewhere! what would you all consider the best media to store files for say;
> 
> 100 years
> 
> ...



Right now, from the remarks of experts, you will have to depend on someone converting the images to new media as the old becomes out of date and the ability to read it is no longer available. Trying to run a RLL hard drive from the early days is already a difficult thing to find, and it requires a isa slot. In another 25 years they will be virtually extinct. Its already difficult to find a reader for those early 8 inch floppies.

I've seen some who say that the hard coated "M" disks will last for 100 years, but they have only been around for a short time, so it could be wishful thinking. For sure, all my early CD's that I wrote data to have lost all the data. Some fairly recent DVD's are no longer readable. (I just spent 2 weeks copying 400 DVD's to my new NAS and found a dozen that were now trash). I had switched from Sony and TDK to Verbatim Brand, and the Verbatim DVD's were all good). I have quite a few of the Gold Kodak CD's that are over 15 years old that I also need to test.

My DVD reader/ writer died during the process of transferring my DVD's to the NAS, so I almost bought a new Blu Ray writer that could write to the newer "M" Blu-ray disks, but found a good unit in one of my recently dead pc's. It is a light scribe unit, something else that is no longer around. I have a bundle of light scribe disks as well. That technology was so slow and klunky that I never used it, a Sharpie works fine. I have used my Epson printer to print on DVD's and that made some nice ones.


----------



## Marsu42 (Apr 27, 2015)

zim said:


> 1000 years



Your best bets are edging stone tablets (though not more than 10 commandments might fit) or writing papyrus - the latter is surprisingly effective as ancient Egypt has proven, there's no acid in it unlike modern paper.

For larger amounts of data, be happy we're all very mortal and the storage problem ensures we won't burden future generations with heaps of digital crap data. To me, actually this is a rather calming perspective.


----------



## zim (Apr 28, 2015)

Mt Spokane Photography said:


> zim said:
> 
> 
> > This is perhaps getting a little off topic, well maybe not as those files whatever format have to be stored somewhere! what would you all consider the best media to store files for say;
> ...



Thanks MSP that's interesting and useful practical info, the question actually stems from a conversation I was having in the office regarding information that requires a very long archival time, although probably not 1000 years! we have been looking at options and one does actually say that long though, I was a tad sceptical, given the depth of knowledge on this site it seemed like a good idea to ask opinion

Thanks again
Regards


----------

