The Shrinking M8 Files

[roccoriley]

I have several questions having to do with the D8 DNG files.

1. What does the Adobe DNG converter do?

2. Why do my 10.2 Meg D8 DNG files shrink to 6 Megs after processing by the Adobe DNG converter.

3. What are the differences between the different DNG files, I thought Adobe's objective was to provide a standard portable format for all digital negatives but if there are different formats then that objective has not been achieved.

4. If the Leica M8 DNG files are being processed by the Adobe Converter and are losing 40% of their bytes then are we losing critical image information when we convert using this converter?

5. Should we be archiving the original M8 DNG files insted of the files that are produced by Adobe DNG converter?

As you can tell, I am new to the Leica M8 world!!

[RSL]

Originally Posted by roccoriley

I have several questions having to do with the D8 DNG files.

1. What does the Adobe DNG converter do?

2. Why do my 10.2 Meg D8 DNG files shrink to 6 Megs after processing by the Adobe DNG converter.

3. What are the differences between the different DNG files, I thought Adobe's objective was to provide a standard portable format for all digital negatives but if there are different formats then that objective has not been achieved.

4. If the Leica M8 DNG files are being processed by the Adobe Converter and are losing 40% of their bytes then are we losing critical image information when we convert using this converter?

5. Should we be archiving the original M8 DNG files insted of the files that are produced by Adobe DNG converter?

As you can tell, I am new to the Leica M8 world!!

1. The DNG converter simply compresses the file. If you're using it with any other format, such as .NEF, it converts the other format to DNG and compresses it. You don't have to use compression, but it's lossless, so why not?

2. Because they're being compressed with lossless compression.

3. There isn't any noticeable difference. Some earlier DNG files were slightly different, but DNG is backward compatible. Leica may be adding some stuff to the M8 DNG files, since DNG allows that, but, in essence, DNG is DNG, just as parts is parts.

4. You're not losing any information, critical or otherwise. The M8 does a whirlygig non-linear compression of some of the high data to 8 bits, but the resulting file is difficult, if not impossible, to tell from full "16 bit" files.

5. That's up to you. I can't think of a good reason to hang on to the originals, but maybe someone can come up with one.

[adan]

The purpose of the DNG converter is to convert non-DNG-format RAW files (Nikon NEF, Canon RAW, Sony SR2, etc.) to the DNG format. Since the files straight from the M8 are ALREADY DNGs, why would you want to use the convertor with them? Seems redundant.

I haven't used DNG Converter since I switched from the Sony R1 to the M8 - I just open the files from the M8 directly in Adobe Camera Raw or Capture one or whatever.

[sean_reid]

Originally Posted by adan

The purpose of the DNG converter is to convert non-DNG-format RAW files (Nikon NEF, Canon RAW, Sony SR2, etc.) to the DNG format. Since the files straight from the M8 are ALREADY DNGs, why would you want to use the convertor with them? Seems redundant.

I haven't used DNG Converter since I switched from the Sony R1 to the M8 - I just open the files from the M8 directly in Adobe Camera Raw or Capture one or whatever.

Hi Andy,

The main reason might be to compress them easily and quickly.

Cheers,

Sean

[ho_co]

R--
Remember, there are two design standards for DNG.

Leica was the first and so far only company to use the second version, which includes a lookup table.

A big part of what the DNG converter is doing is removing the lookup table and storing the actual value for each pixel rather than a pointer to the point in the LUT where the value is stored.

To me it would be more logical for Leica to have stored the actual value in each location rather than a pointer to where the value is stored, but if they had done that with their compression scheme, apparently it would no longer have matched the DNG specification and would have been considered a RAW file that needed its own RAW conversion algorithm.

Or maybe they knew they'd be getting enough flak for producing a 10 meg DNG and decided that was better than trying to explain a 6 meg version.

You're saving all the data that were there to begin with, just compacting them to fit into a smaller space.

--HC

[roccoriley]

Thank you all very much for the information.

Incidentally, Lightroom users can perform this conversion automatically on import, if preferred.

[bsmith]

Originally Posted by adan

Since the files straight from the M8 are ALREADY DNGs, why would you want to use the convertor with them? Seems redundant.

.

to see full size previews in photo mechanic and other editing apps.

btw They don't shrink in size if you don't select compression. (they are actually larger with the large preview option)

[yadillah]

If DNG is DNG, then why do some programs open the M8 files and others don't.
I use ACDsee, and, although my version is the latest, and it is set to recognise DNG files, it will not open those from the M8. I cotacted ACDsee about this and was told that their ACD pro does not recognise files from the M8. They said that future updates would.
This means that all DNG files are not the same, and that the M8 files are not as universal as we are led to believe.

[bsmith]

Originally Posted by yadillah

This means that all DNG files are not the same, and that the M8 files are not as universal as we are led to believe.

Yes

[isaac]

Hello!

Originally Posted by yadillah

If DNG is DNG, then why do some programs open the M8 files and others don't.

Some programs are DNG reader, some programs are only reader of special DNGs.

I use ACDsee, and, although my version is the latest, and it is set to recognise DNG files, it will not open those from the M8. I cotacted ACDsee about this and was told that their ACD pro does not recognise files from the M8. They said that future updates would.

The developer of this application has not implemented the standard (ISO), he has only implement those, he knows about some DNGs...

This means that all DNG files are not the same, and that the M8 files are not as universal as we are led to believe.

M8 DNGs follow 100% the standard, but some (and also expensive) applications have only a SUBSET of the standard implemented!