[Rusty]

Thanks for that Richard.

Do you have a link to the original diagrams?

Cheers,
Rusty

[flyer]

Do you have a reference to back up that claim ? This is the first time I've read anything of the sort.

My understanding of things is that the K10D's raw files (as those of most other cameras, BTW) do NOT actually contain any color information whatsoever, but only the luminance of each photosite under the "RG/GB" bayer array. Converting *that* into regular RGB (and therefore into a color gamut) is performed by the raw converter. Therefore, I don't understand how DNG could have a wider color gamut than PEF...

I have been printing for 35 years and owned a printing business with my brother for the last 25. We have a digital set up that could shame just about any photographers, and, although I'm not the digital expert in the shop, we do employ two full time graphic artist. I got those info from those two "computer nerds".

[flyer]

DNGs & PEFs contain exactly the same image info. Colour gamut is a function of the conversion, not the format of the data container.

dave

EDIT: oops, typing at the same time as *isteve..

The information gathered by the sensor is the same. The way it is stored on the SD card is different. If it was the same, there would be no need to put the two standards in the camera's menu!

[distudio]

The information gathered by the sensor is the same. The way it is stored on the SD card is different. If it was the same, there would be no need to put the two standards in the camera's menu!

That doesn't mean that the reconstructed RAW data will differ as the compressed PEF uses lossless encoding.

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Last edited by distudio; 03-20-2008 at 04:59 PM.

[*isteve]

I have been printing for 35 years and owned a printing business with my brother for the last 25. We have a digital set up that could shame just about any photographers, and, although I'm not the digital expert in the shop, we do employ two full time graphic artist. I got those info from those two "computer nerds".

If you said 8 bit JPEG vs 16 bit TIFF then your "nerds" would be correct. The latter has smoother colour gradations because it has more colour values it can use to describe minute differences in shades.

The only reason why Pentax included DNG is to allow you to exploit RAW converters that do not recognise PEF files, and it will also be nice in 20 years when you cant find a RAW converter that works with your old files. Also, probably because Samsunbg needed it (they have no other RAW format).

They included PEF because they can compress it (noone has access to the compressed DNG format from Adobe). Its nice to have the choice.

However if your "nerds" think there is any difference in output quality they are totally mistaken. The data stored in the two file formats is identical.

[distudio]

They included PEF because they can compress it (noone has access to the compressed DNG format from Adobe).

Just for the record the DNG spec indicates that JPEG lossless compression may be used for Compression of raw image data, the rumour that Adobe has denied access to the DNG compression algorithms is simply untrue. I suspect the compression engine used in the Pentax DSLRs is simply optimised to handle the compression method applied to the RAW data TIFF in their PEF format and isn't suitable for DNG compression for one reason or another.

[procyon]

Just for the record the DNG spec indicates that JPEG lossless compression may be used for Compression of raw image data, the rumour that Adobe has denied access to the DNG compression algorithms is simply untrue. I suspect the compression engine used in the Pentax DSLRs is simply optimised to handle the compression method applied to the RAW data TIFF in their PEF format and isn't suitable for DNG compression for one reason or another.

Most likely DNG compression is more advanced than PEF compression and would require a faster processor to shoot at the same speed. I doubt anyone would want to pay more money to get compression for both formats.

[jaws]

I am far from an expert and need others to direct me to the best format, I note that Scott Kelby in his CS3 book states that 'when you choose DNG in the save options the compressed (loosless) checkbox is turned on (which is fine as lossless means no loss of quality)' and also his reasoning is to ensure that in ' 5-10 years time maybe camera companies wont support or will change format therefore you would be unable to open a specific camera companies Raw files"
So I am saving files in DNG is this wrong or should I be saving in PEF?

cheers,
John

[Rusty]

Check out this authoritative article on the subject.
PENTAX digiich


His last comment right at the bottom of the text with the blue background is:
"Based on what I have described, I can’t find any particularly compelling reason to choose DNG as a RAW-data file format over a manufacturer-specific format like PEF."

Interesting stuff.

Rusty

[rfortson]

For printing needs, DNG is the preferred file because of it's wider color gamut. Otherwise, for day to day operation, you won,t see much difference.

I process my PEFs in Pentax Photolab, and I have the choice during processing of which color space I want to use, sRGB or Adobe. Therefore, I don't see how there's any difference between the PEF and DNG.

[attack11]

The information gathered by the sensor is the same. The way it is stored on the SD card is different. If it was the same, there would be no need to put the two standards in the camera's menu!

pef is a proprietary format, dng is an opensource format. that's the difference.

[123K10D]

I'll track down the article tomorrow, but it was from a paragraph from an interview with the head engineer of Pentax, during a discussion about the demise of the full frame project and just prior to the release of the K20D.

He specifically stated that PEF contains marginally more information from the sensor, than DNG. Flies in the face of everything else around, but it's a direct statement from the man who actually would know.

For the record, I shoot DNG, for Adobe compatability.

[distudio]

I'll track down the article tomorrow, but it was from a paragraph from an interview with the head engineer of Pentax, during a discussion about the demise of the full frame project and just prior to the release of the K20D.

He specifically stated that PEF contains marginally more information from the sensor, than DNG. Flies in the face of everything else around, but it's a direct statement from the man who actually would know.

For the record, I shoot DNG, for Adobe compatability.

A comprehensive thread about this very report exists on DPR:

Re: DNG on camera contains less info than PEF: Pentax SLR Talk Forum: Digital Photography Review

[Ishpuini]

For me it's simple. I shoot PEFs because they are smaller than the DNGs out of the camera. The RAW image info in these files is the same, and that's what matters. If PEFs mean I can fit more images onto a card, that's what I want when I'm in the field shooting. For studio work this may not be such an important consideration.

The only exception is with a new camera. Since Lightroom (my preferred PP tool) mostly does not support the PEFs from the start (got both my K10D and K20D before Adobe supported their PEFs) I start out with the large DNGs. Once support is there, I switch to PEFs!

Note that I do not archive my PEFs!! I convert them to losslessly compressed DNGs upon import in Lightroom. Those are even smaller, so that saves disk space.

Note I don't really worry about the actual storage space or even the cost of it. It's just more practical to have smaller files to work with...

Wim

[baw]

pef is a proprietary format, dng is an opensource format. that's the difference.

Whatever DNG is, it isn't Opensource. It is controlled by Adobe, and they haven't published all specs.
Have a look at this page for two interesting opinions on DNG.