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02-09-2009, 12:34 PM   #1
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K20d... PEF or DNG?

The K20d offers both RAW formats...

Any preferences for one or the other? Any advantages to using DNG?

Thanks!

Pat

02-09-2009, 12:53 PM   #2
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The DNG is probably more widely supported but I prefer PEF because it's a little smaller. PEF is supported by everything I use but it can be converted to DNG if necessary.
02-09-2009, 01:04 PM   #3
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Yes, I agree with Golden.
02-09-2009, 01:53 PM   #4
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Seems someone made some tests on a k10, and curiously, the DNG has more "unused" pixels than PEF...
So that's a point to check on the k20 to choose between the two...

02-09-2009, 02:06 PM   #5
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I shoot DNGs for what is probably all the wrong reasons. I was able to find a plug in that thumbnails DNG files in Windows, I haven't found one that does the same thing for PEF files.
I also have a hunch that in the long haul, DNGs will be better supported than PEFs, but this is just a hunch.
02-09-2009, 02:21 PM   #6
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DNG has a larger color gamut. With a good printer, you'll get better results with DNG if you know how to use it correctly. You can convert PEF to DNG, but you'll get the same gamut as PEF , since you can't stretch the color gamut once it is recorded. If you only keep your pictures on the computer and don't have high quality prints made, then you won't see a difference. As for the gamut, if you think one is as good as the other, ask any printing business what is best for them to work with.
02-09-2009, 02:48 PM   #7
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QuoteOriginally posted by flyer Quote
DNG has a larger color gamut. With a good printer, you'll get better results with DNG if you know how to use it correctly.
Hmmm, that's news to me but it might explain the larger DNG file size. Can you tell me where you dug up that nugget of info? I would like to look into that assertion a little further. Thanks!
02-09-2009, 03:46 PM   #8
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QuoteOriginally posted by GoldenWreckedAngle Quote
Hmmm, that's news to me but it might explain the larger DNG file size. Can you tell me where you dug up that nugget of info? I would like to look into that assertion a little further. Thanks!
I'm a printer. I've had my business for 22 years and worked in the trade for 35 years. The larger DNG file is because it is uncompressed as the PEF file has loss less compression applied to it. If you work with the CMYK color space, you will find a rather interesting difference between the two color space, especially toward the deep blues and reds. For the web, you are better off with the PEF color space, as the DNG will look more muted since the computer screen can't reproduce the larger gamut.

02-09-2009, 03:55 PM   #9
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Same here...

I've had this in mind for a long time too...
but so far I always save in PEF format.
02-09-2009, 04:01 PM   #10
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QuoteOriginally posted by flyer Quote
I'm a printer. I've had my business for 22 years and worked in the trade for 35 years. The larger DNG file is because it is uncompressed as the PEF file has loss less compression applied to it. If you work with the CMYK color space, you will find a rather interesting difference between the two color space, especially toward the deep blues and reds. For the web, you are better off with the PEF color space, as the DNG will look more muted since the computer screen can't reproduce the larger gamut.
Hold on there buddy!

The Pentax K10/K20 can only shoot with two gamuts sRGB or aRGB It knows nothing of CYMK or printing for that matter. Raw files whether PEF or DNG do not know about any colorspace except for the preview image which defaults to sRGB if not specified.

PEF is not a colorspace at all and it is just another linear encoding method for storing the data directly from the sensor. It doesn't print or display any different than DNG.

PEF is compressed in camera using a lossless JPEG compression algorithm. The key word here is lossless! That means it can be uncompressed into the original data without any lost data. DNG in camera is not compressed and hence has the exact same data as the uncompressed PEF. DNG files can be compressed using the same JPEG lossless compression as PEF, Pentax chose for whatever reason to not do that in camera.

The differences you claim have nothing to do with whether or not the picture was stored in PEF or DNG, but rather what colorspace was applied during processing of the raw files and how they were processed.

Let's not misinform people about what PEF or DNG is or isn't.
02-09-2009, 04:40 PM   #11
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QuoteOriginally posted by ve2vfd Quote
The K20d offers both RAW formats...

Any preferences for one or the other? Any advantages to using DNG?

Thanks!

Pat
One thing I can tell you is there no PEF codec software for 64-bit Windows. Which means on my Vista x64 machine, the only program I can use to manipulate PEFs is Pentax Photo lab. I don't know if DNG suffers from this problem or not.
02-09-2009, 04:45 PM   #12
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QuoteOriginally posted by madbrain Quote
One thing I can tell you is there no PEF codec software for 64-bit Windows. Which means on my Vista x64 machine, the only program I can use to manipulate PEFs is Pentax Photo lab. I don't know if DNG suffers from this problem or not.
Madbrain the codec is not necessary for software that understands PEF. The codec is for Windows to do things like display the PEF preview image in Explorer. So even though it is inconvenient to not have a codec for PEF in 64-bit, it certainly isn't life or death.

BTW there is no 64-bit codec for DNG either.
02-09-2009, 06:29 PM   #13
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QuoteOriginally posted by WheresWaldo Quote
Hold on there buddy!

The Pentax K10/K20 can only shoot with two gamuts sRGB or aRGB It knows nothing of CYMK or printing for that matter. Raw files whether PEF or DNG do not know about any colorspace except for the preview image which defaults to sRGB if not specified.

PEF is not a colorspace at all and it is just another linear encoding method for storing the data directly from the sensor. It doesn't print or display any different than DNG.

PEF is compressed in camera using a lossless JPEG compression algorithm. The key word here is lossless! That means it can be uncompressed into the original data without any lost data. DNG in camera is not compressed and hence has the exact same data as the uncompressed PEF. DNG files can be compressed using the same JPEG lossless compression as PEF, Pentax chose for whatever reason to not do that in camera.

The differences you claim have nothing to do with whether or not the picture was stored in PEF or DNG, but rather what colorspace was applied during processing of the raw files and how they were processed.

Let's not misinform people about what PEF or DNG is or isn't.
The two gamuts are different. The sensor always collect the same data, but the way the data is saved is different, with the lager gamut belonging to DNG. When it comes to printing, it has to be transformed to CMYK, it doesn't make any difference if it is on a computer printer or a printing press, it has to be transformed, and that happens in the computer with the software you use for printing. If you read your last paragraph, your answer is in it. The processing and storage of the data is different.
02-09-2009, 08:20 PM   #14
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QuoteOriginally posted by flyer Quote
The two gamuts are different. The sensor always collect the same data, but the way the data is saved is different, with the lager gamut belonging to DNG.
Neither DNG or PEF has a colour gamut associated with them. JPEG files do. But the control for colour space on your camera has no effect on raw files.

There is no difference in image quality when shooting DNG or PEF. The choice is provided merely as a convenience, depending on the software you prefer to use.

The real difference between one raw image and another comes from the software used to convert the raw images to raster images. Difference versions of Adobe Camera Raw can have marked effects on the resulting raster images.

And WheresWaldo is quite correct: Any compression in raw files is lossless, and does not affect image quality at all.
02-09-2009, 09:08 PM   #15
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QuoteOriginally posted by Jim Royal Quote
Neither DNG or PEF has a colour gamut associated with them. JPEG files do. But the control for colour space on your camera has no effect on raw files.

There is no difference in image quality when shooting DNG or PEF. The choice is provided merely as a convenience, depending on the software you prefer to use.

The real difference between one raw image and another comes from the software used to convert the raw images to raster images. Difference versions of Adobe Camera Raw can have marked effects on the resulting raster images.

And WheresWaldo is quite correct: Any compression in raw files is lossless, and does not affect image quality at all.
Thanks, Jim. It is obvious that flyer just doesn't get it. Whether the raw data is saved as PEF or DNG makes absolutely zero difference. There is no gamut associated with RAW data. If he doesn't want to believe us then he should just download the DNG spec from Adobe and see for himself. So, what that really means is that if you take a PEF and while working with the file you apply CYMK you will have exactly the same output if you did that with DNG.

Flyer, you are correct I answered it, you simply didn't understand the question! Look at it this way, no printer in the world, that includes personal printers, Photolab printers or offset printers can print a raw file directly. This also applies to monitors, no monitor can display RAW data directly without being "processed." They simply do not know what to do with them. All RAW files have to be processed. During that "processing" you apply a working colorspace, anything from aRGB to Working CYMK. You either print or display directly from the application, in which case it converts to a format the printer understands on the fly (usually TIFF) or that the video driver understands or you save it as such for use in a page layout application. Once there it is no longer a RAW file.

Now the source data, picture it this way, I have a file that has any combination of 26 letters. In one case I store them all in shorthand, if there are 5 a's in a row I store it as 5a, bbb becomes 3b, when I expand them nothing is lost, it is the exact data. Now I take the same data except I substitute z for every a, y for every b, etc. When I process the file I reverse the substitutions. That is a simplified way of explaining the difference between DNG and PEF. The data is still the same, there is no wider gamut nor is there a difference in the actual numbers. Like Jim and I both told you, the difference is what YOU do with the data afterward, how YOU process the data, what YOU use to work on the file.

Of course different gamuts have the ability to display or print different amounts of color, within the limits of the sensor, but the RAW data doesn't know anything about what gamut YOU will apply, nor does it care. The sensor will record what the sensor records, period!

So please reread what you wrote and realize that practically all of it was incorrect and therefore misleading.

If the OP wants to shoot all their RAW shots in PEF or chooses DNG, he/she can rest assured that all the data is there for them to use any way they see fit. No worrying if one will print or display different than any other, it does not work that way.

On a side note. I use Adobe LR and I would rather work with DNG than PEF, but I shoot only PEF. Reason is the lossless compression. I can get twice as many, or more, images on a card during a shoot using PEF. During downloading from the card I convert them automagically to DNG. Hard drive space is cheap, but that doesn't really matter either as LR will convert and compress it's DNG files. The best of one world!

Last edited by WheresWaldo; 02-09-2009 at 09:14 PM.
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