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03-21-2008, 03:42 AM   #31
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hm very interesting I was going to be using DNG but I've changed my mind mainly because of file size. as a note I would like to point out that I took two identical images on my K10D one in DNG and one in PEF the PEF was 11 MB the DNG 16.2 MB then I compressed the DNG in rar and it came out at 11.6 MB so I would say PEF has some very specific zip (lossless) compression.

I still havn't figured out what the colour space selection is all about ? I mean raw is raw its the camera sensors data I can only assume that using adobe space just means you don't have to switch to it later in post processing.

03-21-2008, 04:33 AM   #32
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QuoteOriginally posted by Rusty Quote
Thanks for that Richard.

Do you have a link to the original diagrams?

Cheers,
Rusty
They are from some Powerpoint presentations I was given.

If you want to see them in more detail just click on the image to enlarge them.
03-21-2008, 04:49 AM   #33
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QuoteOriginally posted by 123K10D Quote
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.
This guy calling it with this information calls himself Yahzid (sp?) from Pentax France. Maybe Ben could track him down to get to the bottom of this affirmation ?

Yahzid clearly states that he was informed (from Pentax Japan) that using DNG entails a 10% "loss" vs. using PEF (he does not mention 10% of what).

FWIW, I trust GordonBGood's technical analysis more than an unbacked claim on a web radio program
03-21-2008, 04:56 AM   #34
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QuoteOriginally posted by Jodokast96 Quote
Not true at all. I shoot DNG and use Photo Lab all of the time with them.
The original "camera produced" DNG's are not compressed, that's why you can use Photo Lab with them. Photo Lab doesn't read DNG files compressed by the Adobe desktop converter, or compressed via ACR.

If you convert a PEF to DNG within Pentax Photo Browser, it becomes an uncompressed 16 bit DNG which are very large, as the remaining 4 bits of data are not stripped, as they are in the camera. This is very similar to the original istD PEF's which also retained the unused 4 bits and were very large compared to the DS PEF's which had the 4 unused bits removed. The K10D and K20D went a stage further and losslessly compressed the 12bit PEF files "in-camera".

03-21-2008, 05:34 AM   #35
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QuoteOriginally posted by baw Quote
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.
sorry, open format/spec. it was pretty late when i wrote that

how can they possibly not "publish all specs" and yet my k10d has dng as a format option? from a programmers pov, that's one hell of a contradiction.
03-21-2008, 05:48 AM   #36
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maybe if you guys thought of it like this ... dng is the same concept as pdf (universal), and applied to camera output. the contents of the container are the same; the container is universal. pentax's container (pef) is not universal. you will not find a competitor's camera body/software supporting pef, unlike dng.
03-21-2008, 05:50 AM   #37
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I posted this on DPReview lately:

From the horse's mouth (Pentax Japan): when shooting in DNG, the K10D stores about 10% less information than in PEF.

I have no information about what is lost though, it would be interesting to know...
You can listen to the 7 mns interview (in French) here:

http://www.declencheur.com/clic/medias/2008/decl-2008-02-22.mp3
03-21-2008, 06:00 AM   #38
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QuoteOriginally posted by luxart Quote
I posted this on DPReview lately:

From the horse's mouth (Pentax Japan): when shooting in DNG, the K10D stores about 10% less information than in PEF.

I have no information about what is lost though, it would be interesting to know...
You can listen to the 7 mns interview (in French) here:

http://www.declencheur.com/clic/medias/2008/decl-2008-02-22.mp3
that's literally impossible. maybe the translation is wrong, or the guy simply used the wrong phrase in relation to the file size. there is a difference in compression between the 2 formats on the pentax bodies.

03-21-2008, 06:09 AM   #39
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QuoteOriginally posted by simons-photography Quote
I still havn't figured out what the colour space selection is all about ? I mean raw is raw its the camera sensors data I can only assume that using adobe space just means you don't have to switch to it later in post processing.
the color space option is for shooting jpegs. when you process the raw you choose the color space of the output format.
03-21-2008, 06:29 AM   #40
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QuoteOriginally posted by attack11 Quote
how can they possibly not "publish all specs" and yet my k10d has dng as a format option? from a programmers pov, that's one hell of a contradiction.
As far as my understanding goes, they haven't published the way the "soft" edits are stored in the DNG file, effectively keeping the format closed.
03-21-2008, 06:35 AM   #41
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QuoteOriginally posted by attack11 Quote
maybe if you guys thought of it like this ... dng is the same concept as pdf (universal), and applied to camera output. the contents of the container are the same; the container is universal. pentax's container (pef) is not universal. you will not find a competitor's camera body/software supporting pef, unlike dng.
With PDF Adobe has prevented Microsoft from offering PDF as an output option in Office.
Same might happen with DNG.
Also see the way they silently changed the XMP specs.
You're effectively locked into using Adobe software this way.
03-21-2008, 06:42 AM   #42
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considering ms is the only company that's been blocked from including native support; we have no idea what went down behind closed doors for that course of action to be implimented.

you're locked into companies format's regardless of what you choose. i'm personally not switching to dng until it's completely supported by all, at that point pef can simply disappear.
03-21-2008, 07:23 AM   #43
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In terms of image quality, RAW has a definite advantage over other recording formats. This does not mean, however, that you should select RAW for every subject and in every situation. RAW naturally has strengths and weaknesses; the best way to optimize the benefits of digital photography is to fully understand the individual characteristics of all recording formats, so you will know when to choose RAW, and when to switch to JPEG.




Since RAW data is undeveloped, it must always go through a development process to create an image. Normally we think that digital cameras require no development process, but the truth is that JPEG data is instantly developed within the camera to produce a photographic image. Because it’s a split-second process, it seems that no development process is needed, compared to the time-consuming development process required for film cameras.

One definite disadvantage of the RAW format is the time and trouble required by the data-development process necessary to create the image. Since this development is usually handled on a personal computer, this also means that you must set up the system and learn the essential processing skills.

Some may think that this process is actually an advantage of RAW. You can spend more time and be more meticulous about image development because you personally develop the RAW data. Imagine that you are planning to retouch an image after shooting. With a JPEG-format image, retouching is in fact the second development, because you are actually redeveloping an image previously developed by the camera. If you want to retouch a captured image, you should definitely choose RAW, rather than doubling the development process and causing a deterioration in image quality with JPEG. We studied this interrelation between the image development process and image-quality deterioration last month, so you should be familiar with this by now.




Colors in a photograph are reproduced during the development process. That means that undeveloped RAW data is not a photograph, because it has no colors in it. You add colors to RAW-format images only by developing them.

One big advantage in RAW-format shooting is that you can leave the white-balance setting at auto all the time. When you are uncertain about a proper white-balance setting, or when you come across a subject or scene with a complex color combination, you can always use RAW, then develop the image later the way you want it.

This method can be very risky with JPEG, particularly in terms of image quality, because you are changing the original colors of an already-developed image. Remember this as one of RAW’s important advantages.





As I explained last month, one of the biggest differences between the irreversible-compression JPEG format and the reversible-compression RAW format is the file space required for each image.

Let’s look at RAW’s usefulness in more concrete terms. By the way, the figures used here are the average of the manufacturer-provided specifications: the actual number of recordable images may differ depending on the type of image you take.

When you select an image size of 10 megapixels and use a 1GB recording media in the K10D, you should be able to capture approximately 202 images at Best (or lowest-compression) image quality of the JPEG format. If you switch the recording format to RAW under the same conditions, you can only take 59 images. In other words, RAW demands 3.5 times more file space than JPEG.

This tells you that, in terms of the number of recordable images, it’s impractical to choose RAW for all images in day-to-day shooting.





The following setbacks are very much related to the issues regarding RAW’s large file-space demands, as described in Point 3. RAW-format shooting means delayed camera response and slower data-processing/transmission speeds, simply because RAW files are bigger. This problem becomes more evident in consecutive shooting.

Based on the average of the manufacturer-provided specifications, you should be able to keep shooting images until the recording media runs out of storage space — a process known as “stream shooting” — when you set the K10D to the 10-megapixel image size and Best (lowest-compression) image quality of the JPEG format.

In RAW-format stream shooting, you should be able to capture approximately nine images in succession. This suggests that RAW is not suitable for consecutive-shooting applications involving moving subjects, such as fashion shows and sports events.

Because of its large data volume, RAW also requires a high-capacity personal computer to improve the speed and efficiency of post-shooting processes, including data transmission and photo retouching. In addition, greater filing space is required to store the final image data. Considering all these factors, you must be fairly well prepared to comfortably use RAW.




When you want to take RAW-format images all the time, set the camera’s recording format to either RAW or RAW+ (simultaneous recording of RAW and JPEG images).

The K10D also offers the convenient RAW button, which allows you to instantly switch the recording format to RAW+ during JPEG-format shooting. This means that you can use JPEG in ordinary shooting, then switch to RAW via simple pushbutton operation whenever you need it.

Via a custom function, you can assign one of two functions to this RAW button: either reset to the original recording format after a single exposure, or maintain the RAW+ setting until the playback button is pushed.

With the K10D, you can also select the DNG (Digital Negative) file format, in addition to the conventional PEF (PENTAX RAW) format.

DNG is a new, multipurpose RAW-data file format advocated by Adobe System, who is widely known as the manufacturer of the popular Photoshop retouching software. This publicly available archival format makes it possible to develop RAW-data files using any compatible RAW-data development software.


How to select RAW as the standard recording format
The following procedure should be followed when selecting RAW as the camera’s standard recording format. I recommend, however, that you choose JPEG as the standard format and use the RAW button when you wish to preserve RAW-format images.

Step 1: Step 2:

After pressing the MENU button to recall the rec. mode menu on the LCD monitor, use the up/down keys of the four-way controller to select the recording format listing. After pressing the right key of the four-way controller to display the set of recording formats, use the up/down keys of the four-way controller to select the desired recording format. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.


How to select a RAW-data file format (PEF or DNG)

Step 1: Step 2:

After pressing the MENU button to recall the rec. mode menu on the LCD monitor, use the up/down keys of the four-way controller to select the RAW-data file format listing. After pressing the right key of the four-way controller to display the two RAW-data file formats, use the up/down keys of the four-way controller to select the preferred format. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.


How to use the RAW button

Step 1: Step 2:

During JPEG-format shooting, press the RAW button to switch the recording mode to RAW+. This lets you simultaneously record both JPEG- and RAW-format images with the next shutter release. RAW+ is indicated on the LCD panel on the camera’s upper panel to confirm your recording-format switching. At the camera’s default setting, the standard recording format (JPEG) is restored after a single exposure.


How to assign a RAW button function
You can choose a desired RAW button function: either reset to the standard recording format after a single exposure, or to maintain the RAW+ format indefinitely until the playback button is pushed.

Step 1: Step 2:

After pressing the MENU button to recall the menu on the LCD monitor, use the right/left keys of the four-way controller to display the custom setting menu. Then, use the up/down keys or the front electronic dial to move to a custom setting page with a RAW-button function listing. Use the up/down keys of the four-way controller to highlight the one-touch RAW+ listing on the selected page.

Step 3:
After pressing the right key of the four-way controller to display two one-touch RAW+ functions, use the up/down keys of the four-way controller to select a preferred one between one time and continuous. Then press the OK button to confirm your selection. Finally, press the MENU button again to complete the procedure.



Over the last two months, we have studied both the benefits and disadvantages of the RAW recording format. If you have clear understanding of these, you know the right times to choose RAW:

When your priority is image quality;
When you want to retouch recorded images;
When you are uncertain about the proper white-balance setting;
Use JPEG for ordinary shooting, then switch to RAW using the RAW button when needed;
Choose RAW for subjects and scenes that require no consecutive shooting.




RAW-format special seminar: Part 3
Development process of RAW-format images


Now that you have learned the benefits of the RAW format, when to take advantage of this unique format and how to set the different RAW functions, it’s time to actually develop RAW-format images.






Which RAW suits you better — PEF or DNG?


I have mentioned two different RAW-data file formats: the original format (PEF, for PENTAX) and the Adobe System-advocated DNG format. It’s very understandable that DNG has attracted tremendous attention since its introduction, because it was developed and advocated by Adobe System, the developer and marketer of Photoshop — the de facto standard in the world of photo retouching software.

DNG provides an option to users of digital SLR cameras like the K10D, but I’m frequently asked about which format to choose. I usually answer that they should choose PEF — at least for the time being.

As a RAW-data file format, PEF files are processed with a certain degree of reversible compression, while DNG files are uncompressed. Because of this, I’m not convinced of the practical usefulness of DNG files at this point.

Secondly, most computer operating systems and software applications are designed to accommodate the original RAW-data file formats of major camera manufacturers. So I cannot come up with any particular reason to switch to a public, multipurpose format like DNG. Honestly speaking, even though a few years have passed since the introduction of DNG, it is not as popular as was originally expected, perhaps because of the issues I have mentioned.

Finally, in terms of visual expression, RAW-format images are not processed by the camera’s imaging engine — the key factor to reproducing the individual touches and renditions of each camera manufacturer. This means that RAW-format images lack brand originality. I suspect that, if you choose the DNG format and process DNG-format images with multipurpose data-processing software, you can no longer make a distinction among the different camera brands.

In this case, data-development software plays a very important role. Because I’m very fond of PENTAX’s visual presentation, I always use PENTAX PHOTO Laboratory, PENTAX’s original RAW-data processing software, to process RAW-format files.

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.





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03-21-2008, 09:57 AM   #44
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QuoteOriginally posted by attack11 Quote
considering ms is the only company that's been blocked from including native support; we have no idea what went down behind closed doors for that course of action to be implimented.
I use the R:Base dbms, and they licensed PDF output from Adobe. I will bet you an orange to two apples that MS simply would not pay the license fee.
03-21-2008, 11:01 AM   #45
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QuoteOriginally posted by luxart Quote
From the horse's mouth (Pentax Japan): when shooting in DNG, the K10D stores about 10% less information than in PEF.
Probably metadata and makers notes. All photosite values must be EXACTLY the same, otherwise the format would not qualify as RAW at all.

They are probably talking about this (my guess): since DNG is a standard anything non-standard will be lost. Lets imagine that Pentax camera stores something like this in PEF metadata (this is NOT how it really works, but the idea is important here):

ISO=400
FOCAL_LENGTH=21
SHUTTER_SPEED=1/125
APERTURE=f/5.6
SR_ON=yes
MODE=TAv

IMAGE_DATA=101000101010001010100101010111110101000010101.... (for all RGGB)

Now, you convert this to DNG (or save as DNG) and you have to follow the standard and in the conversion process you may loose something (marked in red) so you may get something like this:

ISO_VALUE=400
FOCAL_LENGTH=21
SHUTTER=1/125
F_STOP=f/5.6
CAMERA_MODE=0x3F (note: present but unrecognized)
DATA_BLOCK=101000101010001010100101010111110101000010101.... (for all RGGB)

Tags may be named differently, and some maker-specific information may be modified or lost, but all binary image data MUST remain the same. I believe that is what they are talking about.

This is like ZIP vs. RAR: you compress a file and later you decompress it and get exactly the same file. ZIP and RAR store data differently, archivers processes data differently but for all practical purposes all that is irrelevant.

Last edited by Ivan Glisin; 03-21-2008 at 11:07 AM.
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