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 Post subject: PEF or DNG
PostPosted: Wed Jan 30, 2008 9:54 pm 
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Hello

Is anyone able to advise why the file sizes between pef and dng are 4 to 5mb on average?

I am trying to find out and suspect that it is either the differences in the way the format is recorded/written.

Whilst the K10D has a 22A/D converter can enyone advise what bit depth the raw file is saved on the card as?

It has crossed my mind that maybe the dng format uses a higher bit depth but this is a suspicion with no evidence as yet to back this up. 8)

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 Post subject:
PostPosted: Wed Feb 06, 2008 2:25 am 
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That's a good question, but one I don't have the answers to off-hand. I'll put a question into Pentax, but in the meantime, can any K10D owners comment?

I'm not surprised by a differecne in file size though as they will probably apply different levels of lossless compression.


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 Post subject:
PostPosted: Wed Feb 06, 2008 6:42 pm 
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Thank you Gordon for taking the time to post a reply and to search for an answer.

I'm glad you worked out that my question was missing the word 'different' - sorry for my error.

In addition to my original question I am a little bit confused with regard to bit depth in that once opened in adobe camera raw, Canon/Nikon raw files have been referred to as being up sampled from 12bit (or more recently 14 bit) to 16 bit so I wondered if this automatically means that the pef/dng are down sampled from 22 bit to 16 bit or has something else happened prior to the file being written to the card and then transferred to computer.

I suppose the crux of the matter is which is best pef or dng - pef's of course take up less room but do dng's hold any more (or less) information.

I look forward to the answers (if any) are offered by Pentax and other users.

:lol:

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 Post subject:
PostPosted: Wed Feb 06, 2008 6:51 pm 
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Bonsoir Stuey,

Weather permitting, I'll try next week-end to shoot the same picture in JPEG, PNG and PEF.

Obviously, due to file size, I can't post full sized pictures, but I could try and get the tech specs and a crop from the same area for each file format.

Stay tuned :)

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 Post subject:
PostPosted: Sun Feb 10, 2008 1:14 pm 
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Bonjour Stuey,

Here are my tests : screenshots of the 600x600 crops for all pictures. Both series of pictures were shot in JPEG+ at 1/250 f6.7 ISO100 50mm

JPEG vs DNG

JPEG 2,4 MB (ZIP = 2,4 MB)
DNG 16,2 MB (ZIP = 4,3 MB)

Image

JPEG vs PEF

JPEG 2,5 MB (ZIP = 2,5 MB)
PEF 10,5 MB (ZIP = 10,3 MB)

Image


At first look, the PNG and the PEF pictures look better than their JPEG counterparts, but not so much. Maybe a wider dynamic range, with darker blacks and lighter whites. An interesting point is the ZIP shrinkage of the PEF and DNG files. It seems that the PEF has much more information or much less redundant information.

With the tools provided with Mac OS X, I had some difficulties dealing with the PEF and DNG conversion into JPEG.

Personnally, I use the RAW format to check the colour rendition in my K10D review, especially with the red affair and the red affair continues :)

I hope that helps :!:

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reivilophotography.weebly.com


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 Post subject:
PostPosted: Sun Feb 10, 2008 9:49 pm 
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Noswaith dda (good evening) rei_vilo,

Thank your for you reply with the attached examples/photo's.

In your shots the pef appears better than the dng and the jpeg's appear noticeably sharper than the others. Could this be the level of sharpening you have applied to the raw conversions or maybe the compression applied by the zip process?

I have taken some landscape shots to highlight the difference in colours between the pef, dng and jpg's. I took some shots and then converted the pef/dng's in pse 5 using the default settings to keep things even (I have increased the settings in camera for the jpeg to sharpbess +2 and contrast +2 which is how I leave it permanently).

There are noticeable colour differences between the three and I am curious to know if one of the raw formats holds more information than the other as this could mean more flexibility in post processing.

Unfortunately I have not been able to work out how to upload my photo's to the forum, perhaps you could advise me on this one?

Hopefully I will be able to show some examples soon. :D

Cheers


Stu :roll:

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 Post subject:
PostPosted: Sun Feb 10, 2008 10:01 pm 
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Stuey wrote:
...Unfortunately I have not been able to work out how to upload my photo's to the forum, perhaps you could advise me on this one?...

Thomas wrote a handy guide which applies to all the forums and which you can read here. Hope that helps. 8)

Bob.

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 Post subject:
PostPosted: Mon Feb 11, 2008 9:49 am 
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Bonjour,

I tried to upload the pictures to Picasa : only JPEG and DNG are accepted, unfortunately PEF is refused :( .

Quote:
In your shots the pef appears better than the dng and the jpeg's appear noticeably sharper than the others. Could this be the level of sharpening you have applied to the raw conversions or maybe the compression applied by the zip process?

Both examples I provided are screen-shots of the JPEG and RAW pictures displayed on my iMac with Preview (Aperçu in French :) ) I didn't play with the Pentax Laboratory to post-process the RAW files.

Generally speaking, I use RAW files (or JPEG+) when the picture may sound difficult (red colours, landscapes, high contrast) and may need post-processing with Pentax Laboratory or iPhoto.

It helped me learning how much I could trust the K10D in-process to JPEG file. This is part of the K10D learning curve :wink:

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--- rei_vilo
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reivilophotography.weebly.com


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 Post subject:
PostPosted: Mon Feb 11, 2008 8:30 pm 
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Location: Wales
Hello All (again)

Unfortunately, whilst I have a flickr account set up I am waitng for a few hours spare to enable me to learn how to and then choose some photo's and inflict them upon the viewers of flickr 8) - unfortunately doing this is some way behind my other priorities (being a dad, keeping the girlfriend happy, taking photo's, working full time etc) if I had my way I would have loads of time for this but as it is I have to try to squeeze it in around the rest. :shock:

I will try my best to allocate some time.

As you can see re-vilo is easily putting me to shame, and especially concidering I asked the question I will do my very best to contribute to helping to find the answer.

Thanks again to those who are helping.


Cheers

Stu

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 Post subject:
PostPosted: Mon Feb 11, 2008 9:55 pm 
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Bonsoir Stuey,

In order to improve the JPEG pictures, you could use the extended bracketing on the K10D to test different values for white balance, saturation, sharpness and contrast. This isn't so well explained in the user manual.

Just select Menu > Capture parameters > Extended bracketing (page 2/2 line 3) > White balance / Saturation / Sharpness / Contrast.

Actually, the K10D takes one picture and process it 3 times, one for -1, one for 0, one for +1. In short, press one and get 3 pictures :!: The ±1 could be set to ±3 or even ±5 by selecting Menu > Capture parameters > Extended bracketing (page 2/2 line 3) > Bracket increment.

Obvioulsy, you can't play but with only one parameter. But this could greatly help you selecting the values for Menu > Saturation, Menu > Sharpness and Menu > Contrast.

However, extended bracketing could be combined with bracketing (the hard button on top of menu), then taking 3 shots and delivering 9 pictures :!:

For example, saturation +1 is usually recommended for landscapes.

In my case, the iPhoto standard post-processing has seemed enough for me. In difficult cases, I rather prefer to press the button RAW on and get a JPEG file + a RAW file I could process after with Pentax Laboratory or iPhoto.

Have fun :)

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Pentax K-5 + BG4 + DA* 16-50 + DA* 50-135 + DA* 60-250 + AF-540FGZ
reivilophotography.weebly.com


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 Post subject:
PostPosted: Fri Mar 07, 2008 9:53 am 
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Bonjour Stuey,

There's a very interesting comparison between PNG and PEF at one Pentax site.

Go to :arrow: Izumi Taniguchi Digiichi Photo Technique Workshop.
On the top-right drop-down list, select Seminar vol. 24 and then scroll down to Column n° 20


Quote:
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.

(C)2008 PENTAX Corporation All Rights Reserved.


There is much, much more to discover on this excellent site :)

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--- rei_vilo
Pentax K-5 + BG4 + DA* 16-50 + DA* 50-135 + DA* 60-250 + AF-540FGZ
reivilophotography.weebly.com


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 Post subject: PEF or DNG
PostPosted: Mon Mar 10, 2008 9:24 pm 
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Joined: Fri Jan 18, 2008 7:27 pm
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Location: Wales
Good Evening

Thank you for the response rei_vilo and sorry for the delayed response but I have spent a bit of time on that link :D

I have switched back to PEF for the timebeing having tried DNG and will continue to test the two.

It's just a shame that as yet we are unable to find out what 'bit depth' the raw files are when they are stored on the card and if there is a difference does it matter if I use an adobe programme to post process as it works in 16 bit anyway.

Even though my question may be of little relevance I am still interested to know - I suppose that's one of the problems of having two raw formats to chose from (I am not complaining about this).


Cheers


Stu

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