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01-09-2011, 03:13 AM   #1
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For the file size conscious

I have only just managed to test this out, my workflow (with the K200) has always been to shoot in RAW (PEF) and convert afterwards on the computer to dng using DNG converter, for no reason other than there are some savings in file sizes (probably about 20-30% from what I remember). I just did a test, very small sample size admittedly (two pictures), but from that, it seems that some file size savings can still be gained from shooting in PEF and converting to DNG afterwards. I shot two identical pictures (practically speaking), DNG = 21.2MB, PEF = 20.7MB, converted DNG = 17.5MB, and another test shot, DNG = 23.3MB, PEF = 23.2MB, converted DNG = 18.5MB. I'm not particularly interested in what exactly is the difference between the files, just the actual file sizes, so if you're skimp for hard drive space, there's something you can do to squeeze a bit more out of your hard drive.

dave

01-09-2011, 03:48 AM   #2
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Mate, you're getting some big PEF file sizes there...
My K10D PEFs were around the 12MB figure, my K20D PEFs around the 14-15MB range.
I shoot my K-x in DNG format since I don't have CS4 to read those PEFs and I still only get to 14-15MB. On the rare occasion would a PEF file hit the 18MB mark.

Hence my preferences are for PEF - they seem to be smaller than my DNGs.
01-09-2011, 06:14 AM   #3
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I'm gonna buy 2 Tb harddiscs and not gonna put time in making the DNG's from the K-5 smaller. I shot yesterday a lot of photo's with hi iso among them and average is 22,5 Mb.
01-09-2011, 07:17 AM   #4
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QuoteOriginally posted by Ash Quote
Mate, you're getting some big PEF file sizes there....
I think the OP's talking about the K-5, in which case the file sizes are about right.

I.e. he had a workflow with the K200D, which was to shoot in PEF then convert to DNG. Now that he's gotten a K-5, he's done a quick test of 2 photos, and the same workflow of shooting in PEF then converting to DNG to save file size still works.

01-09-2011, 02:57 PM   #5
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Oops, haha, didn't mention I was using the K-5, probably thought it would be implied when I posted this.
01-09-2011, 03:17 PM   #6
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I was misled by the first part...

QuoteOriginally posted by dtra Quote
I have only just managed to test this out, my workflow (with the K200)
Anyway, carry on... 20MB for PEFs isn't bad at all for 16Mp images. Getting further compression to DNG is all kudos to you.
01-09-2011, 05:45 PM   #7
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I just checked 52 pictures and they where 8.2 - 9.7 per file. My K5
01-09-2011, 05:53 PM   #8
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There used to be a size benefit in converting to DNG later on. That was because Pentax didn't use lossless compression with DNG. However, that was fixed with the K-7 and size-wise, PEF vs. DNG shouldn't be different anymore and what you see confirms it.

The savings in converting to DNG may be from a higher compressed embedded JPG. That should be obtainable from DNG alone by remaking or deleting the embedded JPGs. photome shows the size of the raw and full size JPG and thumbnail JPG parts.

BTW, the size of a DNG/PEF depends on compressibility which is about zero at higher ISO levels (a noise-only signal is incompressible which is a mathematically hard fact).

01-13-2011, 06:35 AM   #9
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FWIW, a converted DNG doesn't contain all the data of the original PEF, at least for the K20D. The masked sensor pixel data is stored in the PEF but stripped out in the DNG conversion process. Should hardly be noticeable in terms of size, I'm just mentioning this for those who believe that a converted DNG contains exactly the same data as the original PEF.

I don't think there is any other data loss, but I don't really know. If you believe the Bibble people there is hardly anything worse than a converted DNG file (which is why they don't support it).

Of course, for many the lost data isn't a real loss.
01-13-2011, 09:20 PM   #10
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QuoteOriginally posted by dtra Quote
Oops, haha, didn't mention I was using the K-5, probably thought it would be implied when I posted this.
Well it is the K-5 forum
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