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06-05-2016, 04:09 PM   #1
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RAW file size

I was wondering why the K-1 raw files are about 45 MB when the Nikon D800s files are 75MB...

06-05-2016, 04:21 PM   #2
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QuoteOriginally posted by Tjompen1968 Quote
I was wondering why the K-1 raw files are about 45 MB when the Nikon D800s files are 75MB...
The K-1 uses lossless compression. (Both PEF and DNG).

Otherwise, it would use two bytes for each pixel, hence about 73 MB or so.
06-05-2016, 04:36 PM   #3
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Doesn't Nikon offer two types of raw, one is full and lossless, the other is compressed and has smaller file size? I don't use Nikon, so I don't know, but I think there is possible to get Nef files of various sizes from the same camera.

Pentax' compression is decent, though. You don't lose any data. As far a I know, both K-1 and D800 have same MP and same bit depth. The other thing is that once compression is involved, you get really different file sizes depending on the subject. It depends mostly on whether the frame is busy, with lots of edges and colours, with lots of noise. Then the file will be larger.
06-05-2016, 04:37 PM   #4
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QuoteOriginally posted by Na Horuk Quote
Doesn't Nikon offer two types of raw, one is full and lossless, the other is compressed and has smaller file size? I don't use Nikon, so I don't know, but I think there is possible to get Nef files of various sizes from the same camera.

Pentax' compression is decent, though. You don't lose any data. As far a I know, both K-1 and D800 have same MP and same bit depth. The other thing is that once compression is involved, you get really different file sizes depending on the subject. It depends mostly on whether the frame is busy, with lots of edges and colours, with lots of noise. Then the file will be larger.
Their small raw files are 12 bit and they are compressed, but they're not available on all models.

Lossless compression saves a lot of disk space, but it also costs extra processing time while saving the file. Perhaps that's also part of the reason why the K-1 takes more time to save its files.


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06-05-2016, 05:16 PM   #5
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QuoteOriginally posted by Na Horuk Quote
Doesn't Nikon offer two types of raw, one is full and lossless, the other is compressed and has smaller file size? I don't use Nikon, so I don't know, but I think there is possible to get Nef files of various sizes from the same camera.

Pentax' compression is decent, though. You don't lose any data. As far a I know, both K-1 and D800 have same MP and same bit depth. The other thing is that once compression is involved, you get really different file sizes depending on the subject. It depends mostly on whether the frame is busy, with lots of edges and colours, with lots of noise. Then the file will be larger.
In this case the same image and settings and I find that most my pef:s are somewhere around the 45 MB size.
06-05-2016, 05:54 PM   #6
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Raw file can greatly vary in size due to the complexity of the information stored.
06-05-2016, 10:31 PM   #7
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QuoteOriginally posted by Tjompen1968 Quote
RAW file size I was wondering why the K-1 raw files are about 45 MB when the Nikon D800s files are 75MB...
You ask accurate questions. Be wise and don't dig a hole this direction :-)
06-05-2016, 11:29 PM   #8
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The K-1 is well abled to produce RAW files in the 70+ MB range. Just shoot something with lots of detail and add some noise by shooting in low-light conditions with severe high-ISO settings.

06-06-2016, 12:56 AM   #9
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QuoteOriginally posted by Tjompen1968 Quote
In this case the same image and settings and I find that most my pef:s are somewhere around the 45 MB size.
What if you export raw files from both cameras into uncompressed tiff? Do they become more similar in size?

I think if there were 30MB of data "missing" in the K-1, that would have a noticeable impact on image quality. Pretty much any good reviewer would have to notice such a big thing. So its probably just different compression algorithms and different subject matter that makes up for it.
I know with my 16MP cameras there are quite big variations in file size. At lowest ISO, with not much detail, they are small. At a high ISO, of busy things like twigs scattered along a forest floor, the size increases a lot.
06-06-2016, 02:59 AM   #10
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QuoteOriginally posted by Na Horuk Quote
I think if there were 30MB of data "missing" in the K-1, that would have a noticeable impact on image quality.
Depends, since there are 2 greens, 1 red and 1 blue to make one RGB pixel, a loss of one green information would have only a few percent difference in spacial coding after interpolation. If the K1 SD card write is limited to about 30MB/s (compared to double that speed in other FF DSLRs), dropping 1 bit of green (decimating 14bits words into one 14bits word) is actually a serious advantage. You'd only lose a few percent of resolution but gain a lot on data storage, burst rate, and how many raws can be buffered from a burst, while still having 14 bits depth on the green. If Ricoh reused the same tech plateform from the K3, then all this makes sense. Otherwise if the raws were 72Mbytes large, it would clog the raw 4.4FPS burst mode that would become noticeably less usable.

Personnally, since I'm content with 24Mpixels files, the 45Mbytes of the 36Mpixels raws is already too much for me. What I not so happy about is actually that we don't have an option for better JPEG quality, for example when using the 22Mpixels mode.

Last edited by biz-engineer; 06-06-2016 at 03:05 AM.
06-06-2016, 04:43 AM   #11
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QuoteOriginally posted by biz-engineer Quote
Depends, since there are 2 greens, 1 red and 1 blue to make one RGB pixel, a loss of one green information would have only a few percent difference in spacial coding after interpolation. If the K1 SD card write is limited to about 30MB/s (compared to double that speed in other FF DSLRs), dropping 1 bit of green (decimating 14bits words into one 14bits word) is actually a serious advantage. You'd only lose a few percent of resolution but gain a lot on data storage, burst rate, and how many raws can be buffered from a burst, while still having 14 bits depth on the green. If Ricoh reused the same tech plateform from the K3, then all this makes sense. Otherwise if the raws were 72Mbytes large, it would clog the raw 4.4FPS burst mode that would become noticeably less usable.
When shooting DNG, each sensor pixel becomes one 16-bit word. No words are discarded. Hence about 73 MB before compression for the K-1.

This is then compressed using "lossless JPEG" compression. Normally this results in DNGs between about 40 MB and (less than) 60 MB. But when I shot at maximum ISO (hence lots of noise) the DNGs were between about 60 and 70 MB.
06-06-2016, 05:20 AM   #12
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QuoteOriginally posted by Barry Pearson Quote
This is then compressed using "lossless JPEG" compression. Normally this results in DNGs between about 40 MB and (less than) 60 MB. But when I shot at maximum ISO (hence lots of noise) the DNGs were between about 60 and 70 MB.
Indeed, your experiment give some hint that raws aren't raws per say, it the file size isn't fixed. Interesting. Does it means the DNG could be read as a JPEG is the files header was modified to look like a JPEG?
06-06-2016, 05:23 AM   #13
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QuoteOriginally posted by biz-engineer Quote
ndeed, your experiment give some hint that raws aren't raws per say, it the file size isn't fixed.
You have a rather crazy view of RAW's. Why do you presume RAW's should be an immutable size?

PS: there is a reason the standard testing for RAW file size is at ISO 100.
06-06-2016, 07:36 AM   #14
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QuoteOriginally posted by rawr Quote
Why do you presume RAW's should be an immutable size?
By definition if the raw file is the data pattern coming from the sensor without complex machine processing such as fft (jpeg), the content of this file should simply be a dump of 14 bits per pixels, , even if the data of each RGB color is 0000_0000_0000_0000 (total black), inevitably of fixed size regarding data because one word of value 0000_0000_0000_0000 occupy two bytes. If not, then the raw is processed and can be any recipe chosen by the manufacturer to meet their goal.
06-06-2016, 07:37 AM   #15
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QuoteOriginally posted by biz-engineer Quote
Indeed, your experiment give some hint that raws aren't raws per say, it the file size isn't fixed. Interesting. Does it means the DNG could be read as a JPEG is the files header was modified to look like a JPEG?
It is still raw data, it is only further compressed. Many years ago, cameras didnt have compression, so the files were always exactly the same size, regardless of subject. In modern Pentax DSLRs, the data gets compressed. As you know, there are two types of compression: lossy, and lossless. This does not mean the original data gets changed, it is not the same as taking raw image data and turning it into a jpeg photo.
I think modern Tiff and Psd files also allow compression. This doesnt mean the Dng contain wrong data, just that the data gets compressed for recording. It just means that the Dng container allows some modern technologies like compressing data to reduce the space it takes.

That said, I think tests have shown that pretty much all modern DSLRs have some level of raw-cooking (regardless of compression, as this happens before compression). The question is just how much. I think Pentax has a really low amount of this, compared to, for example Sony. I havent seen this type of analysis done on the K-1 yet
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