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06-02-2009, 12:40 AM   #1
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14bits vs. 12bits raw conversion

ok, so I believe this is important, isn't it?

i personally do not understand how would one experience that 14bits raw conversion is better than 12bits, which we know pentax uses.

can anyone explain that to me?

in which situations, circumstances one can notice the difference and what's that difference is?

i believe the more, the better but.. is it really important?

thanks for your answers.

and by the way, since K-m uses feature, that when used in a 2 seconds self timer, shake reduction is disabled automatically, wouldn't we expect the same on k-7?

06-02-2009, 05:02 AM   #2
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I don't think it matters.
Especially since Pentax in PPL uses 8 bit only!
06-02-2009, 06:16 AM   #3
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Actually, I think it's a big deal. The bit depth has a lot to do with potential dynamic range and how well the sensor (or the processing pipeline) can separate or "deliniate" colors. Banding/posterization is a side affect of not having enough bit depth. Oddly enough, this tends to show up more with B&W images than it does color. The real deal with high bit depth is that it gives you greater latitude when editing the image, particularly curve moves, before you start to suffer the side effects of banding/posterization.

I'm not sure about PPL being 8bit only since I don't use it but in a RAW converter such as ACR and others, you should be able to access the full bit depth of the sensor data and then convert up to 16bit/channel or down to 8bit/channel as you see fit.

I get to talk to professional commercial photographers in my line of work that use the expensive Sinar, Phase One and Leaf backs and they will tell you that capture bit depth is at least as important, maybe more important, than the actual sensor's megapixels.

In my opinion, this is one of the areas that will always keep Pentax DSLRs from being in the same rank as the true professional-level DSLRs such as the Nikon D3X, Canon 1DS MkIII and others, maybe even more so than sensor format. Until they step up to things like 14bit capture they will probably forever be relegated to advanced amateur/semi-pro status. Just my opinion....but I love my K20D!

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WyseConsul, Color Management Consulting
06-02-2009, 06:38 AM   #4
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QuoteOriginally posted by blende8 Quote
I don't think it matters.
Especially since Pentax in PPL uses 8 bit only!
Where do you get that from? It will export in 16bit TIFF so I doubt if processing is only 8bit... I actually doubt if any good RAW program uses 8bit in RAW processing.
As to the original question, the best answers are at the Nikon debates regarding it. With current sensor technology exceeding 12 bit "appears" to be somewhat a gimmick (due to the last 2 bits being mostly noise) though strongly debated....
I need more evidence it is valid.....
PRO and CON sort of:
http://www.earthboundlight.com/phototips/14-bit-raw-12-bit-part-two.html
http://photomatter.com/Reviews/NikonD300d.html
When a camera is shooting in 12 bits per color the three luminosity values contain
4096 shades of each primary color. 4096 shades of red, 4096 shades of blue, and 4096 shades of green, or 4096
x 4096 x 4096 = 4,398,046,511,104 potential colors. (that is right - over 4 trillion colors). When we raise the bit
depth to 14 bits per color - instead of 4096 colors per primary color - it goes to 16,384 shades of color per each
primary luminosity channel. This staggering number of potential colors is expressed like so - 16,384 x 16,384
x 16,384 = 281,474,976,710,656. or over 281 trillion colors.

how many colors does one need w/ small gamut printers/monitors......


Last edited by jeffkrol; 06-02-2009 at 06:47 AM.
06-02-2009, 07:02 AM   #5
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QuoteOriginally posted by jeffkrol Quote
Where do you get that from? It will export in 16bit TIFF so I doubt if processing is only 8bit...
Export an 8-bit and a 16-bit TIF and compare!
e.g. count the colors or look it up in a Hex editor.
8 bit.
06-02-2009, 07:16 AM   #6
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QuoteOriginally posted by blende8 Quote
Export an 8-bit and a 16-bit TIF and compare!
e.g. count the colors or look it up in a Hex editor.
8 bit.
I'll look into it. I'd assumed Pentax/Silkypics wouldn't be that stupid. BTW: that is still circumstantial. They may reduce to 8bit on export but there is yet no proof that the 10bit Raw's are truncated during processing, just afterwards???
Just trying to get a full picture of this.....
File sizes are extremely different but hollow bits will do this as well..........

Last edited by jeffkrol; 06-02-2009 at 09:03 AM.
06-02-2009, 10:02 AM   #7
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Original Poster
thanks

thank you all for an interesting discussion. even though i do not have anything to add to it, it's interesting to read.
06-02-2009, 10:53 AM   #8
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QuoteOriginally posted by jeffkrol Quote
They may reduce to 8bit on export but there is yet no proof that the 10bit Raw's are truncated during processing, just afterwards???
Right.
That's possible.
We have no way of knowing.

06-02-2009, 12:20 PM   #9
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For arguements sake

and nothing is ever as straightforward as it seems..........
Curiously, all the 14-bit cameras on the market (as of this writing) do not merit 14-bit recording. The noise is more than four levels in 14-bit units on all of these cameras (Nikon D3/D300, Canon 1D3/1Ds3 and 40D); the additional two bits are randomly fluctuating, since the levels are randomly fluctuating by +/- four levels or more. Twelve bits are perfectly adequate to record the image data without any loss of image quality, for any of these cameras (though the D3 comes quite close to warranting a 13th bit).

A qualification is in order here -- the Nikon D3 and D300 are both capable of recording in both 12-bit and 14-bit modes. The method of recording 14-bit files on the D300 is substantively different from that for recording 12-bit files; in particular, the frame rate slows by a factor 3-4. Reading out the sensor more slowly allows it to be read more accurately, and so there may indeed by a perceptible improvement in D300 14-bit files over D300 12-bit files (specifically, less read noise, including pattern noise). That does not, however, mean that the data need be recorded at 14-bit tonal depth -- the improvement in image quality comes from the slower readout, and because the noise is still more than four 14-bit levels, the image could still be recorded in 12-bit tonal depth and be indistinguishable from the 14-bit data it was derived from.

Noise, Dynamic Range and Bit Depth in Digital SLRs -- page 3
06-02-2009, 12:37 PM   #10
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QuoteOriginally posted by jeffkrol Quote
and nothing is ever as straightforward as it seems..........
Curiously, all the 14-bit cameras on the market (as of this writing) do not merit 14-bit recording. The noise is more than four levels in 14-bit units on all of these cameras (Nikon D3/D300, Canon 1D3/1Ds3 and 40D); the additional two bits are randomly fluctuating, since the levels are randomly fluctuating by +/- four levels or more. Twelve bits are perfectly adequate to record the image data without any loss of image quality, for any of these cameras (though the D3 comes quite close to warranting a 13th bit).

A qualification is in order here -- the Nikon D3 and D300 are both capable of recording in both 12-bit and 14-bit modes. The method of recording 14-bit files on the D300 is substantively different from that for recording 12-bit files; in particular, the frame rate slows by a factor 3-4. Reading out the sensor more slowly allows it to be read more accurately, and so there may indeed by a perceptible improvement in D300 14-bit files over D300 12-bit files (specifically, less read noise, including pattern noise). That does not, however, mean that the data need be recorded at 14-bit tonal depth -- the improvement in image quality comes from the slower readout, and because the noise is still more than four 14-bit levels, the image could still be recorded in 12-bit tonal depth and be indistinguishable from the 14-bit data it was derived from.

Noise, Dynamic Range and Bit Depth in Digital SLRs -- page 3
+1

12 bits are plenty for our current APS-C and 35mm sized sensors.
06-02-2009, 02:06 PM   #11
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Causes wonderful discussions though

QuoteOriginally posted by arpaagent Quote
+1

12 bits are plenty for our current APS-C and 35mm sized sensors.
Auto ISO and number of RAW bits needed at higher ISO values - Open Photography Forums
Lots of nice features over my 30D (sensor cleaning and live view), but now something else pains me. I saw my 8 GB card fill up in a slow day - and I remembered that this new camera is 14-bit. I took a number of shots at ISOs 6400 and 12800. What are these companies thinking? Why do they bloat the RAW data unnecessarily? ISO 12800 needs about 4 or 5 bits, but the camera is writing 14-bit files, with 9 or 10 bits of incompressible noise. ISO 100 probably can't even make good use of the 13th bit. What a waste of space!

I need to teach a RAW math refresher course to the people at Canon. I'd take a "significant bits" file size reduction at full resolution any day over "sRAW".
06-02-2009, 04:52 PM   #12
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The K20D records info in 14 bits when in the "D" mode i.e. 200 iso.

Ben
06-02-2009, 05:42 PM   #13
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QuoteOriginally posted by benjikan Quote
The K20D records info in 14 bits when in the "D" mode i.e. 200 iso.

Ben
Do you have some more details on this?
06-02-2009, 06:07 PM   #14
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QuoteOriginally posted by jeffkrol Quote
The noise is more than four levels in 14-bit units on all of these cameras
+1
You could have quoted any of my posts on the topic as well ...
As long as the last 1 or 2 bits are random, nothing is lost when truncating additional random bits. However, it is important to keep some noise in the signal (it creates a dither effect important at lower than 100% magnifications).

Now, just go and inspect RGB values at ISO 100 for a uniform surface (like sky). You'll see that only 8-9 Bits are noise free, maybe a bit more for dark surfaces.

QuoteOriginally posted by benjikan Quote
The K20D records info in 14 bits when in the "D" mode i.e. 200 iso.
You keep claiming this. But I think you have been proven wrong by GordonBGood (for the K20D) a long time ago. Also, you never gave a source for your claim (except noting that Chasseur d'Images believes this as well).
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