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8 bit vs 12 bit

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Steve Phillipps

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According to the specs the Sony FS700 has 8 bit processing and recording, while the Scarlet is 12 bit, correct?
This doesn't make too many headlines but it could it be a big factor in image quality?
Am I right in thinking that dynamic range and the gradation between areas of different brightness is what will be affected - and things like highlight handling?
Steve
 
8 bit = 256 discrete "parts" or levels; 16 bit > 64,000 discrete "parts" or levels. Slightly better. :-)
 
Bob Gundu said:
Most visible difference is in banding.
Click to expand...

And, in comparison 8-bits can look relatively posterized. :-) A poorly exposed 8-bit blue Chanel goes blocky and looks more like alien measles than it's 16-bit counterpart. =-)
 
Of course is slightly better 10 bit then 8bit (or processing in 16 etc). But this is not the only think U have to think about minus and plus about camera systems. Yes, FS700 is only 8 bit, but try to shoot with very poor or available light and do it after with the Scarlet or the Epic... U'll figure out an HD videofile vs a VHS (maybe a little more). So U have to think about the sensibility of the newer sensor. In the other hand under control light, more bits U got better U'll work with the highlights.... and more room for post, more colours, better codec (far better)... so the bad, looking at that, is not too bad regarding the pros...
Of course everything depends on what's the use of the camera. At the end, infact, if U want to shoot movies, U have to light (also if U're using a fs100/700).
 
Steve Phillipps said:
According to the specs the Sony FS700 has 8 bit processing and recording, while the Scarlet is 12 bit, correct?
This doesn't make too many headlines but it could it be a big factor in image quality?
Am I right in thinking that dynamic range and the gradation between areas of different brightness is what will be affected - and things like highlight handling?
Steve
Click to expand...


differences are quite huge. question is how are you seeing the footage.

8 bit is 255x255x255 colors = about 16.7 million colors
it is also how most screens, TVs, monitors and projectors show.

10 bit is 1024x1024x1024 colors = roughly 1 bilion colors
and how high-end equipment such as broadcast grading monitors and very expensive computer screens work.
also how ProRes, DNxHD and Cineform store color data

12 bit is 4096x4096x4096 colors = about 67 bilion colors (i'm remembering this, not calculating, so may be off by a bit)
very high end digital projection (REDRAY projector for instance) and high-end image sequence files, as well as the wonderful
ProRes 4x4.

16 bit is a lot... :) 65000 levels, and i believe only film scans and laser prints use this level of color depth.
I don't think there is a digital way to see 16 bits of color.

about the banding.
I remember reading something about the fact that most viewers could notice banding in screenings of 8 bit
and a large number could notice 10 bit banding, but only 1% or so could see it in 12 bits.

more important than shooting at high color depth is retaining it throughout post workflows and not truncating down to lower depth.
it will have major influence on color grading, keying, and future generations of the final file.


FS700, which in my opinion is nothing more than an overpriced toy, is not only 8 bit its 4:2:0 too... which by itself sucks much more than 8 bits. i even remember that like the FS100, it does not output 10 bit out of SDI/HDMI... might be wrong on that.

hope this helps


hector
 
Hector Berrebi said:
more than an overpriced toy, is not only 8 bit its 4:2:0 too... which by itself sucks much more than 8 bits. i even remember that like the FS100, it does not output 10 bit out of SDI/HDMI... might be wrong on that.
hector
Click to expand...

No, I think you're right, it is only 8 bit out. But presumably as its processing is all 8 bit anyway there'd be no use outputting 10 bit anyway as the data has already been lost?
Steve
 
Steve Phillipps said:
No, I think you're right, it is only 8 bit out. But presumably as its processing is all 8 bit anyway there'd be no use outputting 10 bit anyway as the data has already been lost?
Steve
Click to expand...

I don't think the processing is 8 bit. this makes no sense.
8 bits refer to the AVCHD file it produces, as well as the truncated signal out of the HD-SDI.
this is a stupid strategy employed by SONY, CANON and PANASONIC to limit their cheaper cameras, and by that protect the more expensive ones capable of 10 bit output.

problem is, cameras like the C300, or FS700 are not really cheap... yet they are still limited,

and as the 4-5 years old EX3 already had 10 bit HD-SDI output, it makes it even more ridiculous

maybe they don't know how to deal with the outburst of affordable external recorders capable of 10 bit in recent years.

in the C300 it hits new records of stupid, as when you connect it to an external recorder, all you gain is extra Mbs compared to the 4:2:2, 8 bit internal signal...

at least the FS700 ups you to 4:2:2 on HD-SDI :)
 
Last edited:
According to Alister Chapman's review it is 8 bit DSP. I always try to look for a reason why something seems so good and yet so "cheap", maybe that's it?
Steve
 
It is worth noting, however, that REDCODE RAW records 16bits per pixel linear (from what I understand), whereas the FS700 records 8bits per channel with 3 channels gamma corrected. It is definitely not as simple as 8bit YUV vs 16bit RAW or 16bit RAW vs 24bit RGB or whatever you want to call them. You can make numerical comparisons, for example, with 8bit RGB such as that coming out of the FS700's HDMI port (which is 444/RGB but difficult to actually capture, and subsampled chroma 422 and 420 are even more difficult to compare directly). The FS700's 8bits per channel with 3 channels per pixel or 24bits per pixel, gives 16.7million levels per RGB pixel. On the other hand, the pixels stored by RED's RAW are 16bit and only one color channel per pixel so they give 65,536 levels per RAW pixel.

12-16bit RAW is extremely necessary for linear sensor data, especially with post gain/ISO. The shadow detail is stored with much less precision than the midtones and midtones much less than the highlights.

It might be interesting to do tests on primary color gradients to see how they compare. I imagine Scarlet would do much better than an FS700 for banding up to a certain ISO and then drop off quite a bit, but on the other hand, at that point, at a high ISO, any posterization in Scarlet's images would likely be masked by unbearable noise and impractical due to unusable images anyway.
 
Noah Yuan-Vogel said:
It is worth noting, however, that REDCODE RAW records 16bits per pixel linear (from what I understand), whereas the FS700 records 8bits per channel with 3 channels gamma corrected. It is definitely not as simple as 8bit YUV vs 16bit RAW or 16bit RAW vs 24bit RGB or whatever you want to call them. You can make numerical comparisons, for example, with 8bit RGB such as that coming out of the FS700's HDMI port (which is 444/RGB but difficult to actually capture, and subsampled chroma 422 and 420 are even more difficult to compare directly). The FS700's 8bits per channel with 3 channels per pixel or 24bits per pixel, gives 16.7million levels per RGB pixel. On the other hand, the pixels stored by RED's RAW are 16bit and only one color channel per pixel so they give 65,536 levels per RAW pixel.

12-16bit RAW is extremely necessary for linear sensor data, especially with post gain/ISO. The shadow detail is stored with much less precision than the midtones and midtones much less than the highlights.

It might be interesting to do tests on primary color gradients to see how they compare. I imagine Scarlet would do much better than an FS700 for banding up to a certain ISO and then drop off quite a bit, but on the other hand, at that point, at a high ISO, any posterization in Scarlet's images would likely be masked by unbearable noise and impractical due to unusable images anyway.
Click to expand...


From what I understand REDCODE RAW records 16bits per pixel linear per channel with 3 channels
 
Noah Yuan-Vogel said:
It is worth noting, however, that REDCODE RAW records 16bits per pixel linear (from what I understand), whereas the FS700 records 8bits per channel with 3 channels gamma corrected. It is definitely not as simple as 8bit YUV vs 16bit RAW or 16bit RAW vs 24bit RGB or whatever you want to call them. You can make numerical comparisons, for example, with 8bit RGB such as that coming out of the FS700's HDMI port (which is 444/RGB but difficult to actually capture, and subsampled chroma 422 and 420 are even more difficult to compare directly). The FS700's 8bits per channel with 3 channels per pixel or 24bits per pixel, gives 16.7million levels per RGB pixel. On the other hand, the pixels stored by RED's RAW are 16bit and only one color channel per pixel so they give 65,536 levels per RAW pixel.

12-16bit RAW is extremely necessary for linear sensor data, especially with post gain/ISO. The shadow detail is stored with much less precision than the midtones and midtones much less than the highlights.

It might be interesting to do tests on primary color gradients to see how they compare. I imagine Scarlet would do much better than an FS700 for banding up to a certain ISO and then drop off quite a bit, but on the other hand, at that point, at a high ISO, any posterization in Scarlet's images would likely be masked by unbearable noise and impractical due to unusable images anyway.
Click to expand...

I have absolutely no idea what any of that means!! :confused1: :smiley:
 
Steve Phillipps said:
I have absolutely no idea what any of that means!! :confused1: :smiley:
Click to expand...

You only need to understand the bit that says "It is definitely not as simple as 8bit YUV vs 16bit RAW or 16bit RAW vs 24bit RGB". Number of bits is meaningless out of a detailed technical context!
 
To get a very rough idea of the sorts of issues that might happen, if you get an image say of a sunset or blue sky shot, something with a finely graduated back ground, display it on your computer screen then change the display from millions of colours to hundred of colours all will beome clear....not........
 
Steve Phillipps said:
According to the specs the Sony FS700 has 8 bit processing and recording, while the Scarlet is 12 bit, correct?
This doesn't make too many headlines but it could it be a big factor in image quality?
Am I right in thinking that dynamic range and the gradation between areas of different brightness is what will be affected - and things like highlight handling?
Steve
Click to expand...

The key take away is you need at least 10-bit depth (i.e. precision) in your recording to avoid visible banding in smooth graduated backgrounds. Higher bit depth is important if you intend to do extensive color correction, so that you can maintain that minimum precision even after pushing and pulling the data around.

Which is why RED has always done at least 12-bit precision recording. Recording RAW v's YCbCr is not relevant to the above...
 
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