ichiro17 wrote:
DXO Mark is a joke. Its heavily Nikon biased (maybe its true, but I doubt it) and I don't see any proof their tests are sound. But maybe thats just me?
You need to lose your own personal bias and take an objective look at the results the camera is producing. I don't think there is too much doubt that D3X produces the best IQ ever seen from a 35mm sensor. This can only be a positive thing, regardless of which brand you currently own.
Too many posts to read through to verify the constant misinformation but please be advised:
DXOmark numbers for the Nikon D3x does not say 13.7 stops of DR, it says 13.7 bits of DR. That's what the DR primary number they show is. It's not in stops. View the DR chart and hover your cursor over one of the chart points and it will tell you what the DR in stops is for that ISO.
They rate the D3x at 12.84 stops of dynamic range at 100 ISO (which I highly doubt is really true) but drops quickly at 200 and 400 ISO.
The Canon 5DII and 1DsIII still hold their own just fine.
schweikert wrote:
Too many posts to read through to verify the constant misinformation but please be advised:
DXOmark numbers for the Nikon D3x does not say 13.7 stops of DR, it says 13.7 bits of DR. That's what the DR primary number they show is. It's not in stops. View the DR chart and hover your cursor over one of the chart points and it will tell you what the DR in stops is for that ISO.
They rate the D3x at 12.84 stops of dynamic range at 100 ISO (which I highly doubt is really true) but drops quickly at 200 and 400 ISO.
The Canon 5DII and 1DsIII still hold their own just fine....Show more →
Agreed....the data could be presented in a better manner to avoid confusion.
schweikert wrote:
Too many posts to read through to verify the constant misinformation but please be advised:
DXOmark numbers for the Nikon D3x does not say 13.7 stops of DR, it says 13.7 bits of DR. That's what the DR primary number they show is. It's not in stops. View the DR chart and hover your cursor over one of the chart points and it will tell you what the DR in stops is for that ISO.
They rate the D3x at 12.84 stops of dynamic range at 100 ISO (which I highly doubt is really true) but drops quickly at 200 and 400 ISO.
The Canon 5DII and 1DsIII still hold their own just fine....Show more →
since the light gathering ability of f stops increase by power of 2, and binary digits are also powers of 2, the number of f stops is the same as the number of bits when describing DR.
Agreed that 5D-II and 1DsII are superb cameras, but D3X is better.
I may have to disagree. Take a look at the DR charts of the two cameras. The D3x, supposedly very strong at higher ISO, actually has less DR above ISO 600 than the 5DMII.
andrewd01 wrote:
since the light gathering ability of f stops increase by power of 2, and binary digits are also powers of 2, the number of f stops is the same as the number of bits when describing DR.
Agreed that 5D-II and 1DsII are superb cameras, but D3X is better.
Not true - you cannot make a direct correlation with bits, fstops and DR. The 5D has 12 bits of processing but generally acknowledged to have a DR of about 8 stops. The number of bits used to read out the data has nothing to do with the sensitivity of the sensor and readout electronics.
PS: 13.7 bits of DR? How much more riduculous is that? A bit is on of off. No way to have a fractional bit. Just damned silly...
vachss wrote:
Last I looked the sensors have more than a single pixel, so perhaps statistics may come into play?
Even if that were the case you know what Mark Twain said about statistics; "There are three kinds of lies: Lies, Damned Dies, and Statistics". But no - you cannot assign fractional values to bits. Digital circuitry has a particular number of bits resolution - whole numbers only. The sensor elements are analog - they have a voltage representing the amount of light. The analog voltage is converted to digital with a fixed precision. Now - after they are processed the values can be altered depending on the demosaicing algorithm - but the result is *still* a fixed digital value - rounded up or down depending. Kinda like those fractional pennies banks use - they use them to calculate with but ultimately it's either a penny or not.
Wow! You are comparing the obsolete 21Mp Canon sensor of the 5DMk II and the 1Ds Mk III to Sony/Nikon's latest. Canon's new sensor technology began with the 15Mp 50D crop sensor (which is approx "37Mp" dense if extended to FF).
Nikon has offered a deluxe feature set in the D700 (FF and fine/fast AF). But that's not a technology ranking just a marketing decision (Canon segments their DSLR market differently than Nikon). Canon has a much shorter FF sensor cycle than Sony/Nikon and so, likely, will claim the FF Mp, crown, soon and keep it for some time.
Canon is merely an introduction away from a 30Mp+ FF 1Ds Mk IV (rivaling Leica's, slow shooting, over sized sensored S2) and a 15-18 Mp 1D Mk IV (or even a dual crop sensor).
BubbaJon wrote:
Not true - you cannot make a direct correlation with bits, fstops and DR. The 5D has 12 bits of processing but generally acknowledged to have a DR of about 8 stops. The number of bits used to read out the data has nothing to do with the sensitivity of the sensor and readout electronics.
PS: 13.7 bits of DR? How much more riduculous is that? A bit is on of off. No way to have a fractional bit. Just damned silly...
you are getting confused with the number of bits in the A/D converter vs the number of bits of dynamic range in the analog signal. You would never want to digitise at fewer bits than the analog signal contains, but it is true that many cameras have higher bit-rate A/D converters than the sensors are capable of recording.
The DXO DR is indicative of the DR of the full signal path. In this context f stops and bits are interchangeable in terms of quantifying the DR. Note that the quoted D3X DR is still less than the processing bit-rate of 14-bit.
I recommend the following references to learn more about dynamic range, analog to digital conversion etc:
nathanlake wrote:
I may have to disagree. Take a look at the DR charts of the two cameras. The D3x, supposedly very strong at higher ISO, actually has less DR above ISO 600 than the 5DMII.
yes the 5D-II is better for high ISO performance, whereas the D3X is optimised for best possible DR at low ISO. You pays your money and takes your choice.
andrewd01 wrote:
Not this old chestnut again. Just because monitors and prints can't display 13 stops of DR it doesn't mean the extra DR is not valuable! It's all about the tone mapping choices made in processing. If the camera is not recording detail in the highlights and shadows, you can't pull it out in processing.
Yes, I understand this, but how will you see the difference? Histogram? I didn't say the data wasn't there or didn't matter. I think a 50% increase in DR is quite significant, but I am honestly having trouble "seeing" it. How do you choose your tone map? Visually? ...and displayed how? Please, help me understand.
1Ds IV rivaling the S2? I don't think so. It's like comparing a 35mm SLR to the Pentax 6x7 in the old film days. Apples to oranges. Size matters.
SoundHound wrote:
Canon is merely an introduction away from a 30Mp+ FF 1Ds Mk IV (rivaling Leica's, slow shooting, over sized sensored S2) and a 15-18 Mp 1D Mk IV (or even a dual crop sensor).
andrewd01 wrote:
you are getting confused with the number of bits in the A/D converter vs the number of bits of dynamic range in the analog signal. You would never want to digitise at fewer bits than the analog signal contains, but it is true that many cameras have higher bit-rate A/D converters than the sensors are capable of recording.
The DXO DR is indicative of the DR of the full signal path. In this context f stops and bits are interchangeable in terms of quantifying the DR. Note that the quoted D3X DR is still less than the processing bit-rate of 14-bit.
I recommend the following references to learn more about dynamic range, analog to digital conversion etc:
http://www.cambridgeincolour.com/tutorials/dynamic-range.htm http://www.cambridgeincolour.com/tutorials/bit-depth.htm ...Show more →
Nope - I'm not confused. When you're speaking of DR you use stops - not bits. The number of bits used to digitize the image defines the maximum range of the DR. Since the DR range is limited by the AD range you can correlate the number of bits with the maximum DR range but it is incorrect to assign # of bits to the DR itself. I assure you that I am intimate with the terms and the electronics behind it.
regards,
Jon
Its nothing to do with the AD converter. Dynamic range is the ratio of the largest to smallest signal. This can be expressed in binary notation, and is done so in many articles. Since each f stop lets in twice as much light the DR from a given number of fstops is the number of stops to the power of 2, therefore it corresponds directly with binary notation.
For example two f stops of DR, the largest signal at say f16 , the smallest at say f22, the DR = 2. This value requires two binary digits to record in binary format, so the DR can be expressed as "2 bit"
Now lets consider an image with 3 stops DR (say f22, f16, and f8) f8 gathers 4 times as much light as f22, so the DR is 4. This would require 3 binary digits to represent (100). And so on.
So you see that DR can be expressed as bits, and that the number of bits required to represent the DR is the same as the number of f stops.
I would encourage you to be more open to new concepts given on these forums, you will learn more that way. Everyone has a slightly different background and often concepts that we are familiar with are presented in a slightly different way to which we are used to. Nuff said on the matter.
andrewd01 wrote:
The DXO DR is indicative of the DR of the full signal path. In this context f stops and bits are interchangeable in terms of quantifying the DR. Note that the quoted D3X DR is still less than the processing bit-rate of 14-bit.
So in this case, does the 12.7 (or 13.7 or whatever the quoted number is) stops of DR represent that many recordable stops of exposure in the scene? As in if I took a picture of a scene, and then I spot metered the darkest shadow recorded before the signal is lost in the noise, and the brightest highlight before clipping, the difference between the two spot readings would be 12.7 stops?
I'm aware of the differences between bits of AD, stops, and the fact that just because these cameras have 14 bit converters, they aren't necessarily any better off than they were with 12 bit ADs. I'm just unsure of what DXO means when they say DR. The only DR I really care about is how much of the dynamic range in the scene I can capture. From that point, its easy to map the photo onto the compressed dynamic range of paper, either in Photoshop or in the darkroom.
