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Author Topic: 16 Bit Myth  (Read 58924 times)

Bryan Conner

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Re: 16 Bit Myth
« Reply #100 on: December 31, 2011, 02:08:00 pm »

Why does a person purchase a camera?  To take pictures...unless the person is a collector, or it is purchased as a gift.  But, in the end, most camera purchases are because someone wants to take a picture.  If I were looking to buy a camera and it was advertised as being ANYTHING 16 bit, my first thought would be that it produces 16 bit files.  If it did not produce 16 bit files, then what is the purpose of telling me anything about 16 bit?  This is the same as Audi mentioning the phrase 250 km/h (155 mph) in an advertisement for a basic A2 that will only reach 173 km/h (107 mph).  The Audi A8 will indeed reach 250 km/h and maybe it shares a few electrical connectors or such with the A2.  These parts are capable of reaching 250km/h when they are in the A8, but not the A2.

I do not think that this whole issue is just about one dealer, or one manufacturer.  A lot of companies (not Phase One or related dealers etc) get so caught up in the race to get the customers...some are starting to sound like this: http://www.youtube.com/watch?v=pkYNBwCEeH4  

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rainer_v

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Re: 16 Bit Myth
« Reply #101 on: December 31, 2011, 02:21:02 pm »


Quite possibly. However, back to the original cruxt of stating 16 bits as a specification, if "true" bit depth was stated for every product, it might also lead to confusion, as the stated bit depth from marketing data sheets would likely always differ. So, stating the FTF 4052C as a true 12 bit sensor would confuse, as many other products might genuinely natively be 8 bit, 11 bit, etc. Inacurrate as it may be, 8 bit, 12 bit, 14 bit, 16 bit, etc, are an established reference point. And given the relevance, or lack of relevance if you will, of bit depth as a singular statistic for making a purchasing decision, I don't believe reinventing the wheel when it comes to establishing "true" bit depth for every imaging device on the market is worth the time. And considering I cannot recall the last time I even had a discussion on the bit depth statistic with a client, I would say interested purchasers tend to agree.

steve, the only reason why this 16bit myth has so much relevance is that noone of the manufactors and sellers never has admitted in the various discussions about (e.g. in forums as this one) that his mf backs arent 16bit. as happens now again. rounds and rounds are made without a clear statement, even the dalsa data spec couldnt be more clear as it is..... and even if this was now posted since years. how you can say that you dont see clear if the a22 ( and others ) are 12, 14 or 16bit? its very clear and its easy to see, isnt it? 
next week the 16bit statement will come up again and the same discussion will go on and on, creating this myth which you say is the reason that you have to say its 16bit, because it explains so nice the quality difference between mf and smaller formats.  r.
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Radu Arama

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Re: 16 Bit Myth
« Reply #102 on: December 31, 2011, 02:43:51 pm »

I am not that sure that you will ever find something official from Pentax citing "16 bit pipeline". They quote 14 bit A/D convertor and 14 bit RAW files.

http://www.pentax.jp/english/products/645d/feature_1.html

Happy New Year!
Radu

Even as someone who studied semantics for many years, I still had to pace the floor for a solid 5 minutes to unpack this circuitous defense.

This all started due to an Aptus back that you advertised as having "16 true bits."  This left us scratching our heads about the intended meaning of the word "true."  By implicature, it appeared you were trying to put forth the impression that this back turned out 16 bits of image data, as opposed to 12 or 13 bits of image data and 3-4 bits of noise.  This of course was a false impression.  You wisely decided to correct it, while somehow still defending it.

The manufacturer's technical data sheet supplies a meaning of "true" that is hard to counter.  It claims just over 12 "true bits."  This is not a marketing sheet by the way, but a technical reference with pin-outs and voltages. 

You cite confusion on the part of the prospective customer over varying ratings of bit depth.  You also say that the customer rarely discusses it.  But in point of fact, you try to forestall such discussion by advertising "16 true bits" on your bullet list (as do some of the MF manufacturers in their own marketing literature, e.g., the Pentax 645D).  So by this time, the customer has accepted it unquestioningly as evidenced by the number of times the claim is parroted on these forums.  I would not expect the discussion to come up again unless the customer somehow gets the correct impression that this is not a truthful claim.  You've introduced the confusion you see, a confusion that is not exposed at the point of sale, but later on, in forum threads like this one.  And if the bit specifications were truly inconsequential (both to buyers and in practice), you wouldn't use them in marketing literature.  I don't know what "wheel" you are talking about reinventing here.  And I don't know what kind of "reference point" is established regarding bit depth except those that are intended to induce vague, positive impressions about final image quality in a prospective buyer.

By your lights, all DSLRs might be called 16 bit since they can be made to produce 16 bit files.  In fact, most DSLRs have more "true" bits, considered as measurable dynamic range, than your Aptus.  What your Aptus has, and it does have something special, is something else altogether. 
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LKaven

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Re: 16 Bit Myth
« Reply #103 on: December 31, 2011, 02:49:33 pm »

I am not that sure that you will ever find something official from Pentax citing "16 bit pipeline". They quote 14 bit A/D convertor and 14 bit RAW files.

http://www.pentax.jp/english/products/645d/feature_1.html
I stand corrected.  Thanks for the link.

digitaldog

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Re: 16 Bit Myth
« Reply #104 on: December 31, 2011, 03:37:20 pm »

The problem I have with the semantics: “True 16-bits” (besides the fact it may be untrue which would be inexcusable), is it implies others, competitors have untrue or false 16-bit capture. Talk about two wrongs not making a right!
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Chris_Brown

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Re: 16 Bit Myth
« Reply #105 on: December 31, 2011, 03:49:47 pm »

. . . back to the original cruxt of stating 16 bits as a specification . . .
All that needs to be shown is solid information about the A/D conversion device/algorithm in the product. In audio products for example, the publishing of sample rates and A/D conversion bit depth is the norm.
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LKaven

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Re: 16 Bit Myth
« Reply #106 on: December 31, 2011, 09:30:46 pm »

All that needs to be shown is solid information about the A/D conversion device/algorithm in the product. In audio products for example, the publishing of sample rates and A/D conversion bit depth is the norm.

Oddly enough, according to Dan Lavry, one of the audio industry's eminent A-D designers, there are lots of A-D/D-A converters made with a 24-bit specification, but none of them can actually do more than 21 bits. 

hjulenissen

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Re: 16 Bit Myth
« Reply #107 on: January 01, 2012, 07:58:55 am »

Oddly enough, according to Dan Lavry, one of the audio industry's eminent A-D designers, there are lots of A-D/D-A converters made with a 24-bit specification, but none of them can actually do more than 21 bits. 
This is true.

The audio industry (at least the serious ones) tend to use a term called "effective number of bits". I guess this concept could be used in photography as well, but I would think that established conventions for measuring DR etc directly makes more sense?
http://en.wikipedia.org/wiki/Effective_number_of_bits
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TH_Alpa

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Re: 16 Bit Myth
« Reply #108 on: January 01, 2012, 11:03:02 am »

Just as an information, and for the history and the record, since many wrong information is written here:

It was Sinar who introduced the first MF back with 22 MPx, the Sinarback 54.

At that time, when advertised (launched at Photokina 2002) it was clearly stated in the SINAR brochure, as well as in any relevant published data or technical information, that it was a sensor with a bit depth of 14 bit. I can find the brochure for those who don't believe it. These 14 bit were advertised as well thereafter, when the competition got the 22 MPx sensor from Kodak, in July 2003 (there was a 1 year exclusivity for Sinar).

As a reference for my claim, one can look at Michael's review here, where Sinar clearly stated 14 bit, not like others:

Medium Format Digital Backs — Q3, 2003

Please note also the ISO discrepancy between the different manufacturers (advertised as ISO 25 for Sinar)

Just to put the record straight.

Best regards
Thierry
« Last Edit: January 01, 2012, 11:11:48 am by TH_Alpa »
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Doug Peterson

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Re: 16 Bit Myth
« Reply #109 on: January 01, 2012, 12:14:31 pm »

Dear forum: the graphic graphic containing the five characters found by some to be misleading has been changed. For reference here is the product sheet from Leaf for the Aptus 22.

I will be taking a month or so away from the forum. The overall negative and accusatory (or at least lacking the benefit of the doubt) tone exhibited by some on this thread is absolutely exhausting. If this conversation were at a party I would have left the party a long time ago.

We work very hard to provide honest, meaningful, real-world advice on digital backs. We also strive to provide transparency and open discussion (as indicated in my first reply to this thread); we are in fact real people! I think in this case we were wrong; largely because we (Capture Integration) have always made it part of the company ethos not to rely on manufacturer specs/claims but to provide advice based on actual usage/testing/comparisons. We are not shills selling snake oil - frankly that implication was deeply insulting.

Doug Peterson (e-mail Me)
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« Last Edit: January 01, 2012, 02:46:49 pm by dougpetersonci »
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michael

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Re: 16 Bit Myth
« Reply #110 on: January 01, 2012, 12:58:35 pm »

And that's what we get when some people act like children and boors. A valuable resource is lost, if only for a while.

I will not let this Forum become like DP Review. From now on anyone engaging in insults and personal attacks will be summarily banned. No warnings. I'm fed up.

Michael
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Hulyss

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Re: 16 Bit Myth
« Reply #111 on: January 01, 2012, 01:35:00 pm »

I agree with you, Michael. And Happy new year ;)
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HCHeyerdahl

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Re: 16 Bit Myth
« Reply #112 on: January 01, 2012, 01:54:51 pm »

...
But we are not shills selling snake oil - frankly that implication was deeply insulting.

Doug Peterson (e-mail Me)
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Dear Doug,
I am assuming you are refering to my reply where i used that phrase. I am really sorry to read that you feel deeply insulted. That was certainly not my intention.

I was actually just trying to be helpful, but since english is not my native toung, maybe I don´t have sufficient understanding of all the nuances  that phrase conveys.  Please, let me try again:

I was trying to give an answer to this:
The point is to explain to someone who isn't a scientist why most 22mp backs are better than most 22mp dSLRs. Why pixels are not all created equally. Assume you have about 10 characters worth of space to explain that and the person is not the 5% of users who get deeply involved in the science. "True 16 bit" is about as good as I can come up with as most customers understand the difference between 8 and 16 bits elsewhere in photography. I also considered "Great tonal smoothness" or "holds up to strong styling in post processing well" but it didn't have the same ring and took up much more room. I'm open for suggestions. We're not trying to be dishonest or disingenuous.

I'm serious when I say I'm open for suggestions.


For reference, this is  what I wrote:



As a person considering the jump to MF, my take is that your marketing ought to reflect reality. Thing is when you quote 16 bit as something that makes MF stand out from FF DSLRs,  and threads on several forums find this questionable, I as a potential customer begin to wonder if the whole thing is snake oil. I have spent quite some time trying to sort this out and I am not finished yet... ;)

Now, from what I have managed to pick up from numerous threads it may appear that it is the very size of the sensor itself AND coupled with stricter tollerances in every component that gives MF its alleged superior image quality. If this is actually the case, then this is VERY interesting for a potential customer since this will not be available in a future FF DSLR. Of course DSLRs will continue to evolve, but they will not grow bigger sensors. I also find it unlikely that they will increase their quality tollerances. Hence, at a given purchase date, the benefits from a MF investment will probably hold itself against future FF DSLRs for more than one or two generations (btw a great  wife argument!).

I really don´t have a ready 15 char slogan for you but something along the line of "Built to MF quality tollerances" , "Designed for MF quality" would at least to me suggest that the quality of MF has someting to do with the quality of the entire system.  Sure, lots of people will contest this or similar assertions, but at least we will not have threads from people with superior technical knowledge in image processing, etc more or less PROVING your (16 bit) advantage is wrong.

Hay, OK !  Maybe I still haven´t got it - just my two (amaturish) cents trying to be helpful  ;D.

Christopher


I am a seasoned amature using high end Nikons for a long time and I am considering to make the jump to some MF brand.  I am currently doing my research to determine what advantages MF can give,  and if I need it for my photography.

From several dealers I get the argument that the 16 bits is what gives MF superior file quality. Well, here on LuLA and other forums that assertion is disputed.  That, at least to me, is very confusing and I have spent quite some time trying to figure out what is really the case. Now since this turns out not to be exactly right, I naturally become even more inclined to carefully research other claims about MF too.  Hence, I suggest using some other phrase which conveys accurate information. It would make life a lot easier for me as a researching customer.

I hope you can understand that my argument is NOT about you personally or any other dealer for that matter.  

From your first post I took it that you use the 16 bit argument believing it will convince customers.  I am trying to tell you that at least for for me it does not work.

Sincerely,

Christopher

PS
I see that while writing both Michael and Hulyss have taken offence too. Well, I can just apologize once more. I am truly sorry.
DS
« Last Edit: January 01, 2012, 02:06:18 pm by HCHeyerdahl »
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ErikKaffehr

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Re: 16 Bit Myth
« Reply #113 on: January 01, 2012, 02:39:28 pm »

Hi,

Thanks for posting an interesting link!

Just to put things in perspective:

1) 16 bits corresponds to a DR of 16 steps
2) 16 bits correspond to density 4.8

My film scanner is purported to be 16 bit and have a maximum density of 4.8, pbut it peters out around 3.5 according to independent tests.

Best regards
Erik

Just as an information, and for the history and the record, since many wrong information is written here:

It was Sinar who introduced the first MF back with 22 MPx, the Sinarback 54.

At that time, when advertised (launched at Photokina 2002) it was clearly stated in the SINAR brochure, as well as in any relevant published data or technical information, that it was a sensor with a bit depth of 14 bit. I can find the brochure for those who don't believe it. These 14 bit were advertised as well thereafter, when the competition got the 22 MPx sensor from Kodak, in July 2003 (there was a 1 year exclusivity for Sinar).

As a reference for my claim, one can look at Michael's review here, where Sinar clearly stated 14 bit, not like others:

Medium Format Digital Backs — Q3, 2003

Please note also the ISO discrepancy between the different manufacturers (advertised as ISO 25 for Sinar)

Just to put the record straight.

Best regards
Thierry
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ErikKaffehr

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Re: 16 Bit Myth
« Reply #114 on: January 01, 2012, 02:50:44 pm »

Michael,

Thank you, we all need to calm down.

Best regards
Erik

And that's what we get when some people act like children and boors. A valuable resource is lost, if only for a while.

I will not let this Forum become like DP Review. From now on anyone engaging in insults and personal attacks will be summarily banned. No warnings. I'm fed up.

Michael

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amsp

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Re: 16 Bit Myth
« Reply #115 on: January 01, 2012, 03:41:36 pm »

Six pages of this bs, seriously? Don't you have anything better to do, you know like go out and take some pictures maybe?
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ErikKaffehr

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Re: 16 Bit Myth
« Reply #116 on: January 01, 2012, 03:46:59 pm »

Well, yes, of course! On the other hand, if you want to spend like 30 kUSD you may as well spend it for an existing reason. If you are not interested in this BS, why do you read and why do you post?

Best regards
Erik


Six pages of this bs, seriously? Don't you have anything better to do, you know like go out and take some pictures maybe?
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bjanes

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Re: 16 Bit Myth
« Reply #117 on: January 01, 2012, 04:03:44 pm »

From several dealers I get the argument that the 16 bits is what gives MF superior file quality. Well, here on LuLA and other forums that assertion is disputed.  That, at least to me, is very confusing and I have spent quite some time trying to figure out what is really the case. Now since this turns out not to be exactly right, I naturally become even more inclined to carefully research other claims about MF too.  Hence, I suggest using some other phrase which conveys accurate information. It would make life a lot easier for me as a researching customer.

Rather than reading advertising claims, it is more advisable to understand a bit of basic science and mathematics. A good place to start is the post by Emil Martinec: Noise, Dynamic Range and Bit Depth. Here is an important excerpt that just follows figure 18:

"Quantizing the signal from the sensor in steps much finer than the level of the noise is thus superfluous and wasteful; quantizing the noise in steps much coarser than the level of the noise risks posterization. As long as the noise exceeds the quantization step, the difference between the coarser and finer quantization is imperceptible. As long as noise continues to exceed the quantization step in post-processing, it doesn't matter how one edits the image after the fact, since any squeezing/stretching of the levels also does the same to the noise, which will always be larger than the level spacing no matter how it is squeezed or stretched. On the other hand, quantizing the signal in steps coarser than the noise can lead to posterization. Ideally, the noise should slightly exceed the quantization step, in order that roundoff errors introduced by quantization are negligible, and that no bits are wasted in digitizing the noise."

DXO has a good section on Tonal Range:

"Tonal range is the effective number of gray levels the system can produce. This measure has to take noise into account (indeed, a very thin gray-level quantization is irrelevant if the quantization step is much smaller than noise). The standard deviation of noise can be viewed as the smallest difference between two distinguishable gray levels."


For those who do not like to do integral calculus, consider the following example. Many MFDBs have a full well capacity of 50-60 thousand electrons and the readout is done with a 16 bit ADC, which can theoretically resolve 2^16 or 65536 levels. For simplicity of calculation, assume the full well is 65536 electrons, so each ADC number represents one electron.

A mid gray tone would have a DN (data number) of 0.18*65536 or about 11,800 representing 11,800 electrons. The standard deviation of the shot noise (which places an absolute limit on noise) would be sqrt (11,800) or about 109 electrons representing 109 ADC levels but only one distinguishable gray level. The process could be extended over the range of the sensor to obtain the total number of distinguishable levels. For the Phase One IQ 180, the tonal range is 8.52 bits screen and 10.19 bits print, corresponding to 367 and 1168 levels respectively, a far cry from 65536.

One thing that the IQ 180 does offer that no dSLR can is 81M high quality pixels. If you make big prints, that is a decided advantage, but if you limit yourself to 8x10 inch prints, the difference likely will not be significant from a good dSLR such as the D3x. The proponents of MFDBs do themselves no favor when they quote meaningless statistics such as a true bit depth of 16 or a dynamic range exceeding that of a top dSLR by 6 stops. The proponents also claim that the difference is noticeable at a glance even for 8x10 inch prints, but a double blind study by Michael comparing a good P&S to a MFDB did not bear that out.

Regards,

Bill
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amsp

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Re: 16 Bit Myth
« Reply #118 on: January 01, 2012, 04:05:52 pm »

On the other hand, if you want to spend like 30 kUSD you may as well spend it for an existing reason.

I agree completely, stop arguing about bits, electronics parts and whatnot and go try out the system by taking some actual photographs with it before shilling out 30K. Cause I sure hope people are paying that kind of money because they see a real advantage in the results and not because it says 12, 14 or 16 "bits" on a piece of paper.

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TH_Alpa

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Re: 16 Bit Myth
« Reply #119 on: January 01, 2012, 04:20:35 pm »

That was my experience when demonstrating backs and cameras, that potential customers usually don't blindly believe brochures, but wish to see with their eyes and/or test it themselves.

I think everybody sensed a bit would do that. And by doing real life tests it will definitively show the superiority (wherever this superiority comes from) of a 22 MPx digital MF back, still today, nearly a decade after its introduction. And my guess here is that one does not buy such a capture medium to output only 8x10" prints.

Thierry

... Cause I sure hope people are paying that kind of money because they see a real advantage in the results and not because it says 12, 14 or 16 "bits" on a piece of paper.
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