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#361
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
On Tue, 15 Jan 2019 19:42:49 -0500, Alan Browne
wrote: On 2019-01-15 18:29, Eric Stevens wrote: On Mon, 14 Jan 2019 12:34:42 -0500, Alan Browne wrote: On 2019-01-13 21:07, Eric Stevens wrote: On Sun, 13 Jan 2019 10:06:13 -0500, Alan Browne wrote: On 2019-01-12 21:15, Eric Stevens wrote: On Sat, 12 Jan 2019 09:25:23 -0500, Alan Browne wrote: On 2019-01-11 18:18, Eric Stevens wrote: The recorded output of the ADC is limited by the capabilities of the ADC. But these have no effect on the capabilities of the sensor. If If there is no way to encode the information, then that is the mootest of moot points. That may well be but, as I have several times said, it is possible to scale the dynamic range of the sensor to fit the narrower dynamic range of the ADC. To which I've replied numberous times. In a nutshell, you're trading one form of noise for another. The 'scaling' is done during the conversion of analog to digital in the ADC and involves no more noise than is inherent in any analog to digital conversion. I've pointed out quantization noise to you several times. Ignore it. You ignore everything else. You always get quantization noise when you digitize. That's what I meant by 'inherent'. No. A sample is a sample. It contains signal and _sampling_ source noise (the noise of the thing being sampled and the noise of the ADC), but not quantization noise. In this case we are not considering sampling. We are dealing with digitizing of a static (as in remains constant) charge in the pixel well which has to be digitized as a proportion of the maximum charge when the cell is filled. Quantization noise is an artifact of data manipulation (such as scaling) and is completely unavoidable when doing such operations. Its also inevitable when digitizing an analog signal. See http://www.onmyphd.com/?p=analog.digital.converter under Characteristics of ADCs. -- Regards, Eric Stevens |
#362
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
On Tue, 15 Jan 2019 19:27:35 -0500, nospam
wrote: In article , Eric Stevens wrote: (with today's short focal length lenses) not just short focal length, but all lenses at normal working distances because the difference is too small to matter, below the tolerance of the various components. Your statement is too sweeping. It matters with a 10" lens normally used for used for portraits and it matters more for a 105mm macro lense normally used for dental photography. nope, and dentists don't use 105mm macro lenses anymore. I must tell my dentist. He keeps it alongside his Cerec setup. See https://www.dentsplysirona.com/en/explore/cerec.html I think he is now on his third generation Cerec. but you do it at your peril in macro photography. there is no peril. there's this thing called an exposure meter... TTL avoids the problem there's no need for ttl metering. But it's nice to have, isn't it. all that matters is that the meter knows what the lens is set to. So that it can calculate the effective f-number. I know you will deny that's what it's doing but use your algebra. but if you use an exposure meter you have to know the effective f-number. The nominal f-number is of no use to you. false. On it's own it's no use. -- Regards, Eric Stevens |
#363
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
On Tue, 15 Jan 2019 19:27:36 -0500, nospam
wrote: In article , Eric Stevens wrote: You are still missing the point: lens aperture, shutter speeds or ISOs are not identical to stops. At this point my old physics professor would ask for dimensional analysis. What's the dimensional analysis of "EV" vs "stop" ? First define a stop. use the standard definition. Evasive and unhelpful response. it's not in any way evasive nor is it unhelpful. it's *you* who is evasive, since it's clear you don't know what the definition even is. You don't mean i'm evasive. You mean I'm ignorant. if you prefer, but avoiding answering the question is normally called evasion. YUou wrote words but didn't provide an answer. In communication theory your reply would be classed as noise. In fact I asked you as hopefully you won't argue about your own definition. it's not my definition. Of course not, you avoided giving one. If you mean f-number, a stop is dimensionless. stop and f/stop are not the same. Evasive and unhelpful response. again, it's not in any way evasive nor is it unhelpful. It's unhelpful in that it is meaningless in the context of the question. it's not at all meaningless. they are not the same. very simple. it doesn't get any clearer than that. If you mean sqrt(2) a stop is dimensionless. If you mean 1/sqrt(2) a stop is still dimensionless. Basically EV = Constant, or (Shutter Speed) x f-number = another constant. The dimensions of (Shutter Speed) are 1/T, f-number is dimensionless, so the dimensions of EV should be 1/T. nope. Evasive and unhelpful response. your repetition is what's evasive an unhelpful. Mere denial is not helpful. then why do you do it? -- Regards, Eric Stevens |
#364
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
On Tue, 15 Jan 2019 19:43:58 -0500, Alan Browne wrote: On 2019-01-15 18:46, Eric Stevens wrote: On Tue, 15 Jan 2019 01:17:18 -0500, nospam your repetition is what's evasive an unhelpful. Mere denial is not helpful. Yet that's all you do by repeating the same erroneous facts and conclusions. false. ... or no. That's what I call denial. -- Regards, Eric Stevens |
#365
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Finally got to the point where no new camera holds my interest(waiting for specific offering)
On 2019-01-16 23:43, Eric Stevens wrote:
On Tue, 15 Jan 2019 19:42:49 -0500, Alan Browne wrote: On 2019-01-15 18:29, Eric Stevens wrote: On Mon, 14 Jan 2019 12:34:42 -0500, Alan Browne wrote: On 2019-01-13 21:07, Eric Stevens wrote: On Sun, 13 Jan 2019 10:06:13 -0500, Alan Browne wrote: On 2019-01-12 21:15, Eric Stevens wrote: On Sat, 12 Jan 2019 09:25:23 -0500, Alan Browne wrote: On 2019-01-11 18:18, Eric Stevens wrote: The recorded output of the ADC is limited by the capabilities of the ADC. But these have no effect on the capabilities of the sensor. If If there is no way to encode the information, then that is the mootest of moot points. That may well be but, as I have several times said, it is possible to scale the dynamic range of the sensor to fit the narrower dynamic range of the ADC. To which I've replied numberous times. In a nutshell, you're trading one form of noise for another. The 'scaling' is done during the conversion of analog to digital in the ADC and involves no more noise than is inherent in any analog to digital conversion. I've pointed out quantization noise to you several times. Ignore it. You ignore everything else. You always get quantization noise when you digitize. That's what I meant by 'inherent'. No. A sample is a sample. It contains signal and _sampling_ source noise (the noise of the thing being sampled and the noise of the ADC), but not quantization noise. In this case we are not considering sampling. We are dealing with digitizing of a static (as in remains constant) charge in the pixel well which has to be digitized as a proportion of the maximum charge when the cell is filled. Quantization noise is an artifact of data manipulation (such as scaling) and is completely unavoidable when doing such operations. Its also inevitable when digitizing an analog signal. Which you clearly don't understand. The link you pointed to was referring to quantization noise in the frequency domain, not the amplitude which is the issue at hand here. I was clearly referring to noise introduced by scaling or manipulation (amplitude). But you will continue to hunt for anything that violates the notion that there is more information in 14 bits than there is in 14 bits. There isn't. There can't be. -- "2/3 of Donald Trump's wives were immigrants. Proof that we need immigrants to do jobs that most Americans wouldn't do." - unknown protester |
#366
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
In article , Eric Stevens
wrote: (with today's short focal length lenses) not just short focal length, but all lenses at normal working distances because the difference is too small to matter, below the tolerance of the various components. Your statement is too sweeping. It matters with a 10" lens normally used for used for portraits and it matters more for a 105mm macro lense normally used for dental photography. nope, and dentists don't use 105mm macro lenses anymore. I must tell my dentist. He keeps it alongside his Cerec setup. See https://www.dentsplysirona.com/en/explore/cerec.html I think he is now on his third generation Cerec. this is not a 105mm macro lens: https://www.dentsplysirona.com/en/explore/cerec/scan-with-cerec.html but you do it at your peril in macro photography. there is no peril. there's this thing called an exposure meter... TTL avoids the problem there's no need for ttl metering. But it's nice to have, isn't it. sure, but the point is that it's not required. all that matters is that the meter knows what the lens is set to. So that it can calculate the effective f-number. I know you will deny that's what it's doing but use your algebra. if it's not ttl metering, then that is what it's probably doing, but if it is ttl, then it can measure the *actual* light hitting the sensor. either way, there is no peril. it 'just works'. but if you use an exposure meter you have to know the effective f-number. The nominal f-number is of no use to you. false. On it's own it's no use. nor is a lens. |
#367
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
In article , Eric Stevens
wrote: also, their 'tests' claim what is physically impossible, making them untrustworthy and their scale is whatever they want it to be, with newer cameras scoring higher and higher. Suspicion and innuendo. That's not evidence. the evidence is quite clear that they cannot be trusted *at* *all*. The evidence appears to be that you can/will not produce any evidence to support that statement. false, there is extensive evidence that dxo is a sham, but as usual, you refuse to acknowledge that and just want to argue, now having resorted to ad hominem attacks, as usual. their 'tests' claim what is physically not possible. that alone makes them a scam Example? - assuming of course that you are able to cite one. of course i'm able. i do not make false claims. period. --- Claim by nospam: ---- dxo measured 14.8 stops of dynamic range on the nikon d810 and d850, which is *higher* than the theoretical maximum of 14 stops (14 bit a/d) and in the real world, it won't actually get 14 stops. that's not *my* claim. it's basic sampling theory, something which you clearly do not understand at all. I challenged this comment which lead to an enormous thread which fanned out in all directions. My contention was (and is) that the number of bits that are used to code an image have nothing to do with the dynamic range of the sensor. You can code it with as many bits as you like with factors other than dynamic range determining the choice. In particular there is no reason why a sensor should not have a dynamic range wider than implied by the number of bits with which it's output is encoded. your contention is wrong, which you even admitted in the middle of the thread. At one stage Ron C suggested I should explain my views with diagrams. With some reluctance I have been getting round to doing this. Preparing the diagrams so as to be able to deal with nospams of tghis world is no mean task. In the course of my background research I found the following thread from dpreview dated Mar 25, 2012. https://www.dpreview.com/forums/thread/3170233 If you read that you will see that the maximum number of bits with which it is worthwhile coding an image is determined by (a) read noise and (b) pixel well size. DR vs number of bits is touched upon but no one has suggested that sensor DR is limited by bit number. the second post in that thread clearly does, further proof that you don't understand the topic. I also came across http://www.onmyphd.com/?p=analog.digital.converter which is a good summary of the basics of analog to digital convertors (ADC). Under the heading "What is an analog-digital convertor" the author has written: "An Analog-Digital Converter (ADC) is a widely used electronic component that converts an analog electric signal (usually a voltage) into a digital representation. The ADCs are at the front-end of any digital circuit that needs to process signals coming from the exterior world. ..... ---- complex text snipped ---- Therefore, more bits leads to more precision in the digital representation. Here we simplify the range to be between 0 and Vref, although the range may be between any two values." That last has always been my point. What is being encoded is a signal between gthe upper and lower limits to the sensitivity of the sensor. Their mathematical relationship (as in their ratio = dynamic range) does not come into the question. it is only their difference which matters. still not getting it. I'm not going to write any more about the original argument. nospam can go and find another playmate. I may be tempted to come back in if a sensible and rational discussion of a new aspect gets under way. Other than tghat I've finished with this thread. ad hominem, and it isn't just me who has been telling you that you're wrong. come back after you've learned about sampling theory. only then can there be a rational discussion. |
#368
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
In article , Eric Stevens
wrote: You are still missing the point: lens aperture, shutter speeds or ISOs are not identical to stops. At this point my old physics professor would ask for dimensional analysis. What's the dimensional analysis of "EV" vs "stop" ? First define a stop. use the standard definition. Evasive and unhelpful response. it's not in any way evasive nor is it unhelpful. it's *you* who is evasive, since it's clear you don't know what the definition even is. You don't mean i'm evasive. You mean I'm ignorant. if you prefer, but avoiding answering the question is normally called evasion. YUou wrote words but didn't provide an answer. In communication theory your reply would be classed as noise. i *did* provide an answer. you don't like the answer because it shows you to be wrong. your dislike does not constitute evasion. it's also an ad hominem attack, and since you're very much in over your head, it's all you can do. In fact I asked you as hopefully you won't argue about your own definition. it's not my definition. Of course not, you avoided giving one. false. If you mean f-number, a stop is dimensionless. stop and f/stop are not the same. Evasive and unhelpful response. again, it's not in any way evasive nor is it unhelpful. It's unhelpful in that it is meaningless in the context of the question. it's not at all meaningless. they are not the same. very simple. it doesn't get any clearer than that. If you mean sqrt(2) a stop is dimensionless. If you mean 1/sqrt(2) a stop is still dimensionless. Basically EV = Constant, or (Shutter Speed) x f-number = another constant. The dimensions of (Shutter Speed) are 1/T, f-number is dimensionless, so the dimensions of EV should be 1/T. nope. Evasive and unhelpful response. your repetition is what's evasive an unhelpful. Mere denial is not helpful. then why do you do it? and as expected, you are ignoring the actual topic. that's called evasion. |
#369
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Finally got to the point where no new camera holds my interest(waiting for specific offering)
On 2019-01-17 09:22, Alan Browne wrote:
The link you pointed to was referring to quantization noise in the frequency domain, not the amplitude which is the issue at hand here. Ooops... I should have said "time domain". -- "2/3 of Donald Trump's wives were immigrants. Proof that we need immigrants to do jobs that most Americans wouldn't do." - unknown protester |
#370
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Finally got to the point where no new camera holds my interest (waiting for specific offering)
On Thu, 17 Jan 2019 09:22:21 -0500, Alan Browne
wrote: On 2019-01-16 23:43, Eric Stevens wrote: On Tue, 15 Jan 2019 19:42:49 -0500, Alan Browne wrote: On 2019-01-15 18:29, Eric Stevens wrote: On Mon, 14 Jan 2019 12:34:42 -0500, Alan Browne wrote: On 2019-01-13 21:07, Eric Stevens wrote: On Sun, 13 Jan 2019 10:06:13 -0500, Alan Browne wrote: On 2019-01-12 21:15, Eric Stevens wrote: On Sat, 12 Jan 2019 09:25:23 -0500, Alan Browne wrote: On 2019-01-11 18:18, Eric Stevens wrote: The recorded output of the ADC is limited by the capabilities of the ADC. But these have no effect on the capabilities of the sensor. If If there is no way to encode the information, then that is the mootest of moot points. That may well be but, as I have several times said, it is possible to scale the dynamic range of the sensor to fit the narrower dynamic range of the ADC. To which I've replied numberous times. In a nutshell, you're trading one form of noise for another. The 'scaling' is done during the conversion of analog to digital in the ADC and involves no more noise than is inherent in any analog to digital conversion. I've pointed out quantization noise to you several times. Ignore it. You ignore everything else. You always get quantization noise when you digitize. That's what I meant by 'inherent'. No. A sample is a sample. It contains signal and _sampling_ source noise (the noise of the thing being sampled and the noise of the ADC), but not quantization noise. In this case we are not considering sampling. We are dealing with digitizing of a static (as in remains constant) charge in the pixel well which has to be digitized as a proportion of the maximum charge when the cell is filled. Quantization noise is an artifact of data manipulation (such as scaling) and is completely unavoidable when doing such operations. Its also inevitable when digitizing an analog signal. Which you clearly don't understand. The link you pointed to was referring to quantization noise in the frequency domain, not the amplitude which is the issue at hand here. I was clearly referring to noise introduced by scaling or manipulation (amplitude). But you will continue to hunt for anything that violates the notion that there is more information in 14 bits than there is in 14 bits. There isn't. There can't be. Frequency or amplitude: the principle is the same. I have never argued that "there is more information in 14 bits than there is in 14 bits". As you say, there can't be. What I have said from the beginning is that an analog signal of _any_dynamic_range_ can be coded in 14 bits. There is no reqirement imposed on the DR of the source device. I have said this in so many ways so many times that I'm not going to try and repeat it any more. -- Regards, Eric Stevens |
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