"Equivalence" demonstrated: Canon 5D and Panasonic GX1

Started Apr 27, 2013 | Discussions
echelon2004 Veteran Member • Posts: 8,128
Re: There is no accepted definition of "equivalent images"
2

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

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Anders
'It is nice to be important but it is more important to be nice'

John King
John King Forum Pro • Posts: 14,941
Re: There is no accepted definition of "equivalent images"

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

-- hide signature --

Anders
'It is nice to be important but it is more important to be nice'

I think that you have said everything that needs to be said about this subject - in a single nutshell.

Simple, succinct, correct.

Well done.

-- hide signature --

Regards, john from Melbourne, Australia.

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Ulric Veteran Member • Posts: 4,532
Re: 'Equivalent' can mean many different things
2

boggis the cat wrote:

Great Bustard wrote:

Thus, I see no reason not to use the word "equivalent" to describe photos that have the same perspective, framing, DOF, shutter speed, and display size even when other elements of IQ are not necessarily the same.

'Equivalent' does not have the narrow meaning that you may prefer it to have.

I had this very conversation only yesterday.
GB: "Addition goes like this: you add two numbers and the result is 5."
U: "What? It depends on the numbers, the result can be anything."
GB: "The numbers are 2 and 3. It says so on my blog."
U: "What if the numbers are 2 and 4?"
GB: "Why am I constantly being misrepresented? The result is 5 because the numbers are 2 and 3!"
U: "Have you considered making up a name for the process of adding these particular numbers, to distinguish from addition in general?"
GB: [googles addition and cuts and pastes definition from online dictionary] "Is there something else you want me to explain?"
U: [goes to bed]

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Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: Rough, Qualified Approximations Surrounding Settings
3

pidera wrote:

It is exactly these differences one sees when comparing images made using equivalent settings that make "equivalency" interesting, as they go beyond the obvious conclusions. The use of equivalent settings allows to really see difference in distortion, out of focus behaviour, sensor performance etc. That is why I prefer not to talk about equivalent images, lenses etc but merely about equivalent settings.

I agree. Attempting to grab the word "equivalent" and sling it wide as if it could encompass all realms of subjective perceptual aesthetics seems about as productive as expecting listeners of music to gather in committee and legislate precisely what musical intervals, scales, timbres, instruments, artists, and musical pieces are "better", "the same", or "worse". Aesthetics is not in itself a science.

That is a truly fool's errand, and a prescription for pretentious qualitative subjective declarations rendered meaningless when one rationally considers the lack of scruples of those who would expect to shove their subjective perceptions, preferences, and tastes down the throats of others.

There is no way that I can step into the heads of others and look through their eyes. And the reverse is also true. Therefore, such "qualitative" debates are implicilty based upon falacious premises. Why this simple but most profound variable is so commonly ignored is an eternal mystery.

It makes more sense to critique a quantitative argument on the quantitative bases themselves - and the recognizable complexities surrounding attempting to project them into qualitative perceptual realms. However, fuzzy edges do not necessarily entirely negate their (qualified) usefulness.

.

There are certain quantitative characteristics arising out of camera-lens system settings that are measurable (with varying degrees of complexity, for the most part not without aid of instrumentation).

Field of View - Easy to determine (but not as simple as Focal Length when focused at infinity).

Depth of Field - Possible to determine (but varies with any given individual viewers' visual acuity).

Signal/Noise Ratio - Possible to determine (but varies in perceived impact dependent upon the image itself, viewing conditions, and individual viewers, especially where it comes to periodic noise).

.

When we use simplified models that replace complex multi-element lens-systems with single, symmetrical thin lenses, a number of rough approximations are made when scaling settings.

(1) Effective Focal Length should be used instead of the Focal Length when focused at infinity.

(2) Scaling Focal Length as well as the F-Ratio by the ratio of the sensor Crop Factors ignores the fact that the Depth of Field (also) changes as a function of the ratio of the Camera (lens-system front nodal plane) to Subject (plane of focus) Distance to the Hyperfocal Distances involved - by an amount directly proportional to the ratio of the Focal Lengths of compared systems.

Therefore, the inter-format transformations made are only valid when the Camera to Subject Distance is substantially longer than the Focal Length, and are also only valid when the Camera to Subject Distance is substantially shorter than any of the Hyperfocal Distances involved.

(3) The relationships of image-noise to sensor size are valid only for Photon Shot Noise when the relative Quantum Efficiencies are known and also factored-in. The additional element, that is ...

... Read Noise (even the entirely random, and not periodic components of), is design-specific in nature, and does appear to reliably follow simplistic assumptions regarding scaling with photosite geometries. Further, the magnitude of (input-referred) Read Noise as well as its (output-referred) proportion (relative to the maximum recorded or recordable peak level) is camera system specific, and is thus a complicated and individualized function of ISO settings.

Therefore, quite a bit of specific actual test-data and knowledge is required in order to meaningfully make such comparisons and assumptions surrounding Signal/Noise Ratio - and such numerical comparisons may not necessarily accurately reflect viewers' subjective perceptions.

I recently proposed referring to such rough corollaries as "metametric" as opposed to "equivalent":

http://www.dpreview.com/forums/post/51322339

... but the participants involved in that particular discussion seemed too embroiled to pay attention.

.

If the interesting and somewhat useful methods of (approximate) comparison of camera-lens systems that King James (among others) ascribe to should rightly be qualified, it is for the above reasons.

However, it seems that the more common challenge arises out of seriously misguided viewpoints seemingly unwilling (or unable) to recognize the relatively straightforward and easily demonstrable differences between: Entrance Pupil Diameter and F-Ratio; Exposure proper (which has nothing to do with ISO Sensitivity) and its clear misuse when referring to Brightness; the difference between light energy per unit area (intensity) and light energy per unit image-sensor active-area (total light); and the relationship of sensor-area to Photon Shot Noise SNR.

When people are unable to grasp the fundamental principles upon which such comparisons are based, the surrounding discussions are as a result virtually doomed to ever resemble conga-lines of vociferous drop-outs from a remedial reading class insisting to teacher that up is down and 2+2=5 - and such discussions seldom transcend the painful review exercises of the first day of class.

What ensues more resembles some kind of series of belligerent assaults upon teacher - and it may be that King James is most comfortable presiding over introductory classes. No other venue attracts so may who are often in some way misguided or outright wrong to be duly corrected. A perhaps gratifying position for magister - as he able to always feel comfortably ahead of his audience.

And the insurgency should not forget that such socratic festivities are not a required course - it is they who take up the gauntlet with intention to unseat the self-proclaimed champ. The most prevalent "equivalence" that I see being assumed is one between public power and providential majesty. All who aspire to such social status face never-ending challenges to their perceived title.

DM ...

Detail Man
Detail Man Forum Pro • Posts: 16,789
Addendum: Rough, Qualified Approximations Surrounding Settings

Detail Man wrote:

There are certain quantitative characteristics arising out of camera-lens system settings that are measurable (with varying degrees of complexity, for the most part not without aid of instrumentation).

Field of View - Easy to determine (but not as simple as Focal Length when focused at infinity).

Depth of Field - Possible to determine (but varies with any given individual viewers' visual acuity).

Diifraction - Intertwined with photosite aperture/pitch and AA filter in composite MTF response.

Signal/Noise Ratio - Possible to determine (but varies in perceived impact dependent upon the image itself, viewing conditions, and individual viewers, especially where it comes to periodic noise).

.

When we use simplified models that replace complex multi-element lens-systems with single, symmetrical thin lenses, a number of rough approximations are made when scaling settings.

(1) Effective Focal Length should be used instead of the Focal Length when focused at infinity.

(2) Scaling Focal Length as well as the F-Ratio by the ratio of the sensor Crop Factors ignores the fact that the Depth of Field (also) changes as a function of the ratio of the Camera (lens-system front nodal plane) to Subject (plane of focus) Distance to the Hyperfocal Distances involved - by an amount directly proportional to the ratio of the Focal Lengths of compared systems.

Therefore, the inter-format transformations made are only valid when the Camera to Subject Distance is substantially longer than the Focal Length, and are also only valid when the Camera to Subject Distance is substantially shorter than any of the Hyperfocal Distances involved.

While it is true that in equal-framing (FOV) conditions (where Focal Length scales with the ratio of Crop Factors), and at any given Wavelength, diffraction (Airy disk) dimensions will also scale with Crop Factor (and thus represent the same proportional linear dimensions of the Image Sensor) ...

... the effects of diffraction upon the composite system MTF are nevertheless related to the product of Wavelength multiplied by F-Ratio (a spatial distance) as it compares to its combination (convolution) with the photosite aperture/pitch and AA filter beam-displacement ...

... and no increases in photosite density will make any difference in the composite system MTF at spatial frequencies at or beyond composite system MTF response extinction (existing at a spatial frequency equal to the reciprocal of the spatial dimension that is the product of Wavelength multiplied by F-Ratio).

The above relationship is somewhat more complicated in the case of a Bayer-arrayed/filtered Image Sensor - but remains one that is not fundamentally altered by increases in photosite density.

(3) The relationships of image-noise to sensor size are valid only for Photon Shot Noise when the relative Quantum Efficiencies are known and also factored-in. The additional element, that is ...

... Read Noise (even the entirely random, and not periodic components of), is design-specific in nature, and does appear to reliably follow simplistic assumptions regarding scaling with photosite geometries. Further, the magnitude of (input-referred) Read Noise as well as its (output-referred) proportion (relative to the maximum recorded or recordable peak level) is camera system specific, and is thus a complicated and individualized function of ISO settings.

Therefore, quite a bit of specific actual test-data and knowledge is required in order to meaningfully make such comparisons and assumptions surrounding Signal/Noise Ratio - and such numerical comparisons may not necessarily accurately reflect viewers' subjective perceptions.

boggis the cat Veteran Member • Posts: 6,329
Re: I agree !
1

pidera wrote:

Yes I agree with your observations that the g7 results look slightly better and that this is probably due to the camera and lens operating at settings for which it is optimised (unlike the FF setup at iso 1600 and f/22).

This does of course point to a likely slight to serious 'mismatch' issue when assuming that 'equivalent photographs' or 'the same total light' will turn out in a real situation exactly as predicted.  If the sensor sizes are greatly different then the assumptions probably break down quickly.

After thinking about this a bit, it is surprising to me that the G7 does so well, optically.  This makes me suspicious of software 'corrections'.  It does appear that the 5D shot may have more detail while being noisier.

Perhaps the trick in closing this gap in a convincing manner is in the image processing.  As time goes on, we can expect sensor capability to plateau and optics to be pared down as much as feasible.  More processing power will lead to manufacturer's moving to (likely competing) 'fake' modifications to the captured data.  Some of the DOF effects available in software now are pretty convincing, as an example.

Maybe in five years time the arguments on these forums will be about which manufacturer's processing engine and AI scene recognition optimisations are the best, and tawdry stuff like sensors and optics will be largely ignored. 

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Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: There is no accepted definition of "equivalent images"
3

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

Since camera to subject distance ("perspective") is held constant in the comparisons that King James makes, the entire premise of your technical point seems to evaporate into misty dewdrops ...

boggis the cat Veteran Member • Posts: 6,329
Yes, 'a failure to communicate'...
2

Ulric wrote:

boggis the cat wrote:

Great Bustard wrote:

Thus, I see no reason not to use the word "equivalent" to describe photos that have the same perspective, framing, DOF, shutter speed, and display size even when other elements of IQ are not necessarily the same.

'Equivalent' does not have the narrow meaning that you may prefer it to have.

I had this very conversation only yesterday.
GB: "Addition goes like this: you add two numbers and the result is 5."
U: "What? It depends on the numbers, the result can be anything."
GB: "The numbers are 2 and 3. It says so on my blog."
U: "What if the numbers are 2 and 4?"
GB: "Why am I constantly being misrepresented? The result is 5 because the numbers are 2 and 3!"
U: "Have you considered making up a name for the process of adding these particular numbers, to distinguish from addition in general?"
GB: [googles addition and cuts and pastes definition from online dictionary] "Is there something else you want me to explain?"
U: [goes to bed]

Yes, there does seem to be a disconnect somewhere.  But not like a cultural gap or misunderstanding -- more like trying to communicate with an alien species.

I thought that Joe had agreed to clarifying his pet concept, after a verylarge number of back and forth threads on the OSTF.  Simply changing 'equivalence' to 'equivalent photographs' doesn't seem a huge ask, and makes it a bit clearer what the intent is.  It would be preferable to follow the exposure v total light path to get to the basic idea that 'more light is better, all else being equal', simply because everyone will tend to understand that intuitively.  (Well, perhaps people using high-power ND filters to block out that awful light that is ruining their lovely photographs of milky waterfalls and speeding snails may not get it so quickly.  )

Instead, he seems to have decided to roll back to "There is only one possible interpretation for 'equivalence', or you're an idiot!" and try it on the MicroFT forum.

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Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: There is no accepted definition of "equivalent images"

John King wrote:

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

I think that you have said everything that needs to be said about this subject - in a single nutshell.

Simple, succinct, correct.

Well done.

Ooops: http://www.dpreview.com/forums/post/51375949

Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: There is no accepted definition of "equivalent images"

Amin Sabet wrote:

I recently took all my cameras and shot some photos of the same subject from the same distance with them.

These were my settings:

Leica M9 and 35mm lens at f/8, 1/60s, ISO 6400 (2500 pushed 1.3 stops in Lightroom)

Sony NEX-5N and 24mm lens at f/3.2, 1/60s, ISO 1000

Fuji X-E1 and 24mm lens at f/5, 1/60s, ISO 2500

Olympus E-PM2 and 17mm lens at f/4, 1/60s, ISO 1600

I resized all of those to the same diagonal pixel dimension and showed them to a bunch of family and friends, asking the simple question "Which of these images look equivalent to you?"  When pressed to explain what I meant by equivalent, I offered the guidance "Similar in visual properties".

According to Joe's proposed definition of "equivalent images", the Leica, Fuji, and Olympus images were equivalent, and the Sony not equivalent.  Indeed, I could tell that the Sony image had less DOF than the others.  Yet everyone picked the Sony, Fuji, and Oly shots as equivalent, noting that the obvious difference in visual properties was how noisy the Leica image looked.  The second most common observation had to do with slight differences in color rendition.  No one commented on the DOF differences, including my wife who often complains about a photo being blurry when I use a narrow DOF.

To some people, a 35/1.4 on a Leica M9 doesn't produce an image equivalent to one made with a 35/1.4 on a D800.  To this guy, a Canon 35/1.4 on a 5D III doesn't produce an image equivalent to one made with a Sigma 35/1.4 on a D800.

Arguing about what is equivalent is like arguing about what is compact.  There is no accepted definition other than the common use as pertains to focal length equivalents. There is a proposed definition of "equivalent image" but not an accepted one.

Seems like only the "good nerds" qualify for your "acceptance". "Bad nerds" need not apply ?

Amin Sabet, May 13th, 2012, 07:29 AM: http://www.mu-43.com/f102/om-d-e-m5-vs-gh2-dynamic-range-controlled-test-25707/index4.html

pidera Contributing Member • Posts: 903
A good read ... and laugh :)

Oh dear, the reply I posted seems to have gone lost somewhere in the galaxy. No sign of it popping up here. Won't write it all again as I spent too much time already. And certainly there will be more opportunities for this kind of enlightment in the near future !

Cheers

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pidera Contributing Member • Posts: 903
Re: Addendum: Rough, Qualified Approximations Surrounding Settings

When calculating some of the effects you describe, and which I experienced when performing tests using equivalent settings, I once kind of reinvented the bellows factor !

Cheers , P.

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John King
John King Forum Pro • Posts: 14,941
Re: There is no accepted definition of "equivalent images"

Detail Man wrote:

John King wrote:

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

I think that you have said everything that needs to be said about this subject - in a single nutshell.

Simple, succinct, correct.

Well done.

Ooops: http://www.dpreview.com/forums/post/51375949

Yours?
Or mine?

Personally, I think that E2004 got it pretty right.

Defining the "official King James" version of "equivalence" is like trying trying to drive in loose sand. No firm foundation, shifts whether one tries to accelerate, reverse, brake or steer, and eventually ends up with one being bogged in the mire of utter confusion, convolution and complexity; with so many qualifications and "if/buts" and "all other things being equal" (as Cat rightly says, and so have I, the other things are never equal ... ), that it is an endless source of "entertainment" for the one true believer, and a pain in the neck for almost everyone else on this entire forum ...

It is also a paradigm searching for any relevance, IMNSHO.

The ordinary "equivalences" between different formats has been well understood for 100 years or more.
My Rolleiflex 6x6 takes different images from those I take with my 35 mm cameras (of many different brands over the years); different again from 4/3rds, my various phone cameras, my various prosumer cameras, my Minox, the 5x4 I used in my youth.
I do not find these differences surprising; or difficult to understand. I choose the appropriate one for what I want to achieve. And that's just a question of knowing how one's gear works ... RTFM? Good starting point, IMHO.

The VERY LAST thing that I set out to achieve is "equivalent images"!
Sort of completely negates the whole purpose and raison d'etre for having different formats in the first place, if you ask me - and a surprising number of people have, over the years ...

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echelon2004 Veteran Member • Posts: 8,128
Re: There is no accepted definition of "equivalent images"
1

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

Since camera to subject distance ("perspective") is held constant in the comparisons that King James makes, the entire premise of your technical point seems to evaporate into misty dewdrops ...

You can't keep all things unchanged.
--
Anders

'It is nice to be important but it is more important to be nice'

Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: There is no accepted definition of "equivalent images"

echelon2004 wrote:

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

Since camera to subject distance ("perspective") is held constant in the comparisons that King James makes, the entire premise of your technical point seems to evaporate into misty dewdrops ...

You can't keep all things unchanged.

Your SIGINT is coming through heavily encrypted, soldier. Please do expound on your hypothesis.

Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: There is no accepted definition of "equivalent images"

John King wrote:

Detail Man wrote:

John King wrote:

echelon2004 wrote:

Amin Sabet wrote:

There is a proposed definition of "equivalent image" but not an accepted one.

Since perspective is one of the basic parameters in composition together with angle of view and depth of field, equivalence is not possible in any sense that will ever be useful anywhere else but on DPreview. I suppose that could be one of the reasons why only one person has ever bothered trying to come up with a definition

I think that you have said everything that needs to be said about this subject - in a single nutshell.

Simple, succinct, correct.

Well done.

Ooops: http://www.dpreview.com/forums/post/51375949

Yours?
Or mine?

Caution - Bum Steers Crossing ...

pidera Contributing Member • Posts: 903
Re: I agree !

Yes, the resolving power seems to be sensor-limited (nad not lens-limited), especially on the 5d. You can read more on the full test here . In practice it really is quite tricky to match images as much as possible (framing, brightness). Here's another attempt. Using equivalent settings does provide a good starting point though.

Rgds, P.

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Detail Man
Detail Man Forum Pro • Posts: 16,789
Re: A good read ... and laugh :)

pidera wrote:

Oh dear, the reply I posted seems to have gone lost somewhere in the galaxy. No sign of it popping up here. Won't write it all again as I spent too much time already. And certainly there will be more opportunities for this kind of enlightment in the near future !

Sorry to hear about the DPR system core-dump. At least you were nerding-out ! The time-out seems to be somewhere (around) one hour after opening the editor. "That" was our old, obsolete browsers until everybody under the sun reported the same, then it became a bug in the past-tense one week ago (or if, not already vanquished, on that would surely be tamed by the end of last week).

See: http://www.dpreview.com/forums/post/51324484

Lee Jay Forum Pro • Posts: 52,740
Not to crush your spirit....
3

But I'm going to crush your spirit.  Here are two images you would claim are equivalent (same exposure settings).  Do they look equivalent to you?

Now, here are two images taken with the same cameras with "equivalence" applied (same total light captured).  Do these look equivalent to you?

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Detail Man
Detail Man Forum Pro • Posts: 16,789
Correction: Rough, Qualified Approximations Surrounding Settings

Detail Man wrote:

There are certain quantitative characteristics arising out of camera-lens system settings that are measurable (with varying degrees of complexity, for the most part not without aid of instrumentation).

Field of View - Easy to determine (but not as simple as Focal Length when focused at infinity).

Depth of Field - Possible to determine (but varies with any given individual viewers' visual acuity).

Signal/Noise Ratio - Possible to determine (but varies in perceived impact dependent upon the image itself, viewing conditions, and individual viewers, especially where it comes to periodic noise).

.

When we use simplified models that replace complex multi-element lens-systems with single, symmetrical thin lenses, a number of rough approximations are made when scaling settings.

(1) Effective Focal Length should be used instead of the Focal Length when focused at infinity.

(2) Scaling Focal Length as well as the F-Ratio by the ratio of the sensor Crop Factors ignores the fact that the Depth of Field (also) changes as a function of the ratio of the Camera (lens-system front nodal plane) to Subject (plane of focus) Distance to the Hyperfocal Distances involved - by an amount directly proportional to the ratio of the Focal Lengths of compared systems.

My bad, Magister. The Circle or Cornfusion scaling with Sensor Size, all is well. I now recall my once upon a time previously doubting you in surrounding this very issue, and the derivation in your Golden Tablets which showed this illustrious truth was so graciously revealed by you at that time.

Therefore, the inter-format transformations made are only valid when the Camera to Subject Distance is substantially longer than the Focal Length, and are also only valid when the Camera to Subject Distance is substantially shorter than any of the Hyperfocal Distances involved.

It (also) appears that variations due to Effective Focal Length [ EFL = (L) * (1+M/P) ] at close range are also minimal. One thousand apologies for doubting the veracity of your Unified Theory of Everything. I know that I have wandered from The Way, and I humbly ask your forgiveness ...

(3) The relationships of image-noise to sensor size are valid only for Photon Shot Noise when the relative Quantum Efficiencies are known and also factored-in. The additional element, that is ...

... Read Noise (even the entirely random, and not periodic components of), is design-specific in nature, and does appear to reliably follow simplistic assumptions regarding scaling with photosite geometries. Further, the magnitude of (input-referred) Read Noise as well as its (output-referred) proportion (relative to the maximum recorded or recordable peak level) is camera system specific, and is thus a complicated and individualized function of ISO settings.

Therefore, quite a bit of specific actual test-data and knowledge is required in order to meaningfully make such comparisons and assumptions surrounding Signal/Noise Ratio - and such numerical comparisons may not necessarily accurately reflect viewers' subjective perceptions.

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