Dynamic range difference of sensor operated in FF vs Crop

[Pentaborane]

Hello everyone,
Recently i have been looking through tests and various graphs of sensor tests and these usually come to the conclusion that a FF sensor has higher dynamic range than its APSC counterpart or itself if operated in crop mode.
I understand that aperture crop factor impacts the DOF but not the amount of light hitting a mm^2 of sensor this leads me to a confusion why would 2 sensors made in the same technology like ones found in Sony A7R5 and Sony a6700 that have basically the same pixel pitch and backend electronic processing would create a different DR value.
Especially if according to PhotonsToPixels dynamic range of A7R5 drops when going to APSC but we have the same pixels illuminated with the same amount of light.
This part makes no logical sense, what part of how sensors work am I missing that causes that difference?

 

[A74Me]

The problem i see with your analogy and some others, is we are not measuring/comparing total capacitance are we

Coulombs per volt? No, the significant measurement is total photons captured.

the photo diodes are not connected in series or parallel, they are collecting/storing photons individually are they not ?

Photons aren't stored. The detections are converted to an electrical charge which is stored. While an individual pixel has a FWC and quantifiable SNR, image level noise is determined by the total signal received at the sensor and used to make the image. That's a product of exposure and the light-sensitive medium's surface area. The larger the surface area of a sensor, the greater the total signal at a given exposure and lower the visibility of noise in the image.

i understand what your saying but why keep relating sensor noise to DR ? dynamic range is captured by the individual pixels not the total pixels ?

DR can be measured in individual pixels. DR can be measured at the image level. The former is not nearly as useful for photography.

there will be a slight shift in whats recorded by the individual pixels which is why there is noise ?

sure, but did you see my comparrision normalized image post. Im a anolog multimeter person, ive never liked digital. and my posted image shows that noise is not part of DR

 

[A74Me]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

 

[Ephemeris]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

 

[A74Me]

Most people misconceive what even "pixel-level" DR means, no less image-level DR, which is a function of the pixel-level DR combined with the square root of the number of pixels. Typically, something like 8MP is considered the standard, where an 8MP sensor's DR is the same as the pixel-level DR, and sensors that are less than 8MP have a lower image DR than pixel DR, and sensors that are more than 8MP have more image DR than pixel DR. The pixel-level "noise floor" or lower-delimiter of DR is not some opaque threshold event where every signal that is lower than it is lost, as if it were clipped away by the "noise floor". That is a fictitious model; you can record scenes where 100% white is stops below the noise floor. What you won't have is usable resolution, but you can capture larger shapes, and doing so will reveal the reason that the results are not as good as they could be: the black level is not flat across the sensor; the dynamics of low-frequency and banded readout is not good enough yet for usable imaging below the noise floor. If you had a computer generate the readout noise in a simulation, the computer will not generate low frequency noise greater than is necessary with pure chance, and then any arbitrary low exposure, like ISOs in the millions or tens of millions, can produce a fairly-clean-but-tiny image. "Tiny" doesn't work well, though, with relatively strong low-frequency noise of digital cameras.

thats the whole point, just call it noise, there is no DR loss . if you smoothed out both the crop and the full sensor the DR would be identical. i just did a test with both my a6700 and a7iv shooting both apsc crop and FF sensor the histogram is identical at the ends, there is no measured DR advantage of a lager sensor area. the FF sensor recorded more information in the mid tones shown by the histogram on my computer.

My barometer says that the dew point and temperature are both 29.7. Coincidence?

29.7 inches

Erm Celsius id think.

The coincidence would occur if 100% water saturated.

old barometers were a tube 3 feet long.

Sounds a generalisation. At my school which was a 1700s school ours were all sorts of lengths depending on use case.

My money is on Celcius

A Thomas Page from circa 1750.

to calculate dew point you need 3 variables just like exposure

I'm just suggesting the joke has a link to temperature and temperature and relative humidity is what's needed.

theres actually 4, but we cant measure condensation nuclei density.

he lost me with the post so i was guessing what he was refering to. I like a bit of twisted humor

 

[A74Me]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

 

[A74Me]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

I also refer to good DR sensors as having larger pixels that can record finer voltage readings for smoother mid tone colour graduation, i shoot a lot of fluro coloured costumes for dancers and also print finely graduated grey backdrops and found sensors like the a7iv to be the best i have used over the years. most wil not notice with every day photography ,but shooting studio work it makes a huge difference when PP images. nothing worst than printing posterised greys in the backdrops and then have to revert to the 16 bit files.

 

[Bill Ferris]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point.

Not quite. See below.

so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

A histogram doesn't map dynamic range. It maps the distribution of pixels of different lightnesses. Since all four photos were made of the same scene in the same light using the same exposure, it's expected that their respective histograms would look the same; would have the same lightness.

Dynamic range is a measurement of difference in lightness from black to white in an image. The greater the dynamic range, the more discreet, subtle tonalities one can discern in a photo. It's obvious looking at the above thumbnails that the photo made with the full frame sensor camera shows more subtle gradations in tonality. The incredibly noisy photo made with the bridge camera built around a tiny sensor doesn't show nearly the subtlety in tonal differentiation. The noise in the image makes that impossible.

The bridge camera photo has low dynamic range. The photo made with the full frame camera shows much greater dynamic range.

--
Bill Ferris Photography
Flagstaff, AZ

 

[A74Me]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point.

Not quite. See below.

so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

A histogram doesn't map dynamic range. It maps the distribution of pixels of different lightnesses. Since all four photos were made of the same scene in the same light using the same exposure, it's expected that their respective histograms would look the same; would have the same lightness.

Dynamic range is a measurement of difference in lightness from black to white in an image. The greater the dynamic range, the more discreet, subtle tonalities one can discern in a photo. It's obvious looking at the above thumbnails that the photo made with the full frame sensor camera shows more subtle gradations in tonality. The incredibly noisy photo made with the bridge camera built around a tiny sensor doesn't show nearly the subtlety in tonal differentiation. The noise in the image makes that impossible.

The bridge camera photo has low dynamic range. The photo made with the full frame camera shows much greater dynamic range.

this is the catch. not when viewing the image thumbnail on the computer monitor, the problem is no one is stating at what size of view/print does the noise interfere with tonal graduations ! we all dont print or look at images at 200% view, i do now as im shooting uncropped extreme macro work where i encourge viewers to look at 100 to 200 % to see detail that we never get to view.

 

[Ephemeris]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

So if we have a zero photon situation, what is that lowest recordable voltage generated from? What is it?

 

[JimKasson]

The problem i see with your analogy and some others, is we are not measuring/comparing total capacitance are we

Coulombs per volt? No, the significant measurement is total photons captured.

the photo diodes are not connected in series or parallel, they are collecting/storing photons individually are they not ?

Photons aren't stored. The detections are converted to an electrical charge which is stored. While an individual pixel has a FWC and quantifiable SNR, image level noise is determined by the total signal received at the sensor and used to make the image. That's a product of exposure and the light-sensitive medium's surface area. The larger the surface area of a sensor, the greater the total signal at a given exposure and lower the visibility of noise in the image.

i understand what your saying but why keep relating sensor noise to DR ? dynamic range is captured by the individual pixels not the total pixels ?

DR can be measured in individual pixels. DR can be measured at the image level. The former is not nearly as useful for photography.

there will be a slight shift in whats recorded by the individual pixels which is why there is noise ?

sure, but did you see my comparrision normalized image post. Im a anolog multimeter person, ive never liked digital. and my posted image shows that noise is not part of DR

So you say, but noise and DR are two side of the same coin. DR is full scale over mean signal level at a given SNR. So the noise determines the DR.

--

the last word the last word - Photography meets digital computer technology. Photography wins -- most of the time.

Photography meets digital computer technology. Photography wins -- most of the time.

blog.kasson.com

 

[JimKasson]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

As I said elsewhere, noise and DR are two sides of the came coin.

--

the last word the last word - Photography meets digital computer technology. Photography wins -- most of the time.

Photography meets digital computer technology. Photography wins -- most of the time.

blog.kasson.com

 

[JimKasson]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

Those are two numbers, not one. And they don't tell you how to compute any of the standard DR metrics.

--

the last word the last word - Photography meets digital computer technology. Photography wins -- most of the time.

Photography meets digital computer technology. Photography wins -- most of the time.

blog.kasson.com

 

[A74Me]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

Those are two numbers, not one. And they don't tell you how to compute any of the standard DR metrics.

what are the standardised DR metrics ? this is the part that grey.

 

[JimKasson]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point. so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

You can't measure noise with a histogram, except under special circumstances.

im not im measuring DR

Could you define DR?

the highest and lowest recordable voltage from a single pixel.

Those are two numbers, not one. And they don't tell you how to compute any of the standard DR metrics.

what are the standardised DR metrics ? this is the part that grey.

What is grey here? Here's the answer to your question:

• FS/mean at SNR = 0.
• FS/mean at SNR = 1.
• FS/mean at SNR = 10 for an 8x10 print at 1 foot distance or so.

You need to specify the metric when you talk about DR.

--

the last word the last word - Photography meets digital computer technology. Photography wins -- most of the time.

Photography meets digital computer technology. Photography wins -- most of the time.

blog.kasson.com

 

[Bill Ferris]

Rank the dynamic range in the photos:

https://www.dpreview.com/reviews/im...&x=-0.0029777095272141103&y=0.972631687372969

thanks for the post ,you have just confirmed my point.

Not quite. See below.

so i cropped out the images and viewed them both as thumb nails on my computer and they look the same.

Ive been uusing this method lately as its anolog (what our eyes are seeing projected) not digital where you can zoom, we cant zoom our eyes



DR looks close to me via histogram.

A histogram doesn't map dynamic range. It maps the distribution of pixels of different lightnesses. Since all four photos were made of the same scene in the same light using the same exposure, it's expected that their respective histograms would look the same; would have the same lightness.

Dynamic range is a measurement of difference in lightness from black to white in an image. The greater the dynamic range, the more discreet, subtle tonalities one can discern in a photo. It's obvious looking at the above thumbnails that the photo made with the full frame sensor camera shows more subtle gradations in tonality. The incredibly noisy photo made with the bridge camera built around a tiny sensor doesn't show nearly the subtlety in tonal differentiation. The noise in the image makes that impossible.

The bridge camera photo has low dynamic range. The photo made with the full frame camera shows much greater dynamic range.

this is the catch. not when viewing the image thumbnail on the computer monitor, the problem is no one is stating at what size of view/print does the noise interfere with tonal graduations ! we all dont print or look at images at 200% view, i do now as im shooting uncropped extreme macro work where i encourge viewers to look at 100 to 200 % to see detail that we never get to view.

How the photos are viewed is only relevant to the question of whether or not the difference in dynamic range and noise visibility is discernible. The fact that the larger sensor working with the same exposure will make a photo with greater dynamic range and less visible noise doesn't change just because the viewing experience is setup such that a person doesn't discern the difference.

--
Bill Ferris Photography
Flagstaff, AZ

 

[John Sheehy]

My barometer says that the dew point and temperature are both 29.7. Coincidence?

29.7 inches

So a barometer is not the tool for measuring temperature or measuring dewpoint. Just like a histogram is not the tool for measuring noise or DR.

 

[Mark S Abeln]

The problem i see with your analogy and some others, is we are not measuring/comparing total capacitance are we

Coulombs per volt? No, the significant measurement is total photons captured.

the photo diodes are not connected in series or parallel, they are collecting/storing photons individually are they not ?

Pixels? They collect a large number of photons.

 

[JimKasson]

The problem i see with your analogy and some others, is we are not measuring/comparing total capacitance are we

Coulombs per volt? No, the significant measurement is total photons captured.

the photo diodes are not connected in series or parallel, they are collecting/storing photons individually are they not ?

Pixels? They collect a large number of photons.

The photons don’t survive their encounters with the sensor. I’m sure you know that, but another person seems to be unclear on the subject.

 

[A74Me]

My barometer says that the dew point and temperature are both 29.7. Coincidence?

29.7 inches

So a barometer is not the tool for measuring temperature or measuring dewpoint. Just like a histogram is not the tool for measuring noise or DR.

is that what he ment a barometer can be used to measure dew point

 

[A74Me]

The problem i see with your analogy and some others, is we are not measuring/comparing total capacitance are we

Coulombs per volt? No, the significant measurement is total photons captured.

the photo diodes are not connected in series or parallel, they are collecting/storing photons individually are they not ?

Pixels? They collect a large number of photons.

The photons don’t survive their encounters with the sensor. I’m sure you know that, but another person seems to be unclear on the subject.

the photons are not the actual source of electrical energy recorded that energy comes from the battery.