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Archive 2017Sony A9 banding in high-contrast areas
p.4 #1Sony A9 banding in high-contrast areas
MJKoski wrote:
Funny, Lloyd's first example did not have strong backlit object, it still had line pattern. And in the end, if PDAF causes this, then the tech is not ready for prime time. It is completely bonkers that suddenly with Sony product with such artifacts are just fine vs. Canon got bashed for years for "banding" problems which were more like user errors in exposure.
to even compare the two, you either havent shot either or just ludicrous.
Funny, Lloyd's first example did not have strong backlit object, it still had line pattern. And in the end, if PDAF causes this, then the tech is not ready for prime time. It is completely bonkers that suddenly with Sony product with such artifacts are just fine vs. Canon got bashed for years for "banding" problems which were more like user errors in exposure.
to even compare the two, you either havent shot either or just ludicrous.
May 28, 2017 at 10:47 AM
p.4 #2Sony A9 banding in high-contrast areas
Now that provocation went completely south :] I have had used 5D1, 5D2, 1Ds2 and 1Ds3 for long enough. Having used orthochromatic paper/film for the last month and the 3-5 stop dynamic range they give, I realized that there was nothing wrong with any FF Canon IQ. Not even close. But this Sony banding, this can be produced without 3-5EV boost which was required to make old Canons pop.
May 28, 2017 at 12:27 PM
p.4 #3Sony A9 banding in high-contrast areas
MJKoski wrote:
Funny, Lloyd's first example did not have strong backlit object, it still had line pattern.
I can't see any banding in the image Lloyd posted - and I refuse to pay to see the full size version.
MJKoski wrote:
And in the end, if PDAF causes this, then the tech is not ready for prime time. It is completely bonkers that suddenly with Sony product with such artifacts are just fine vs. Canon got bashed for years for "banding" problems which were more like user errors in exposure.
The reason is very simple. Canon shadow banding was noise, which by definition is random, which means in the general case it is impossible to remove. The PDAF pixel banding we're seeing here is not only very rare, but when it does occur it is predictable, affecting predefined rows of pixels and only the blue and one of the two green channels, which all means it should be easy to remove in software.
MJKoski wrote:
Now that provocation went completely south :] I have had used 5D1, 5D2, 1Ds2 and 1Ds3 for long enough. Having used orthochromatic paper/film for the last month and the 3-5 stop dynamic range they give, I realized that there was nothing wrong with any FF Canon IQ. Not even close. But this Sony banding, this can be produced without 3-5EV boost which was required to make old Canons pop.
I shot with Canon cameras for years. The banding was a genuine problem that actually affected my shots. I didn't want to switch systems I really liked the Canon lenses and bodies and switching cost a lot of money, but the problem was real and significantly affecting me. Meanwhile I have yet to see the PDAF pixel banding show up in an actual photo with the A7RII - sure I can produce it easily enough by pointing a flash right down the barrel, but I've yet to see it in an actual image.
So, in summry:
- Canon shadow banding: in all images, impossible to remove
- Sony PDAF pixel banding: only present in a small number of images when shining a light directly down the lens, easy to remove.
That is why this isn't a big deal.
Funny, Lloyd's first example did not have strong backlit object, it still had line pattern.
I can't see any banding in the image Lloyd posted - and I refuse to pay to see the full size version.
MJKoski wrote:
And in the end, if PDAF causes this, then the tech is not ready for prime time. It is completely bonkers that suddenly with Sony product with such artifacts are just fine vs. Canon got bashed for years for "banding" problems which were more like user errors in exposure.
The reason is very simple. Canon shadow banding was noise, which by definition is random, which means in the general case it is impossible to remove. The PDAF pixel banding we're seeing here is not only very rare, but when it does occur it is predictable, affecting predefined rows of pixels and only the blue and one of the two green channels, which all means it should be easy to remove in software.
MJKoski wrote:
Now that provocation went completely south :] I have had used 5D1, 5D2, 1Ds2 and 1Ds3 for long enough. Having used orthochromatic paper/film for the last month and the 3-5 stop dynamic range they give, I realized that there was nothing wrong with any FF Canon IQ. Not even close. But this Sony banding, this can be produced without 3-5EV boost which was required to make old Canons pop.
I shot with Canon cameras for years. The banding was a genuine problem that actually affected my shots. I didn't want to switch systems I really liked the Canon lenses and bodies and switching cost a lot of money, but the problem was real and significantly affecting me. Meanwhile I have yet to see the PDAF pixel banding show up in an actual photo with the A7RII - sure I can produce it easily enough by pointing a flash right down the barrel, but I've yet to see it in an actual image.
So, in summry:
- Canon shadow banding: in all images, impossible to remove
- Sony PDAF pixel banding: only present in a small number of images when shining a light directly down the lens, easy to remove.
That is why this isn't a big deal.
May 28, 2017 at 02:07 PM
p.4 #4Sony A9 banding in high-contrast areas
MJKoski wrote:
It may look like so but is not. I have been able to replicate it with 3 different units. All it takes is extreme contrast and horizontal trail of light from powerful source.
This isn't "banding" in the tradition sense. What you have here is massive overexposure causing charge to overflow on readout, which affects the whole row, causing the observed error in the levels of the other pixels on that row (I'm guessing the CDS is getting screwed up). This isn't unique to Sony, other cameras also do this, CCDs were particularly prone to it (a $40000 PhaseOne IQ180 would likely have been worse in this particular scenario). The sensor converts photons to charge, once you exceed the full well capacity that charge has to go somewhere.
The point is the camera just isn't designed for massive overexposure. If I may say so you seem to be pushing the Sony cameras you've had very hard, be it massive overexposure, or extreme temperatures. It's probably the case that they are not the most suitable cameras for being abused in this way, at the end of the day there's a best tool for every job.
But for everyone else who doesn't overexpose, or fire strobes straight down the lens, or uses the camera in -30c temperatures the cameras produce impeccable image quality.
If you want to do this then the Sonys are not for you, move along. I don't think I'm just speaking for myself when I say that seizing upon and making a huge deal of every tiny flaw in cameras you have no intention on buying is becoming extremely tedious.
It may look like so but is not. I have been able to replicate it with 3 different units. All it takes is extreme contrast and horizontal trail of light from powerful source.
This isn't "banding" in the tradition sense. What you have here is massive overexposure causing charge to overflow on readout, which affects the whole row, causing the observed error in the levels of the other pixels on that row (I'm guessing the CDS is getting screwed up). This isn't unique to Sony, other cameras also do this, CCDs were particularly prone to it (a $40000 PhaseOne IQ180 would likely have been worse in this particular scenario). The sensor converts photons to charge, once you exceed the full well capacity that charge has to go somewhere.
The point is the camera just isn't designed for massive overexposure. If I may say so you seem to be pushing the Sony cameras you've had very hard, be it massive overexposure, or extreme temperatures. It's probably the case that they are not the most suitable cameras for being abused in this way, at the end of the day there's a best tool for every job.
But for everyone else who doesn't overexpose, or fire strobes straight down the lens, or uses the camera in -30c temperatures the cameras produce impeccable image quality.
If you want to do this then the Sonys are not for you, move along. I don't think I'm just speaking for myself when I say that seizing upon and making a huge deal of every tiny flaw in cameras you have no intention on buying is becoming extremely tedious.
May 28, 2017 at 02:19 PM
p.4 #5Sony A9 banding in high-contrast areas
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?
Edited on May 28, 2017 at 04:39 PM · View previous versions
Edited on May 28, 2017 at 04:39 PM · View previous versions
May 28, 2017 at 04:19 PM
p.4 #6Sony A9 banding in high-contrast areas
My point was that with a "modern" digital camera be it Canon, Nikon, Sony or whatever life is easy. Just shoot away. If I can survive with paper negative I can do it with any FF Canon. I do not know yet if I can, but it does not seem totally impossible. DR has been enough for over a decade now with any FF camera. And when it comes to extreme DR requirement, HDR bracketing or blending is still the king. Nikon bodies were never a one-shot wonder for me, not D700, D800E or even D810.
The miracle sensor is still to be seen - one that is able to reset pixels and buffer the converted charge as saturation point is reached. So, real HDR chip. That is one kind of device which will turn heads and I would use such even if a battery gives only one exposure.
And btw, R2 chip has insanely good noise performance @ -30C. It survives easily 8 minutes without LENR.
The miracle sensor is still to be seen - one that is able to reset pixels and buffer the converted charge as saturation point is reached. So, real HDR chip. That is one kind of device which will turn heads and I would use such even if a battery gives only one exposure.
And btw, R2 chip has insanely good noise performance @ -30C. It survives easily 8 minutes without LENR.
May 28, 2017 at 04:21 PM
p.4 #7Sony A9 banding in high-contrast areas
jhinkey wrote:
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is blown our + the rays of the sun start? Is it over a small enough area of the sensor that it wouldn't cause this?
I never noticed it on my A7RII files and I shoot a lot of backlit scenes.
However, I did a quick test today and saw it right away. It's very minimal and only shows at certain conditions.
See here:
https://www.fredmiranda.com/forum/topic/1492373/2#14052754
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is blown our + the rays of the sun start? Is it over a small enough area of the sensor that it wouldn't cause this?
I never noticed it on my A7RII files and I shoot a lot of backlit scenes.
However, I did a quick test today and saw it right away. It's very minimal and only shows at certain conditions.
See here:
https://www.fredmiranda.com/forum/topic/1492373/2#14052754
May 28, 2017 at 04:23 PM
p.4 #8Sony A9 banding in high-contrast areas
MJKoski wrote:
My point was that with a "modern" digital camera be it Canon, Nikon, Sony or whatever life is easy. Just shoot away. If I can survive with paper negative I can do it with any FF Canon. I do not know yet if I can, but it does not seem totally impossible. DR has been enough for over a decade now with any FF camera. And when it comes to extreme DR requirement, HDR bracketing or blending is still the king. Nikon bodies were never a one-shot wonder for me, not D700, D800E or even D810.
The miracle sensor is still...Show more →
-30C!! Wow! I still remember your A7RII torture test (amazing) images.
https://www.fredmiranda.com/forum/viewwinners.php?featuredweek=2016-03-11&FeaturedBoardID=46
My point was that with a "modern" digital camera be it Canon, Nikon, Sony or whatever life is easy. Just shoot away. If I can survive with paper negative I can do it with any FF Canon. I do not know yet if I can, but it does not seem totally impossible. DR has been enough for over a decade now with any FF camera. And when it comes to extreme DR requirement, HDR bracketing or blending is still the king. Nikon bodies were never a one-shot wonder for me, not D700, D800E or even D810.
The miracle sensor is still...Show more →
-30C!! Wow! I still remember your A7RII torture test (amazing) images.
https://www.fredmiranda.com/forum/viewwinners.php?featuredweek=2016-03-11&FeaturedBoardID=46
May 28, 2017 at 04:26 PM
p.4 #9Sony A9 banding in high-contrast areas
Fred Miranda wrote:
I never noticed it on my A7RII files and I shoot a lot of backlit scenes.
However, I did a quick test today and saw it right away. It's very minimal and only shows in backlit lighting conditions.
See here:
https://www.fredmiranda.com/forum/topic/1492373/2#14052754
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.
For example, here is his FPN analysis of the A9, A7rII, and A6000:
A7rII FPN Analysis (stacked images, evenly-illuminated)
A9 FPN Analysis (stacked images, evenly-illuminated)
A6000 FPN Analysis (stacked images, evenly-illuminated)
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is blown our + the rays of the sun start? Is it over a small enough area of the sensor that it wouldn't cause this?However, I did a quick test today and saw it right away. It's very minimal and only shows in backlit lighting conditions.
See here:
https://www.fredmiranda.com/forum/topic/1492373/2#14052754
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.
For example, here is his FPN analysis of the A9, A7rII, and A6000:
A7rII FPN Analysis (stacked images, evenly-illuminated)
A9 FPN Analysis (stacked images, evenly-illuminated)
A6000 FPN Analysis (stacked images, evenly-illuminated)
May 28, 2017 at 04:35 PM
p.4 #10Sony A9 banding in high-contrast areas
jhinkey wrote:
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?
I think it depends on light hitting the sensor from a certain angle.
snapsy wrote:
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.
For example, here is his FPN analysis of the A9, A7rII, and A6000:
We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?
I think it depends on light hitting the sensor from a certain angle.
snapsy wrote:
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.
For example, here is his FPN analysis of the A9, A7rII, and A6000:
We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.
May 28, 2017 at 04:43 PM
p.4 #11Sony A9 banding in high-contrast areas
This is a typical image for me (I took this morning) and I can see no such banding anywhere, even after massive contrast, etc. enhancements.
Seems this occurs when a large central area is over exposed as opposed to just a small portion of the sensor.
Fortunately, I Don't See Any Banding In These Kinds Of Images
Seems this occurs when a large central area is over exposed as opposed to just a small portion of the sensor.
Fortunately, I Don't See Any Banding In These Kinds Of Images
May 28, 2017 at 04:51 PM
p.4 #12Sony A9 banding in high-contrast areas
Matt Grum wrote:
I think it depends on light hitting the sensor from a certain angle.
For example, here is his FPN analysis of the A9, A7rII, and A6000:We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.
So it's just certain lenses . . .
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?snapsy wrote
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.For example, here is his FPN analysis of the A9, A7rII, and A6000:
So it's just certain lenses . . .
May 28, 2017 at 04:52 PM
p.4 #13Sony A9 banding in high-contrast areas
Fred Miranda wrote:
The miracle sensor is still to be seen - one that is able to reset pixels and buffer the converted charge as saturation point is reached. So, real HDR chip. That is one kind of device which will turn heads and I would use such even if a battery gives only one exposure.
And btw, R2 chip has insanely good noise performance @ -30C. It survives easily 8 minutes without LENR.-30C!! Wow! I still remember your A7RII torture test (amazing) images.
https://www.fredmiranda.com/forum/viewwinners.php?featuredweek=2016-03-11&FeaturedBoardID=46
It was exposed to -35C that winter but not on that same trip. At -35C or near R2's back LCD starts to freeze over if exposed to cold for long periods. I remember Gary (or someone else, sorry, do not remember) went even colder with it. Always willing to take new gadgets out at those temps 
This winter Pentax K-1 articulating screen support rod froze and the screen got stuck, also IBIS mechanism got stuck @ maximum sensor shift two times.
MJKoski wrote
My point was that with a "modern" digital camera be it Canon, Nikon, Sony or whatever life is easy. Just shoot away. If I can survive with paper negative I can do it with any FF Canon. I do not know yet if I can, but it does not seem totally impossible. DR has been enough for over a decade now with any FF camera. And when it comes to extreme DR requirement, HDR bracketing or blending is still the king. Nikon bodies were never a one-shot wonder for me, not D700, D800E or even D810.The miracle sensor is still to be seen - one that is able to reset pixels and buffer the converted charge as saturation point is reached. So, real HDR chip. That is one kind of device which will turn heads and I would use such even if a battery gives only one exposure.
And btw, R2 chip has insanely good noise performance @ -30C. It survives easily 8 minutes without LENR.
https://www.fredmiranda.com/forum/viewwinners.php?featuredweek=2016-03-11&FeaturedBoardID=46
It was exposed to -35C that winter but not on that same trip. At -35C or near R2's back LCD starts to freeze over if exposed to cold for long periods. I remember Gary (or someone else, sorry, do not remember) went even colder with it. Always willing to take new gadgets out at those temps This winter Pentax K-1 articulating screen support rod froze and the screen got stuck, also IBIS mechanism got stuck @ maximum sensor shift two times.May 28, 2017 at 05:00 PM
p.4 #14Sony A9 banding in high-contrast areas
Jason Lanier talking about the A9 and Wedding photography
https://youtu.be/xyHsyOhsFSk
https://youtu.be/xyHsyOhsFSk
May 28, 2017 at 07:10 PM
p.4 #15Sony A9 banding in high-contrast areas
jhinkey wrote:
I think it depends on light hitting the sensor from a certain angle.
For example, here is his FPN analysis of the A9, A7rII, and A6000:We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.So it's just certain lenses . . .
I think it's not so much certain lenses but how light hits the sensor and creates flare. Backlit lighting lowering image contrast in certain areas of the frame may introduce pixel banding with Sony PDAF sensors.
Matt Grum wrote
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?snapsy wrote
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.For example, here is his FPN analysis of the A9, A7rII, and A6000:
I think it's not so much certain lenses but how light hits the sensor and creates flare. Backlit lighting lowering image contrast in certain areas of the frame may introduce pixel banding with Sony PDAF sensors.
May 28, 2017 at 07:20 PM
p.4 #16Sony A9 banding in high-contrast areas
Fred Miranda wrote:
I think it depends on light hitting the sensor from a certain angle.
For example, here is his FPN analysis of the A9, A7rII, and A6000:We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.So it's just certain lenses . . .I think it's not so much certain lenses but how light hits the sensor and creates flare. Backlit lighting lowering image contrast in certain areas of the frame may introduce pixel banding with Sony PDAF sensors.
Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
jhinkey wrote
Matt Grum wrote
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?snapsy wrote
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.For example, here is his FPN analysis of the A9, A7rII, and A6000:
Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
May 28, 2017 at 08:59 PM
p.4 #17Sony A9 banding in high-contrast areas
MJKoski wrote:
if PDAF causes this, then the tech is not ready for prime time.
I've had problems with phase detect on DSLRs when photographing strongly backlit subjects, so I guess dedicated PDAF sensors are not ready for prime time either
jhinkey wrote:
Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
Yeah I don't know anything for sure - more experiments are needed - but I'm leaning toward it being optical not electronic, as I've seen images of the sensor where you can see the same pattern.
I think the reason you don't see it in the example you posted is that it is not related to the amount of overexposure, but to the amount of lens flare. As flare is light bouncing around the lens and thus hitting the sensor at different angles to usual. So if I'm right about this it will depend to some extent on the lens.
if PDAF causes this, then the tech is not ready for prime time.
I've had problems with phase detect on DSLRs when photographing strongly backlit subjects, so I guess dedicated PDAF sensors are not ready for prime time either
jhinkey wrote:
Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
Yeah I don't know anything for sure - more experiments are needed - but I'm leaning toward it being optical not electronic, as I've seen images of the sensor where you can see the same pattern.
I think the reason you don't see it in the example you posted is that it is not related to the amount of overexposure, but to the amount of lens flare. As flare is light bouncing around the lens and thus hitting the sensor at different angles to usual. So if I'm right about this it will depend to some extent on the lens.
May 29, 2017 at 11:56 AM
p.4 #18Sony A9 banding in high-contrast areas
jhinkey wrote:
I think it depends on light hitting the sensor from a certain angle.
For example, here is his FPN analysis of the A9, A7rII, and A6000:We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.So it's just certain lenses . . .It's not so much certain lenses but how light hits the sensor. Backlit lighting lowering image contrast in certain areas of the frame may introduce pixel banding with Sony PDAF sensors.Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
The horizontal pattern of the PDAF sensors is present on normally exposed shots, it's just much harder to see. For example, Bill Claff's sample here, which is an evenly-illuminated exposure. What remains to be seen is how much of the visible effect in the blown-out images is related to the electrical properties of the sensor (sensor blooming, CDS issues, etc...) and how much if any is a sensor reflection issue.
Fred Miranda wrote
jhinkey wrote
Matt Grum wrote
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?snapsy wrote
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.For example, here is his FPN analysis of the A9, A7rII, and A6000:
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
The horizontal pattern of the PDAF sensors is present on normally exposed shots, it's just much harder to see. For example, Bill Claff's sample here, which is an evenly-illuminated exposure. What remains to be seen is how much of the visible effect in the blown-out images is related to the electrical properties of the sensor (sensor blooming, CDS issues, etc...) and how much if any is a sensor reflection issue.
May 29, 2017 at 12:03 PM
p.4 #19Sony A9 banding in high-contrast areas
snapsy wrote:
I think it depends on light hitting the sensor from a certain angle.
For example, here is his FPN analysis of the A9, A7rII, and A6000:We need to be careful in distinguishing between regular banding from electrical noise, and bright lines from the PDAF pixels when shooting directly toward a light source. Bills measurements show the former, whereas Fred was talking about the latter.So it's just certain lenses . . .It's not so much certain lenses but how light hits the sensor. Backlit lighting lowering image contrast in certain areas of the frame may introduce pixel banding with Sony PDAF sensors.Some ideas are being thrown about, but it's unclear as to the sensor physics that are producing it.
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?The horizontal pattern of the PDAF sensors is present on normally exposed shots, it's just much harder to see. For example, Bill Claff's sample here, which is an evenly-illuminated exposure. What remains to be seen is how much of the visible effect in the blown-out images is related to the electrical properties of the sensor (sensor blooming, CDS issues, etc...) and how much if any is a sensor reflection issue.
Jim Kasson's spectral analysis shows the periodicity occurring in the PRNU and FPN alike.
jhinkey wrote
Fred Miranda wrote
jhinkey wrote
Matt Grum wrote
jhinkey wrote
So, why don't I see this happening on my A7RII when I put the sun in the frame using a wide angle and the disc of the sun is way blown out (plus the rays of the sun star)? Is it over a small enough area of the sensor that it wouldn't cause this?snapsy wrote
I first thought the A9's banding appeared the same as earlier models as well but based on Bill Claff's FPN measurements it appears the A9 is a bit worse, at least compared to the A7rII.For example, here is his FPN analysis of the A9, A7rII, and A6000:
If the PDAF sensors are being over-loaded by blown out highlights, then it should be independent of how the light hits it. If it's some kind of reflection, then it depends on the how the light hits the sensor and is a function of the lens used. Correct?
Jim Kasson's spectral analysis shows the periodicity occurring in the PRNU and FPN alike.
May 29, 2017 at 01:30 PM
p.4 #20Sony A9 banding in high-contrast areas
Ok. Here is a shot straight into the Arizona sun today near noon, 104f. I do not see banding but I do see the clear circle of the sun.
May 29, 2017 at 03:40 PM