Panasonic DC-GH6 Sensor Measurements at PhotonsToPhotos

NoSasaeng wrote:

This might be a bit of a stupid question but it says:

"Open symbols indicate values outside the normal analog range"
I've always taken this as like the extended ISO on other cameras. This holds true for the G9 for example. The symbol is closed for ISO 200 and open for any ISO below that since that's the extended ISO. But on the GH6 it is open starting from ISOs below 800, while from my understanding it's ISO 100 and ISO 800 native? So shouldn't ISO 100 to 800 scale kinda similar like 800 to 25600? And the symbol be closed for ISO 100 to 25600?

I wondered about this too. Panasonic defines ISO 50 as the extended low ISO for stills on the GH6: ISO 100 to 800 is part of the native ISO range. Panasonic has not always accurately defined the true native low ISO of their cameras, as can be seen in other PDR charts. However, for Panasonic to define ISOs below 800 (excluding ISO 50) as native ISOs when they're not, just seems bizarre! Perhaps bill could explain what the open symbols mean in this case.

Cafe Racer wrote:

NoSasaeng wrote:

This might be a bit of a stupid question but it says:

"Open symbols indicate values outside the normal analog range"
I've always taken this as like the extended ISO on other cameras. This holds true for the G9 for example. The symbol is closed for ISO 200 and open for any ISO below that since that's the extended ISO. But on the GH6 it is open starting from ISOs below 800, while from my understanding it's ISO 100 and ISO 800 native? So shouldn't ISO 100 to 800 scale kinda similar like 800 to 25600? And the symbol be closed for ISO 100 to 25600?

I wondered about this too. Panasonic defines ISO 50 as the extended low ISO for stills on the GH6: ISO 100 to 800 is part of the native ISO range. Panasonic has not always accurately defined the true native low ISO of their cameras, as can be seen in other PDR charts. However, for Panasonic to define ISOs below 800 (excluding ISO 50) as native ISOs when they're not, just seems bizarre! Perhaps bill could explain what the open symbols mean in this case.

There is no concept of native ISO. A sensor is a light collecting device on board there is also an analog amplifier and an array of digital to analog converters.

The manufacturer will define the minimum gain level that maximize the overall performance according to their criteria. As part of that process they will also look at the exposure and adjust the relationship between gain and gamma corrected middle grey as part of that process (which is why some website like DxOMark talk about how a certain ISO is or not correct).

In this case the camera is optimised to work at its best at the setting that happens to be ISO 800

As the architecture of this sensor is totally different from the previous Sony or Panasonic sensors you cannot draw similarities

Panasonic has only used the word Native for their GH5S which of course was just a dual conversion gain sensor and the defined Native in fact did not even coincide with the switch but mapper other concepts including introduction of noise reduction in video

Interceptor121 wrote:

Cafe Racer wrote:

NoSasaeng wrote:

This might be a bit of a stupid question but it says:

"Open symbols indicate values outside the normal analog range"
I've always taken this as like the extended ISO on other cameras. This holds true for the G9 for example. The symbol is closed for ISO 200 and open for any ISO below that since that's the extended ISO. But on the GH6 it is open starting from ISOs below 800, while from my understanding it's ISO 100 and ISO 800 native? So shouldn't ISO 100 to 800 scale kinda similar like 800 to 25600? And the symbol be closed for ISO 100 to 25600?

I wondered about this too. Panasonic defines ISO 50 as the extended low ISO for stills on the GH6: ISO 100 to 800 is part of the native ISO range. Panasonic has not always accurately defined the true native low ISO of their cameras, as can be seen in other PDR charts. However, for Panasonic to define ISOs below 800 (excluding ISO 50) as native ISOs when they're not, just seems bizarre! Perhaps bill could explain what the open symbols mean in this case.

There is no concept of native ISO. A sensor is a light collecting device on board there is also an analog amplified and an array of digital to analog converters.

The manufacturer will define the minimum gain level that maximize the overall performance according to their criteria. As part of that process they will also look at the exposure and adjust the relationship between gain and gamma corrected middle grey as part of that process (which is why some website like DxOMark talk about how a certain ISO is or not correct).

In this case the camera is optimised to work at its best at the setting that happens to be ISO 800

As the architecture of this sensor is totally different from the previous Sony or Panasonic sensors you cannot draw similarities

Panasonic has only used the word Native for their GH5S which of course was just a dual conversion gain sensor and the defined Native in fact did not even coincide with the switch but mapper other concepts including introduction of noise reduction in video

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

Cafe Racer wrote:

Interceptor121 wrote:

Cafe Racer wrote:

NoSasaeng wrote:

This might be a bit of a stupid question but it says:

"Open symbols indicate values outside the normal analog range"
I've always taken this as like the extended ISO on other cameras. This holds true for the G9 for example. The symbol is closed for ISO 200 and open for any ISO below that since that's the extended ISO. But on the GH6 it is open starting from ISOs below 800, while from my understanding it's ISO 100 and ISO 800 native? So shouldn't ISO 100 to 800 scale kinda similar like 800 to 25600? And the symbol be closed for ISO 100 to 25600?

I wondered about this too. Panasonic defines ISO 50 as the extended low ISO for stills on the GH6: ISO 100 to 800 is part of the native ISO range. Panasonic has not always accurately defined the true native low ISO of their cameras, as can be seen in other PDR charts. However, for Panasonic to define ISOs below 800 (excluding ISO 50) as native ISOs when they're not, just seems bizarre! Perhaps bill could explain what the open symbols mean in this case.

There is no concept of native ISO. A sensor is a light collecting device on board there is also an analog amplified and an array of digital to analog converters.

The manufacturer will define the minimum gain level that maximize the overall performance according to their criteria. As part of that process they will also look at the exposure and adjust the relationship between gain and gamma corrected middle grey as part of that process (which is why some website like DxOMark talk about how a certain ISO is or not correct).

In this case the camera is optimised to work at its best at the setting that happens to be ISO 800

As the architecture of this sensor is totally different from the previous Sony or Panasonic sensors you cannot draw similarities

Panasonic has only used the word Native for their GH5S which of course was just a dual conversion gain sensor and the defined Native in fact did not even coincide with the switch but mapper other concepts including introduction of noise reduction in video

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

That is what the test images say. A quick look at dark frames with any software that can estimate noise shows the issue of read noise.

In practice however you will not see much of that noise if you use those ranges for bright scenes however if you used it for a long exposure at night for example where the scene is mostly darks with few highlights you would see it

There are of course other factors to take into account dynamic range is important but is not the only dimension if you shoot in demanding conditions. Fixed pattern noise (that can be eliminated on a single shot) and black level uniformity are also very important and this camera does not do well on any of those two dimensions. However I took a 128 exposures milky way shots and it turned out quite good!

At present the most reliable camera for landscape photography in the format is the GH5M2, it still has the classic white balance shifts in sunset timelapses but overall is the most uniform camera for both bright and dark scenes and high contrast scenes too

Interceptor121 wrote:

Cafe Racer wrote:

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

That is what the test images say.

That's also what PhotonstoPhotos GH6 PDR chart says.

Cafe Racer wrote:

Interceptor121 wrote:

Cafe Racer wrote:

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

That is what the test images say.

That's also what PhotonstoPhotos GH6 PDR chart says.

I provided the images that make the chart so I guess I know lol

Interceptor121 wrote:

Cafe Racer wrote:

Interceptor121 wrote:

Cafe Racer wrote:

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

That is what the test images say.

That's also what PhotonstoPhotos GH6 PDR chart says.

I provided the images that make the chart so I guess I know lol

Yep.

Cafe Racer wrote:

Interceptor121 wrote:

Cafe Racer wrote:

Interceptor121 wrote:

Cafe Racer wrote:

So essentially we now know that the DR of the GH6 is worse than it's m4/3 peers when shooting still images under ISO 800.

That is what the test images say.

That's also what PhotonstoPhotos GH6 PDR chart says.

I provided the images that make the chart so I guess I know lol

Yep.

If you want to understand more about the inner workings of a camera look at the PTC graphs they show you how despite certain settings seem the same things change wildly between cameras

For example look at the Kadc for a few cameras at ISO 200 you will see significant variation in values even for the same sensor

NoSasaeng wrote:

Funny Valentine wrote:

Pete Berry wrote:

And that reminds me: my almost 5 year old G9 sensor still rules the m4/3 DR roost along with it's use in the more recent GH5-II if you're into the top-dog sensor thing... I do like the larger GH6 stills files, along with the excellent HHHR implementation.

Somehow it seems the GH6 HHHRS doesn't suppress noise like Olympus HHHRS. This needs to be confirmed by someone who owns both.

Also we need to know if the OM-1 HHHRS is as good as E-M1 III HHHRS because they went down to 12 stacked photos from 16. Why would they do this ? if anything, they should've increased the number of stacked photos to increase resolution and noise suppression.

So they can boast about faster processing. HHHR now only takes 7 seconds instead of the 12 seconds in their first iteration.

but is the IQ and noise suppression the same ?

Raist3d wrote:

Funny Valentine wrote:

Pete Berry wrote:

And that reminds me: my almost 5 year old G9 sensor still rules the m4/3 DR roost along with it's use in the more recent GH5-II if you're into the top-dog sensor thing... I do like the larger GH6 stills files, along with the excellent HHHR implementation.

Somehow it seems the GH6 HHHRS doesn't suppress noise like Olympus HHHRS. This needs to be confirmed by someone who owns both.

Also we need to know if the OM-1 HHHRS is as good as E-M1 III HHHRS because they went down to 12 stacked photos from 16. Why would they do this ?

Because due to faster cpu/sensor readout, they can be more confident the number of images they need to create the HHHR are less than the other case, where they may have had to throw away more of the images.

according to Robin Wong and Olympus themselves, in the E-M1 III and X, the HHHRS RAW files were made of 16 stacked photos, for a total of 320 megapixels that were oversampled to 50 mp.

So if the math adds up, the OM-1 must be oversampled from 240 MP only, with 1 stop less DR than the E-M1 X and III.

So in ideal conditions, the old HHHRS should outperform the new HHHRS.

SrMi wrote:

Funny Valentine wrote:

NoSasaeng wrote:

Funny Valentine wrote:

Pete Berry wrote:

And that reminds me: my almost 5 year old G9 sensor still rules the m4/3 DR roost along with it's use in the more recent GH5-II if you're into the top-dog sensor thing... I do like the larger GH6 stills files, along with the excellent HHHR implementation.

Somehow it seems the GH6 HHHRS doesn't suppress noise like Olympus HHHRS. This needs to be confirmed by someone who owns both.

Also we need to know if the OM-1 HHHRS is as good as E-M1 III HHHRS because they went down to 12 stacked photos from 16. Why would they do this ? if anything, they should've increased the number of stacked photos to increase resolution and noise suppression.

So they can boast about faster processing. HHHR now only takes 7 seconds instead of the 12 seconds in their first iteration.

but is the IQ and noise suppression the same ?

It looks the same to me, though we have no measurements.

On the M1x, tripod HR takes only 8 shots and has a very similar PDR to HHHR (16-shots). We do not know how many of those 16 or 12 shots are used by the HHHR algorithm. GH6's HHHR mode picks the best 8 out of 16 shots.

As HHHR invokes IBIS there is a theme of alignment of frames which in HR is not there as it assumes they are aligned (which may ultimately not be true at subpixel level)

I suppose the extra frames are dropped at alignment stage if there is an error detected and not processed

You can work out that a reduced number of shots for example 12 is sufficient to address the most typical alignment issues

At the end of the day I do not think it will make any real difference as according to some theories pixel shift improves IQ but not actual resolution in the end

SrMi wrote:

Funny Valentine wrote:

NoSasaeng wrote:

Funny Valentine wrote:

Pete Berry wrote:

And that reminds me: my almost 5 year old G9 sensor still rules the m4/3 DR roost along with it's use in the more recent GH5-II if you're into the top-dog sensor thing... I do like the larger GH6 stills files, along with the excellent HHHR implementation.

Somehow it seems the GH6 HHHRS doesn't suppress noise like Olympus HHHRS. This needs to be confirmed by someone who owns both.

Also we need to know if the OM-1 HHHRS is as good as E-M1 III HHHRS because they went down to 12 stacked photos from 16. Why would they do this ? if anything, they should've increased the number of stacked photos to increase resolution and noise suppression.

So they can boast about faster processing. HHHR now only takes 7 seconds instead of the 12 seconds in their first iteration.

but is the IQ and noise suppression the same ?

It looks the same to me, though we have no measurements.

On the M1x, tripod HR takes only 8 shots and has a very similar PDR to HHHR (16-shots). We do not know how many of those 16 or 12 shots are used by the HHHR algorithm. GH6's HHHR mode picks the best 8 out of 16 shots.

The OM-1 and probably the E-M1s use 8 of the images. I assume the OM-1 can get the same IQ with fewer images because of the faster readout speed of the sensor and faster frame rates which would reduce the chances of other factors affecting the images.

You can count the number used by looking at an image with something moving (like counting the number of London has fallen in the attached which was scrolling on a TV screen (7 plus the one blank).

I could post an image of a waterfall where you see the many hundreds of droplets 8 times, but I would have to process the image and load it over my slow internet connection.

drj3 wrote:

SrMi wrote:

Funny Valentine wrote:

NoSasaeng wrote:

Funny Valentine wrote:

Pete Berry wrote:

And that reminds me: my almost 5 year old G9 sensor still rules the m4/3 DR roost along with it's use in the more recent GH5-II if you're into the top-dog sensor thing... I do like the larger GH6 stills files, along with the excellent HHHR implementation.

Somehow it seems the GH6 HHHRS doesn't suppress noise like Olympus HHHRS. This needs to be confirmed by someone who owns both.

Also we need to know if the OM-1 HHHRS is as good as E-M1 III HHHRS because they went down to 12 stacked photos from 16. Why would they do this ? if anything, they should've increased the number of stacked photos to increase resolution and noise suppression.

So they can boast about faster processing. HHHR now only takes 7 seconds instead of the 12 seconds in their first iteration.

but is the IQ and noise suppression the same ?

It looks the same to me, though we have no measurements.

On the M1x, tripod HR takes only 8 shots and has a very similar PDR to HHHR (16-shots). We do not know how many of those 16 or 12 shots are used by the HHHR algorithm. GH6's HHHR mode picks the best 8 out of 16 shots.

The OM-1 and probably the E-M1s use 8 of the images. I assume the OM-1 can get the same IQ with fewer images because of the faster readout speed of the sensor and faster frame rates which would reduce the chances of other factors affecting the images.

You can count the number used by looking at an image with something moving (like counting the number of London has fallen in the attached which was scrolling on a TV screen (7 plus the one blank).

I could post an image of a waterfall where you see the many hundreds of droplets 8 times, but I would have to process the image and load it over my slow internet connection.

I think what is likely to happen here is simply that is using the first set of 8 images and then 4 of the 8 for the corners where it is possibly getting most of the issues for a variety of reasons including distortion.

If it has more speed it would not make sense to drop any frames unless they have worked out that some of them do not do much statistically

But as all of this is not clearly explained we will not know

Tim200 wrote:

Simon97 wrote:

I look at the studio scene RAW conversions. Ask yourself if the difference between models is really that drastic. What if you scale the 25mp images down to 20 and compare to the OM-1 or other MFT cameras? Would it make a difference in your photography?

I'd get the GH6 if I had a collection of MFT lenses and wanted to get more into video. Looking at the sample gallery it is a pretty good photo shooter but would lean to the OM-1 for straight photo work.

Yes, the gh6 and om1 look about equal in the studio scene. In fact I think gh6(scaled) actually looks a bit better at higher ISO e.g. 6400. In my use, stills look fine as long as I'm careful with how the shot is exposed. However, what I'm also seeing is the issue outlined in the dpreview article about gh6 low ISO DR. If I have to raise shadows, it quickly becomes noisy. Example I've run into is a subject in front of a bright window. It has taken some practice to get a shot like this which can be processed decently.

This is a reasonable statement and I certainly am not qualified to dispute it.  However, the question for me is compared to what? I have taken test shots like you describe (bright window dark shadows) with both G9 and GH6 with exposure as close as I could get it -1.3 GH6 -1G9 (I think the GH6 meters brighter than the G9, even a third stop wasn't quite enough).  I imported the Raw's to LRC,  zeroed sharpening and NR, brightened  by +2 and exported.  Regarding noise, in every case from ISO100 to 25600 I would take the GH6 files over the G9's.  As far DR, I could not see a difference in my test files, and the G9 is regarded as best in MFT for DR.  Now, was this scientific - hardly.  But it was done as equally as I could within my expertise, and within the parameters of my normal shooting.  For example, I didn't raise anything by 5ev and probably never will.

Now, I expect someone will tell me what I did wrong in testing.  That's cool, but doesn't mean I will understand them or suddenly decide my GH6 is trash.  So far I happen to like the camera.  

Hi Randy:

Test charts are fascinating but real world shooting is what matters in the end.

Have you tested GH6 CAF vs G9?  Curious if any improvements.

Dale

Ranlee wrote:

Tim200 wrote:

Simon97 wrote:

I look at the studio scene RAW conversions. Ask yourself if the difference between models is really that drastic. What if you scale the 25mp images down to 20 and compare to the OM-1 or other MFT cameras? Would it make a difference in your photography?

I'd get the GH6 if I had a collection of MFT lenses and wanted to get more into video. Looking at the sample gallery it is a pretty good photo shooter but would lean to the OM-1 for straight photo work.

Yes, the gh6 and om1 look about equal in the studio scene. In fact I think gh6(scaled) actually looks a bit better at higher ISO e.g. 6400. In my use, stills look fine as long as I'm careful with how the shot is exposed. However, what I'm also seeing is the issue outlined in the dpreview article about gh6 low ISO DR. If I have to raise shadows, it quickly becomes noisy. Example I've run into is a subject in front of a bright window. It has taken some practice to get a shot like this which can be processed decently.

This is a reasonable statement and I certainly am not qualified to dispute it. However, the question for me is compared to what? I have taken test shots like you describe (bright window dark shadows) with both G9 and GH6 with exposure as close as I could get it -1.3 GH6 -1G9 (I think the GH6 meters brighter than the G9, even a third stop wasn't quite enough). I imported the Raw's to LRC, zeroed sharpening and NR, brightened by +2 and exported. Regarding noise, in every case from ISO100 to 25600 I would take the GH6 files over the G9's. As far DR, I could not see a difference in my test files, and the G9 is regarded as best in MFT for DR. Now, was this scientific - hardly. But it was done as equally as I could within my expertise, and within the parameters of my normal shooting. For example, I didn't raise anything by 5ev and probably never will.

Now, I expect someone will tell me what I did wrong in testing. That's cool, but doesn't mean I will understand them or suddenly decide my GH6 is trash. So far I happen to like the camera.