Mandatory Noise Reduction (NR) in Various Pentax Cameras

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bclaff Veteran Member • Posts: 6,959
Mandatory Noise Reduction (NR) in Various Pentax Cameras
25

At PhotonsToPhotos I detect signal processing, usually Noise Reduction (NR), using 2D Fourier Transforms (2D FTs).
This mosaic illustrates the whole stop results for the K-1 II:

The first three stops are mostly random and indicate little or no signal processing; all other higher ISO settings show significant NR.

In viewing the Read Noise the NR causes a drop that looks like Dual Conversion Gain but is not:

Note that the down-triangle symbol indicates NR

You can use the interactive chart to see where other Pentax cameras start NR.

In general Pentax often starts NR at a much lower ISO setting than others.
Here's a comparison with a camera that does have Dual Conversion Gain and then later, at a much higher ISO setting, starts NR.

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

Pentax K-1 II
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Iliah Borg Forum Pro • Posts: 24,369
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
1

bclaff wrote:

At PhotonsToPhotos I detect signal processing, usually Noise Reduction (NR), using 2D Fourier Transforms (2D FTs).
This mosaic illustrates the whole stop results for the K-1 II:

The first three stops are mostly random and indicate little or no signal processing; all other higher ISO settings show significant NR.

In viewing the Read Noise the NR causes a drop that looks like Dual Conversion Gain but is not:

Note that the down-triangle symbol indicates NR

You can use the interactive chart to see where other Pentax cameras start NR.

In general Pentax often starts NR at a much lower ISO setting than others.
Here's a comparison with a camera that does have Dual Conversion Gain and then later, at a much higher ISO setting, starts NR.

Hi Bill,

If you still have K-1 original shots, could you compare the level of banding (first 3 stops, vertical line on FTs) between K-1 and K-1 II?

LensBeginner
LensBeginner Contributing Member • Posts: 572
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

bclaff wrote:

The first three stops

So the pictures go:

first row ISO100÷1'600

second row 3'200÷51'200

third row 102'400÷819'200

is that correct?

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OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

LensBeginner wrote:

bclaff wrote:

The first three stops

So the pictures go:

first row ISO100÷1'600

second row 3'200÷51'200

third row 102'400÷819'200

is that correct?

Yes

LensBeginner
LensBeginner Contributing Member • Posts: 572
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

bclaff wrote:

Yes

TY.

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OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
2

Iliah Borg wrote:

bclaff wrote:

At PhotonsToPhotos I detect signal processing, usually Noise Reduction (NR), using 2D Fourier Transforms (2D FTs).
This mosaic illustrates the whole stop results for the K-1 II:

The first three stops are mostly random and indicate little or no signal processing; all other higher ISO settings show significant NR.

...

If you still have K-1 original shots, could you compare the level of banding (first 3 stops, vertical line on FTs) between K-1 and K-1 II?

Here you go:

K-1 is much cleaner (ISOs are in the same locates as the K-1 II image)

However, I wouldn't interpret the slight vertical line as banding; this could easily be a small gradient accentuated by the FT wrapping.

Regards

Iliah Borg Forum Pro • Posts: 24,369
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
2

bclaff wrote:

Iliah Borg wrote:

bclaff wrote:

At PhotonsToPhotos I detect signal processing, usually Noise Reduction (NR), using 2D Fourier Transforms (2D FTs).
This mosaic illustrates the whole stop results for the K-1 II:

The first three stops are mostly random and indicate little or no signal processing; all other higher ISO settings show significant NR.

...

If you still have K-1 original shots, could you compare the level of banding (first 3 stops, vertical line on FTs) between K-1 and K-1 II?

Here you go:

K-1 is much cleaner (ISOs are in the same locates as the K-1 II image)

However, I wouldn't interpret the slight vertical line as banding; this could easily be a small gradient accentuated by the FT wrapping.

Thank you.

I checked, and small blurring along the vertical line removes it, not to mention the banding is quite visible on green channel for example. My impression is that banding on K-1 II may be more pronounced than on K-1, and that may have caused the need in noise reduction (or, a not very successful attempt to remove banding using optical black).

OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
2

Iliah Borg wrote:

...If you still have K-1 original shots, could you compare the level of banding (first 3 stops, vertical line on FTs) between K-1 and K-1 II?

Here is something from the PhotonsToPhotos Sensor Heatmaps:

Lower "metrics" are better; zero would be perfect. Note that the table columns are sort-able.

Both the visual, and the numbers (highlighted), show an increase in row Fixed Pattern Noise (FPN).
It's unclear whether this measurable difference is photographically relevant.

Regards

OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
1

Here is some preliminary Photographic Dynamic Range (PDR) information:

The K-1 II measurements are worthy of publishing on the site yet but this is substantially how it will look.

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

Prognathous Veteran Member • Posts: 9,131
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

Interesting results, thanks for posting.

Is this something Pentax can fix in firmware update?

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OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
6

Prognathous wrote:

Interesting results, thanks for posting.

Is this something Pentax can fix in firmware update?

I would think so but I suspect they don't think of it as broken.

MightyMike Forum Pro • Posts: 38,280
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
1

So bottom line this for me, We all knew added mandatory NR was coming, how much worse is this than ordinary post processing NR? Where would we see negative effects other than ever so slightly weaker sharpness, contrast and resolution?

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OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
4

MightyMike wrote:

So bottom line this for me, We all knew added mandatory NR was coming, how much worse is this than ordinary post processing NR? Where would we see negative effects other than ever so slightly weaker sharpness, contrast and resolution?

I don't have a good objective measure.

I can say that the 2D Fourier Transforms (2D FTs) show more pronounced processing that is usual.
I suspect this is very aggressive Noise Reduction (NR); that would imply more than usual destruction of detail.

OP bclaff Veteran Member • Posts: 6,959
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
2

bclaff wrote:

MightyMike wrote:

So bottom line this for me, We all knew added mandatory NR was coming, how much worse is this than ordinary post processing NR? Where would we see negative effects other than ever so slightly weaker sharpness, contrast and resolution?

I don't have a good objective measure.

I can say that the 2D Fourier Transforms (2D FTs) show more pronounced processing that is usual.

To support my statement of more pronounced processing here are the 2D FTs for the Nikon D90:

D90 2D FTs whole stops starting at ISO 100

This more subtle loss of randomness with the white center and corners/edges is typical of the Noise Reduction (NR) I tend to see.
The Pentax 2D FTs are as extreme as I have seen.

brett nz
brett nz Regular Member • Posts: 391
Thank you for posting :) NT
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Piotr Krochmal New Member • Posts: 1
Re: Thank you for posting :) NT
3

Thank you for testes. I hoped that AUnit working other way. I that case I spend my money on lenses Shame on you Pentax

barbakane
barbakane Forum Member • Posts: 55
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras
4

All I know, which isn't much, is if I like a shot or not. I'm from the film days so noise, at least for me, goes with the territory, I ain't gonna overthink it. I do however applaud the dedication and effort needed to get to these results.

Ian Stuart Forsyth
Ian Stuart Forsyth Veteran Member • Posts: 3,270
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

bclaff wrote:

At PhotonsToPhotos I detect signal processing, usually Noise Reduction (NR), using 2D Fourier Transforms (2D FTs).
This mosaic illustrates the whole stop results for the K-1 II:

The first three stops are mostly random and indicate little or no signal processing; all other higher ISO settings show significant NR.

In viewing the Read Noise the NR causes a drop that looks like Dual Conversion Gain but is not:

Note that the down-triangle symbol indicates NR

You can use the interactive chart to see where other Pentax cameras start NR.

In general Pentax often starts NR at a much lower ISO setting than others.
Here's a comparison with a camera that does have Dual Conversion Gain and then later, at a much higher ISO setting, starts NR.

Just out of curiosity have you done any testing on ether of KP or the K70 as to whether or not they use Dual Conversion Gain and would this explain some of the improvement to noise we see from both those cameras?

This may explain as to why Pentax has decided to use a heavy handed NR with the K1 and the dated sensor so that it would appear as to keep up with the maybe newer sensors found in the KP-K70. The release dates of the KP and K70 could hint to the performance gain seen is from DCG and not the new chip NR chip found in all 3 cameras.

I would find it odd if the Kp and k70 had DCG that pentax would implement any NR to those raw files and especially bellow iso 1600

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Lage New Member • Posts: 18
Re: Mandatory Noise Reduction (NR) in Various Pentax Cameras

Bill, the K-1, and i assume the K-1 II, have menu options for setting noise reduction for long exposures and high ISO.

What was the settings during your tests?

BR,

Lage

LightBug Senior Member • Posts: 2,303
Noise reduction != loss of detail
3

Signal processing may have been done, but that does not mean it’s a bad thing.  Looking at DPR’s K-1ii review’s scene comparison, focusing on the fine text above center (since we know the review lens was not sharp across frame), I cannot spot any so called loss of detail in K-1ii claimed by DPR at any ISO when comparing against K-1.

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