Pocket 4K vertical Banding up to 1000 ISO

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AntonioAlva

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Pocket 4K vertical Banding up to 1000 ISO

PostTue Dec 07, 2021 10:50 pm

Hi,
This is my first time posting in this forum and also the first time owning a Blackmagic Camera.

So far I'm pretty happy with my new camera but there is one thing that bother me, let me be more exhaustive, when shooting in ISO between 100 and 1000, so in the first gain, I get a strange Banding on the images, especially visibile in dark areas and with high ISO below 1250.

It's like the sensor is divided in three areas, one left, one in the middle and one in the right, all areas do have a slight difference in luminance.

If I cross 1250 ISO, these areas disappear.

I would like to know if this is an expected behavior or there is something wrong with my unit.

I mist say it is also visible in the final output in both BRaw and ProRes.

Thank you in advance for the help, here is a test that clearly show the problem, it also affect illuminated area even though at a lesser degree.

https://vimeo.com/654202576/bc5a9fad85
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Peter J. DeCrescenzo

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostWed Dec 08, 2021 5:19 pm

ISO 1000 is very noisy because it's the maximum gain setting within the camera's lower ISO range.

As noted at the bottom of page 52 in the camera's user manual, use ISO 1250 instead of ISO 1000.

PDF:
https://documents.blackmagicdesign.com/ ... 9420411000
My video examples/tests:
https://vimeo.com/user157457723
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Mike Potton

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostWed Dec 08, 2021 5:39 pm

Contact BMD directly and show them your video, thats something more unsusual than just noise.
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rick.lang

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostWed Dec 08, 2021 6:54 pm

Agree with Mike. Contact your retailer or BMD Support to have that repaired or replaced.

You could try to install the latest firmware 7.3 and see if the problem is corrected before you contact BMD.

If you are on 7. 3, you might try an earlier version and then retry 7.3. On the BMD Support webpage you can scroll down the left hand panel to find an earlier version.
Rick Lang
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AntonioAlva

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostThu Dec 09, 2021 12:55 am

Peter J. DeCrescenzo wrote:ISO 1000 is very noisy because it's the maximum gain setting within the camera's lower ISO range.

As noted at the bottom of page 52 in the camera's user manual, use ISO 1250 instead of ISO 1000.

PDF:
https://documents.blackmagicdesign.com/ ... 9420411000


Indeed I am aware of the noise and I'm not to worried about it, what bothers me is the three vertical Banding that only appear at all ISO until 1250, not oly 1000 but also 100, It's just easier to show at ISO 1000

Mike Potton wrote:Contact BMD directly and show them your video, thats something more unsusual than just noise.


I will and hopefully I will update soon the thread, thank you for the advice

rick.lang wrote:Agree with Mike. Contact your retailer or BMD Support to have that repaired or replaced.

You could try to install the latest firmware 7.3 and see if the problem is corrected before you contact BMD.

If you are on 7. 3, you might try an earlier version and then retry 7.3. On the BMD Support webpage you can scroll down the left hand panel to find an earlier version.


I have no Idea if this is software related as it is a brand new camera and already came with version 7.3, I will contact BMD directly and depending on what they say I'll ask the reseller a new one as I just bought it.

thank you guys for the support!
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AntonioAlva

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostThu Dec 09, 2021 9:02 pm

thank you all for your answeres, I already replied but for some reason my comment won't show up..

Peter J. DeCrescenzo wrote:ISO 1000 is very noisy because it's the maximum gain setting within the camera's lower ISO range.

As noted at the bottom of page 52 in the camera's user manual, use ISO 1250 instead of ISO 1000.

PDF:
https://documents.blackmagicdesign.com/ ... 9420411000


I know that and I don't mind the noise, what's bothers me is in fact the vertical banding that show only in that Iso range, not even at 25600.

Also the video is made to make it clear to see but it is also visible, even if at a lesser degree on a more properly lit environment.

Mike Potton wrote:Contact BMD directly and show them your video, thats something more unsusual than just noise.
rick.lang wrote:Agree with Mike. Contact your retailer or BMD Support to have that repaired or replaced.

You could try to install the latest firmware 7.3 and see if the problem is corrected before you contact BMD.

If you are on 7. 3, you might try an earlier version and then retry 7.3. On the BMD Support webpage you can scroll down the left hand panel to find an earlier version.


Thank you, indeed it seems too strange... I already sent an email to Blackmagic, hope they'll answer soon so I may get a new one from the reseller.

What's I really like about raw is the freedom to push a bit more the grading than compressed codecs, but due to the banding it's impossible.

As Rick said I'll try to downgrade my version and see what happens, I really hope it is software related.
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Zweistein

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostSat Dec 11, 2021 1:45 pm

Hi Antonio, I had similar problems: viewtopic.php?f=2&t=131704

In the end, this seems to be rare and nothing can be done technically. I guess underexposure with ISO1000 (or below) seems to be a danger zone, where this can appear. You might need to have to work around this.
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AntonioAlva

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostSat Dec 11, 2021 6:40 pm

Zweistein wrote:Hi Antonio, I had similar problems: viewtopic.php?f=2&t=131704

In the end, this seems to be rare and nothing can be done technically. I guess underexposure with ISO1000 (or below) seems to be a danger zone, where this can appear. You might need to have to work around this.
Thank you, I read your thread and yes, we both have the same problem, do you believe is a rare scenario or a rare probablem that affect few units?
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Zweistein

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostSun Dec 12, 2021 10:38 pm

AntonioAlva wrote:
Zweistein wrote:Hi Antonio, I had similar problems

Thank you, I read your thread and yes, we both have the same problem, do you believe is a rare scenario or a rare probablem that affect few units?


I actually don't know.
But what still makes me wonder is the fact, that I used the same Pocket 4K on a feature film I shot and graded, so I worked with hours of footage over months and months and none of the footage (even that which was shot in similar conditions as the footage where the line appears) had this issue. So I guess this issue came only later, with time.

I still can reproduce that issue. But I also know how to work around: Use the false color to expose for one of the two base ISO values (400/3200). If I then manage not to underexpose, the line won't be visible for me, even with extensive grading.

I recently stumbled upon this: https://www.cined.com/red-v-raptor-can- ... n-footage/
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AntonioAlva

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostSun Dec 12, 2021 11:41 pm

Zweistein wrote:
AntonioAlva wrote:
Zweistein wrote:Hi Antonio, I had similar problems

Thank you, I read your thread and yes, we both have the same problem, do you believe is a rare scenario or a rare probablem that affect few units?


I actually don't know.
But what still makes me wonder is the fact, that I used the same Pocket 4K on a feature film I shot and graded, so I worked with hours of footage over months and months and none of the footage (even that which was shot in similar conditions as the footage where the line appears) had this issue. So I guess this issue came only later, with time.

I still can reproduce that issue. But I also know how to work around: Use the false color to expose for one of the two base ISO values (400/3200). If I then manage not to underexpose, the line won't be visible for me, even with extensive grading.

I recently stumbled upon this: https://www.cined.com/red-v-raptor-can- ... n-footage/
Thank you sharing your experience, excuse me if the reply comes a bit late but my messages are taking a bit to get approved.

I read the article and indeed it seem the same problem, what's strange is that the separation on ours models are not equal, and differently sized sensor stitched together (to create a mft) make less sense to me even thought it seems the case here.

I'm in contact with BMD and also sent them a few scenes they asked to evaluate the sensor, but the condition they require are not prone to reproduce the problem.

I will update this topic as soon as I get an update, meanwhile thank you all and thank you again Zweistein for your suggestions.
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Zweistein

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostMon Dec 13, 2021 12:21 am

You're welcome!
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AntonioAlva

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Re: Pocket 4K vertical Banding up to 1000 ISO

PostTue Dec 14, 2021 11:54 am

Zweistein wrote:
AntonioAlva wrote:
Zweistein wrote:Hi Antonio, I had similar problems

Thank you, I read your thread and yes, we both have the same problem, do you believe is a rare scenario or a rare probablem that affect few units?


I actually don't know.
But what still makes me wonder is the fact, that I used the same Pocket 4K on a feature film I shot and graded, so I worked with hours of footage over months and months and none of the footage (even that which was shot in similar conditions as the footage where the line appears) had this issue. So I guess this issue came only later, with time.

I still can reproduce that issue. But I also know how to work around: Use the false color to expose for one of the two base ISO values (400/3200). If I then manage not to underexpose, the line won't be visible for me, even with extensive grading.

I recently stumbled upon this: https://www.cined.com/red-v-raptor-can- ... n-footage/


I've been reading about the problem, but what's different is that on the pocket does not affect highlights but seems it only shows different noise patterns when a diegetic light is captured in a otherwise underexposed shot, ie. when there's a strong contrast and a lot of shadows.

I'm still waiting infos from BMD

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