BMMCC 4.7 stuck pixels

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Ryan Payne

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BMMCC 4.7 stuck pixels

PostThu Nov 16, 2017 4:37 am

Hey, After Shijan of BMCUSER mentioned he could see some strange pixels after updating to 4.7 for the BMMCC that he could not see on the previous version I decided to check my own.

I can confirm that I am seeing the same odd pixels. They move with the sensor not the image. Also 4.7 has not fixed the cross hatching and need to pixel shift pan and tilt by 0.5 in resolve.

I am not sure if mine were present before 4.7

Shot in RAW 25p. Gave it a good blow out before testing, these aren't caused by something on the ir glass.

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Dmitry Shijan

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Re: BMMCC 4.7 stuck pixels

PostThu Nov 16, 2017 9:34 am

Here are my samples. Fixed dots all around the sensor after 4.7 BMMCC update. I checked old footage and there are no any dots before.

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Dmitry Shijan

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Re: BMMCC 4.7 stuck pixels

PostThu Nov 16, 2017 10:11 am

And i can confirm now that this is not a sensor dust. It is odd bug in firmware 4.7.
Here is link to RAW samples shoot with different firmware and different shutter angles: https://www.dropbox.com/s/ivmas61n2dk9s ... t.zip?dl=0

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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostThu Nov 16, 2017 11:37 am

Thanks for the update Shijan. It's good to know it wasn't there in the previous firmware.

Everyone with a BMMCC on v4.7 I urge you to check your sensor and report back with your results. Let's see if this is an issue for every single unit.
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostFri Nov 17, 2017 12:19 am

Is there a possibility that someone from BMD could check their in house units and see if this is also occurring for them on the 4.7 firmware?

Also if another firmware update is pushed through to correct the issue, some valuable additions would be to correct the crosshatching in davinci resolve. You can see the effect happening in my sample pictures when shooting RAW. It's tedious to have to shift the pan and tilt by 0.5 for every clip.

Another addition would be to have the recording codec shown over the hdmi display. Unlike the pocket camera this is not a feature. It'd really help to reassure the user of their codec. Especially since you can now change codec via sbus, with no visual feedback as to what the camera is recording in this could get dangerous with accidental button presses.

Toggle peaking and zebras via sbus would also be extremely valuable.

Thank you for the continued updates.
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Denny Smith

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Re: BMMCC 4.7 stuck pixels

PostFri Nov 17, 2017 1:52 am

Ryan, the recording frame rate and resolution setting is on the top left corner of the monitor on both the Video Assist and SmallHD monitors, which show the receiving resolution frame rate of the signal, so it is. It necessary to have the camera place this in the bottom camera settings line. The Pocket Camera shows this on its monitor, as it has a built in monitor, the Micro camera lacking a monitor, uses the attached monitor status line to get this frame rate / resolution setting info displayed.

Camera firmware is not going to correct a Resolve display issue, I think you need to do that in Resolve’s firmware. :roll:

Toggling Focus peaking and Zebras would be nice, especially the Zebra. Since the Micro uses an external monitor, I use the monitor’s peaking settings and turn this off in the camera, so I can get a clean screen very quickly. However, I do use camera Zebras to accurately get overexposure/clipping info, so toggling this with SBus would be handy. 8-)
Cheers
Last edited by Denny Smith on Fri Nov 17, 2017 5:51 am, edited 1 time in total.
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostFri Nov 17, 2017 4:07 am

Thank you for the response Denny. I know that the frame rate is already displayed and have no issue with that nor did I mention it as an issue. Further on the small hd dp4 the frame rate is actually in the bottom left corner and I don't believe the resolution is displayed as the BMMCC only records in HD.

You are misinformed for the codec as firmware 4.7 added the ability to change codec via sbus. For my unit using the smallhd dp4 the codec is not displayed on screen. I think this is a basic feature that is avaliable on every other BM camera. The micro should have it and make it a toggle, if you don't want clutter simply turn it off. I do find this an issue or inconvenience. This is further a problem now that you can create a remote that changes the codec and potentially change it accidentally.

But the main issue at hand is of course the stuck pixels.

Thank you.
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Denny Smith

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Re: BMMCC 4.7 stuck pixels

PostFri Nov 17, 2017 5:48 am

Ryan, you are completely correct, my apologies, I missed the bit where codec can be changed via SBus, which would require a display to know what it is. I haven’t applied it to my camera yet, as I am waiting to get some before footage before doing so, after some reports of pixel issues. Thanks for the correction. My SmallHD 501displays frame rate and resolution (yes the Micro Cinema is 1080 only, but the display shows 29.97 1080p in the upper right hand corner, as does the Video Assist. Other monitors like the DP4 may display it elsewhere of course.
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Kristian Lam

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Re: BMMCC 4.7 stuck pixels

PostSat Nov 18, 2017 12:58 am

Hi,

We're looking into report of the stuck pixels after the v4.7 update and have a fair idea of what's going on. We'll update in the next few days to the progress of the fix.
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostSat Nov 18, 2017 1:29 am

Awesome thank you very much Kristian!
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Denny Smith

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Re: BMMCC 4.7 stuck pixels

PostSat Nov 18, 2017 5:37 am

Yes, thanks for taking fast action. I think I will hold off on updating my camera until,you report back.
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Denny Smith
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Tommaso Alvisi

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Re: BMMCC 4.7 stuck pixels

PostSat Nov 18, 2017 10:18 am

Kristian Lam wrote:Hi,

We're looking into report of the stuck pixels after the v4.7 update and have a fair idea of what's going on. We'll update in the next few days to the progress of the fix.


Thanks Kristian!

Please could you guys enable a black shading calibration on the Micro from the menu like you did on the Ursa Mini?

Thanks!
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Kristian Lam

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 12:39 am

Tommaso Alvisi wrote:Thanks Kristian!

Please could you guys enable a black shading calibration on the Micro from the menu like you did on the Ursa Mini?


Why do you need black shading calibration?
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Dmitry Shijan

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 12:46 am

Probably it may help to remove Fixed Pattern Noise and this allow to recover more information from shadows and extend dynamic range. Currently Fixed Pattern Noise can be removed only in pots by substracting Fixed Pattern Mask layer as described in this thread viewtopic.php?f=2&t=19422 Due different cooling systems Fixed Pattern Noise in Micro Cinema Camera is more visible than in Pocket Cinema Camera.

You can see some workarounds about extending dynamic range here viewtopic.php?f=21&t=65149
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CaptainHook

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 3:05 am

Black shading does not target FPN in the URSA Mini 4.6K (Pro). It's purpose is to minimize black balance/offset drift for the 4.6K sensor.
https://vimeo.com/acoupleofnightowls/
http://www.captainhook.co.nz/blackmagic-cinema-camera-lut/

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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 3:42 am

CaptainHook wrote:Black shading does not target FPN in the URSA Mini 4.6K (Pro). It's purpose is to minimize black balance/offset drift for the 4.6K sensor.


Ah interesting, how would FPN be targeted?

My assumption is that the difficulty lay in not also reducing the cameras dynamic range but I'd have no idea how it'd be done.

A question a lot of us have is why the pocket seems to have none and the micro seems to be so affected? I've heard some people say it's the cooling system, some say that it's the left over circuitry from trying to make it global shutter. Really interesting stuff.

Is it something that can realistically be fixed in firmware while keeping acceptable IQ?

Thanks for the replies!
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Stu Aitken

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 3:47 am

CaptainHook wrote:Black shading does not target FPN in the URSA Mini 4.6K (Pro). It's purpose is to minimize black balance/offset drift for the 4.6K sensor.


I think black shading = 'magically fix sensor issues" for many people - probably cos they don't really have any significant comprehension about what it actually does :) (me included)

I'm guessing here but I'm thinking the stuck pixels thing is maybe because some sort of fix for bad pixels on the sensor which has been active in previous firmware maybe went missing this time? (ie its not making bad pixels it's more a case of not hiding them like it used to)
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Tommaso Alvisi

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Re: BMMCC 4.7 stuck pixels

PostMon Nov 20, 2017 4:32 pm

Kristian Lam wrote:
Tommaso Alvisi wrote:Why do you need black shading calibration?


to mask stuck or "dancing" pixels...
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Xtreemtec

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Re: BMMCC 4.7 stuck pixels

PostTue Nov 21, 2017 3:20 pm

I wonder if it would be possible to let the camera's "fix" stuck pixels on it's own. Like JVC, Sony and others do!!

Offcoarse you can fix the Stuck pixels now with Resolve.
But for live video you are still in trouble if you have a stuck or hot pixel in your camera. :roll:

This is a major issue why i don't spend money on a few ursa pro's for live video as i'm afraid i will run into trouble within a few months with several stuck pixels in a set of 6 cameras. (Yes 6 cameras. We run a 4K OBV and want to have 6 cameras with that OBV! )
Daniel Wittenaar .:: Xtreemtec Media Productions ::. -= www.xtreemtec.nl =-
4K OBV, ATEM TVS HD, Production Studio 4K, 2M/E Broadcast Studio 4K, Hyperdeck Studio, SONY FS7 4K, JVC HM700 Full HD Camera
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Kristian Lam

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Re: BMMCC 4.7 stuck pixels

PostWed Nov 22, 2017 3:38 am

Camera v4.7.1 is now and available from our website.
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Denny Smith

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Re: BMMCC 4.7 stuck pixels

PostWed Nov 22, 2017 6:08 am

Thanks Kristian, will down load it now.
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Denny Smith
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostWed Nov 22, 2017 10:53 am

Thanks for the speedy fix, I'll test it out tomorrow and post an update on my end.
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Tommaso Alvisi

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Re: BMMCC 4.7 stuck pixels

PostWed Nov 22, 2017 12:41 pm

Kristian Lam wrote:Camera v4.7.1 is now and available from our website.


Thanks Kristian!
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostWed Nov 22, 2017 11:39 pm

Seems pretty solid. I intentionally went handheld to see if anything was moving with the micro shake. all the splotchy looking stuck pixels seem to be gone from what I can tell.

The only thing of note was that I did find one or two pink pixels but it only for a second or so. it seems to be caused by the drastic change in colours going from brown/gold to black. So I assume there is a stuck pixel there and the fix for it is working to cover it up but me constantly moving it in and out of the black letter is giving it a hard time.

Image

Otherwise it would seem it's fixed, nothing I or anyone would notice shown at normal viewing but I would be interested to test out a macro lens and see what happens, too bad I don't have one :(

Other things are.
-Please put the codec on the display in the top left corner with the ability to toggle it off for those using the video assist.
-cross hatching is still present.

Look forward to see other people do better tests than mine to see if it's fixed or not.

Thank you!
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Dmitry Shijan

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Re: BMMCC 4.7 stuck pixels

PostThu Nov 23, 2017 4:21 am

Ryan Payne wrote:-cross hatching is still present.


Just use this Power Grade node to fix it https://ursa-mini-fpn-grid-pattern-nois ... 18/fix-46k
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Ryan Payne

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Re: BMMCC 4.7 stuck pixels

PostThu Nov 23, 2017 6:38 am

Dmitry Shijan wrote:
Ryan Payne wrote:-cross hatching is still present.


Just use this Power Grade node to fix it https://ursa-mini-fpn-grid-pattern-nois ... 18/fix-46k


Still this shouldn't be a necessary step.

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