URSA - Vertical Noise Pattern Issue

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Todd White

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URSA - Vertical Noise Pattern Issue

PostSun Feb 01, 2015 5:37 am

I've had my URSA EF for a few months. During that time I shot several live theater performances. During brighter scenes the video looks very good. During darker moments however, I can easily see vertical noise lines in the video. I've read online that this can be a common issue/problem with the URSA (or BMCC 4k). I'm thinking I should return my URSA in the hopes that I'll get a non-defective version but I thought I would come on here first to see if anyone had any thoughts or fixes for this relatively common problem with the URSA.
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Todd White

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Re: URSA - Vertical Noise Pattern Issue

PostMon Feb 02, 2015 4:06 am

I've simply decided to return it. It's unacceptably annoying enough to warrant a replacement. While I have enjoyed Blackmagic products in the past, I also understand this is an issue that is not uncommon. Hopefully my replacement URSA will not suffer from the same defect.
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Deyan Parouchev

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Re: URSA - Vertical Noise Pattern Issue

PostTue Feb 03, 2015 3:49 pm

Hello Todd, I have the same issue with my Ursa too. After talking with BM support, they told me that in the case of low light (specially at 800 ISO) this is a normal behaviour with the actual sensor of the camera. I have also horizontal banding. But I think every cameras will have the same issue, please tell us when you will get the new one if the situation is better ?
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David Corigliano

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Re: URSA - Vertical Noise Pattern Issue

PostTue Feb 03, 2015 6:08 pm

Unfortunately, this is not really a "defect" - it's a character of the sensor in the URSA and Blackmagic Production Camera. The extent to which the FPN shows up varies a bit from camera to camera, so perhaps an exchange will give you a better one, but you will still get it. The sensor is rated for 400 ISO/ASA, so the problem will be more apparent at other iso's. Your best bet is to always shoot at 400, set zebras to 95-100%, avoid severely underexposed areas in your shot (always ETTR), and brighten in post.

Luckily for URSA owners (let's hope) - the sensor is interchangeable, so perhaps in the near future Blackmagic will release a better one.
David Corigliano
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Roberto Tafuro

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Re: URSA - Vertical Noise Pattern Issue

PostTue Feb 03, 2015 11:47 pm

Agree with you David. I think that FPN is in every sensor of the BMPC and the URSA, with some difference (less or more) of course. I'm a BMPC owner and i hope that BM will do some imporvements to this and for hot pixels too. Even a Resolve solution in post will be great.
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Patrick Acum

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Re: URSA - Vertical Noise Pattern Issue

PostWed Feb 04, 2015 2:11 pm

I've had exactly the same issue with mine, a kind of horizontal ghosting off highlights in low light scenes. If you're locked off on sticks, you might not see it but handheld it is apparent. My Ursa is back with them again as the first time they said it was normal for the sensor. After putting up with it for a while, I just don't think its acceptable, even at 400 I can sometimes see it and I don't want to have the worry of getting a call after a shoot.
They said the first time it would be fixed in firmware as they said the bmpc4k didn't have the issue so it wasn't sensor related. FPN is common to both cameras at 800 iso. You can't really think of 800 iso as conventional analogue gain to shoot in low light. The sensor is 400 iso - this sensitivity doesn't change regardless of your camera setting and it may be that lifting it in post is a better option (although why this wouldn't then reveal fpn I don't know?)
800 does seem to work to hold highlights if you're using it to push the DR up the scale and the noise doesn't look bad in daylight.
It seems that any low light scene is a potential minefield, even if your subject is keyed and properly exposed. (although the image on the 10 inch looks much worse than when I review the rushes) It seems to depend on the overall light level of the entire scene but without knowing what that threshold is, it makes me nervous. I ve set it up on say a 24mm with a correctly exposed face in a wide shot and there's banding across the dark background. But if you move to a 50mm and the face is proportionally taking up more of the scene, then the whole image shifts up the histogram and it may be fine. I don't know at what point on the histogram this happens. Equally, you could have a scene where the overall level is low, so faces are under but the background is not black and it can be fine. Again, its to do with a very precise threshold on the histogram - when the cameras on my shoulder I can't see this and am relying on zebras for faces which is where things can go wrong.
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Roberto Tafuro

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Re: URSA - Vertical Noise Pattern Issue

PostThu Feb 05, 2015 7:43 pm

Hi Patrick, if you're talking about an horizontal line like "some kind of reflection"/"ghosting"/"flare" in low light conditions, the BMPC, at least mine and the other one that i use, suffer from the same issue. There was a thread here with some dng that explain this "problem". The one that i have and another one that i use have the same "problem". If you rotate the camera, the stripe goes away. A lot of strange issues with this sensor, but as always, URSA and BMPC are not low light cameras... :)
Really hope that BM techs are working on some improvements for this two cameras (i know that i'm repetitive!). The "you pay for what you get" maybe can work for BMPC, but not for the URSA according to me.
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Andrea Monzini

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Re: URSA - Vertical Noise Pattern Issue

PostFri Feb 06, 2015 12:30 pm

In this video the FPN seems to be barely visible in lowlight with BMPC 4K ( it should be the same Ursa Sensor):



EDIT:
With my BMPC in similar low light conditions ( 10:03 min) the FPN is visible at ISO 400.
It seems there are some cameras with barely visible FPN.
An improved sensor calibration in firmware is welcome, so i would like to see it in next firmware updates.
The good news about URSA is that you will be able to upgrade the sensor.

Anyway if the FPN is not as expected i suggest to contact the support that in my experience works very well.
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Johnny Harris

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Re: URSA - Vertical Noise Pattern Issue

PostMon Feb 23, 2015 6:05 am

I keep reading that this issues was corrected with the new 1.9 update (for the BMPC at least).

Is this not the case with Ursa?

Some tests I've seen online were really scary. I can't post links but you can find them yourself. Shame because IMHO the BM cameras have the most cinematic pic in their class and above. There's even a petition on change dot org (663 signatures no less - i kid you not).

Seems to me that whomever is manufacturing the sensors (I know it's not BM), is doing a very spotty job.

I'm sitting on the sidelines 'till this clears up a bit.
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Johnny Harris

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Re: URSA - Vertical Noise Pattern Issue

PostMon Feb 23, 2015 6:43 pm

Sorry for double posting but I do have a question for BM staff:

1) Is there an official response to this issue? In all the threads I've scoured I haven't been able to find anything substantial. Apologies if I'm blind.

2) I commend BM for being so forward thinking and allowing the sensor to be replaceable. Since the whole problem revolves around the Sensor (something which I understand BM does not make) would it be possible to UPGRADE the sensor? Is this on the radar?

3) What is the Official policy regarding sensor problems? I understand that FNP to some degree is inherent, but it should be minimal and 'treatable' via software at least. As for blown out pixels, unless you're really pushing the camera, that would be unacceptable to me.

I for one would like an option of paying a bit extra for a more dependable sensor if that would minimize FNP and blown out pixels. I find the idea of playing crapshoot until you get a proper sensor camera unsettling.

The reason I'm asking all this stuff is because I'm looking at purchasing 2 BM cameras - 1 Ursa and 1 BM4k.

Thank you.

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