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BMCC problem. Heavy noise at ASA800 and lines across the screen!


Vadim Joy

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Hi, today I set my camera to ASA800, I was told it is a native ASA (best dynamic range + noise performance) I did a quick test and was very surprised. The picture is very noisy and strange lines appear across the screen. I don't think this is due to the bad sensor becasue at ASA200 i don't see the lines and noise is much less visible. I've attached video, please have a look.

I don't know what to do now.

 

http://www.youtube.com/watch?v=aZgADbkykA8

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Well it's nearly impossible to tell off of a low-res youtube clip. However, keep in mind, the camera has no in-camera noise reduction as other systems do, so some noise is there even at 800. And, despite it being an 800asa camera, it doesn't mean you don't need light-- if you are under-exposing and pulling it up you'll see more noise.

 

If there are lines across the footage, I would grab some screen shots off of the original ProRes and/or the RAW and share them with black magic support. They will take care of you if it is a sensor problem. They're really great and turn around as quick as they can. Took care of me on my own pocket camera.

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I see what you're talking about; I get those lines a lot on low-light iPhone snaps and used to see them in files from older, low-res DSLRs. Im not speaking from expertise, but from what I've seen it's just a small-sensor, high sensitivity thing that happens. Are you going for the low contrast, milky-shadow look? You may have to crush the blacks and then reign them in after. I don't own a BMCC, but that looks pretty standard for imaging chips of that size, so I wouldn't worry about anything being wrong with your camera. Just takes a little work in post.

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I've contacted Blackmagic Support and they are looking into it now. I was really surprised how quick they got back to me after I emailed them.

In a meanwhile I'll get out and do few more tests outside in bright light. If it still visible then it's a camera fault, if not then I don't know how to use it properly. Gosh, I really miss my arri sr now. No sensor headache. Just load it and off you go.

I'll post some screenshots later.

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Ha; I know the feeling (as I look at my SR3).

But the thing with digital cameras is that just because they have high ISOs doesn't mean you need no light or can shoot with low-light, necessarily. It just means that you need less powerful lights, though you still want to give a good exposure range across the frame.

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The thing with many digital cameras (and I thought this one) is that they claim to be very clean in low light, but......

I do remember seeing promo footage from the BMPCC shot at 800 iso in mixed conditions and it was very clean, no noise. While it could be your camera, although all your shots look way underexposed, I suspect that said camera isn't as clean in low light as blackmagic would have you believe. Clearly they did loads of post tweaking to their promo footage. I remember all the hype around the c300 during it's pre-release. Canon displayed pristine low light footage showcasing it's abilities in low light. After two seasons on Boston's Finest and 8000 hours of footage (a reality TV record) from the c300, I can personally attest that Canon's claims were marketing spin. We shot tons at night in a police cruiser with the iso at 800 and well beyond and noise was very abundant. It looked much more like grain from say a 500 iso S16 film stock, which by the way, every one loved. So as I look at my Aaton and read your posts, I don't think I will be buying the BMPCC. Maybe rent it as needed but give me those silver salts any day.

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My BMPCC has all sorts of funny lines and noise pieces in it when un-corrected out of the camera. The moment I apply a color correction to it, they completely go away, as if they never existed in the first place. The problem has to do with direct light on the sensor and how it deals with it. For sure one of the "issues" of the camera, but you don't hear people complaining about it because I think most people color correct their material and as a consequence, color-out the issue.

 

I also rate this camera at 200ASA, I find the material looks substantially better at that ISO. I find it delivers far less grain and has a crisper, more cinematic look to it. The camera is a cinema camera, not a camcorder, not an iphone, not a D5MKIII. Its designed to shoot movies and I find just performing simple camera tests to be annoying, the moment you get outside and shoot something, then bring it back for color correction, I think you'll find the camera will work fine.

Edited by Tyler Purcell
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"The camera is a cinema camera, not a camcorder"

 

Please do not smile, that thing will never be a film camera and Red or Alexa, either. They are video cameras that produce nice video but nothing seems real film.

Blackmagic Cinema Camera is a cinema camera. It's not just because it is called "cinema camera". Technically speaking any camera that shoots hd video is a cinema camera today. That's why they invent those 2K, 5K, 100K etc cameras all the time. To be able to make money. But the point is that it's not about the camera, since the camera is only a device that captures images.

 

This might be useful for you http://www.eoshd.com/comments/topic/3461-comparison-alexablackmagicepic/

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"The camera is a cinema camera, not a camcorder"

 

Please do not smile, that thing will never be a film camera and Red or Alexa, either. They are video cameras that produce nice video but nothing seems real film.

Video cameras don't have 13 stops of latitude and RAW recording capabilities. Video camera's don't have "cinema" lens mount options. Video camera's generally shoot highly-compressed video. Video cameras have very few "manual" camera head controls. Most Video cameras are still CCD and not CMOS.

 

Here is a great example of a video camera: http://www.panasonic.com/business/provideo/AJ-PX5000G.asp

 

The blackmagic cinema camera is a good example of a "cinema" camera.

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UPDATE: After speaking with blackamgic support I was told that the camera had an issue with PCB. Replacement PCB was ordered and the camera was then repaired.

Camera is on its way back to me. I will post some DNG screenshots when camera arrives.

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  • 7 months later...

I've had this same problem recently but only when shooting in RAW at 2.5k. at Prores I can't see the lines and have been shooting at 200ASA

The lines are horizontal and very subtle but they mimic the effects of moire, as if the sensor has actually skipped a line of data every so often throughout the vertical measurement of the frame.

I'm sure it would be a simple fix for blackmagic to solve, so think I will send in soon!

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  • 5 months later...

Steve Howe,

 

I don't like helping to dig up dead threads, but I'd just like to say that your comment is not helpful.

 

In my experience, anyone in the photographic arts who works the LA/NYC/London triad know hows how to correctly expose an image on their digital gear. Even if they historically have primarily used 16mm.

 

Vadim Joy posted about experiencing what he thought was a technical quirk; James Oldham noted a similar issue. Blackmagic's customer service responded to Vadim's inquiry, diagnosed the camera with a faulty component, replaced that component, and sent it back to him.

 

Firing off a two-sentence quip is, again, not helpful.

Edited by Max William Lauf
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He posted candle light images as proof of his problem. Candlelight is massively under exposing - of course you're going to get FPN under those conditions. My BMCC gives FPN under those conditions. Manufacturers often replace boards to placate customers.

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Yeah, it looks pretty much like he took a spot reading off the flame. You aren't wrong.

 

But any post that brings up the poor shadow quality in "cinema" cameras is beneficial, I think. And maybe this sort of alchohol-induced control-trollish thing I'm pulling is part of the conversation about that general awareness about how we need deeper and prettier shadows from a camera instead of the more-marketable higher ISOs.

 

Is Blackmagic even reading this?

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'alchohol-induced control-trollish thing'

 

That's a great phrase - will have to remember. :-)

I have to say that I don't find the shadows a problem with the BMCC. You have to expose correctly though. If I'm doing a candle lit scene, I'm still putting a few hundred watts in there and then pulling it down. You still need to sometimes bring out the noise reduction since you often can't control every part of your image. I've got a short at the top of the 'show yer stuff' section and I don't think there's too much noise going on. At least in the original file there aint much. Net compression adds some banding here and there.

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I'll check your stuff out.

 

My video professor used to force everyone in our class to take twice as many lights as we thought we'd need out on location shoots. And he was right. As much as I think the mixed colors of practical lighting are beautiful on video, you need to do a lot of subtle work lighting the background. And that was back with SD tape!

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Just be careful. You lose dynamic range when you shoot under 800asa. Yes, the blacks get cleaner, but you have less highlight detail.

 

This also happens with the c300 (and all of the Canon line).

 

Take a shot of something with clipped highlights at 800asa, and dial your Asa down to 200asa and watch your histogram. Those highlights still remain clipped but are now clipped at 70ire (approx) instead of clipping at 100ire. Careful!

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