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  • Fixed Pattern Noise (Clarification Needed)

    Hi everyone, I am new to Blackmagic Design products and a new owner of the Ursa Mini 4.6K. I wanted to inquire into Fixed Pattern Noise. It's not something I am familiar with as I've never experienced it with any other cameras I've shot with. I am seeing some FPN at both 800 and 1600 ISO. It does not look like the regular noise I am used to seeing with other cameras I've shot with. For example the Sony FS5 is a fairly noisey camera, but what I am seeing on the Ursa Mini looks like a tiny grid/cross hatch. I am aware that this is not a low light camera, but I've also seen some footage/reviews from other owners who seem to have none at all. When I use noise reduction it creates severe banding like I've never seen before. Worse than banding from an 8Bit camera. Below are some screen shots I took of the monitor so you can see where the exposure is at. Granted the exposure is not as well exposed as a shot during the daytime, it still seems like I shouldn't be getting this type of FPN? What's interesting is it doesn't seem like I see any during daylight shots if I would match the histogram as far as underexposure. It's like during the night even if there are ample street lights it turns into a different camera. Daylight shots are clean as a whistle. Am I supposed to crush it out of the image the same as the digital noise I get from my FS5? I just want to make sure I don't have a bad sensor, $5K for me is not throw away money. Would really appreciate some clarification and understanding.

    https://www.dropbox.com/s/m7b2ddjnby...05548.jpg?dl=0

    https://www.dropbox.com/s/m7b2ddjnby...05548.jpg?dl=0

    https://www.dropbox.com/home/BMD?pre...205815_HDR.jpg

    https://www.dropbox.com/s/m7b2ddjnby...05548.jpg?dl=0
    Attached Files
    IG @directedbymbryo
    www.directedbyembryo.com

  • #2
    I'd like to know this too.

    I've had the camera for a week or so and posted in another thread about FPN. I can see it massively at iso 1600 and even 800 in the shadows, even if the rest of the scene is exposed well. Crushing it out is not what I want to do.

    Edit:

    Here's a reference of what I"m talking about. Just something i grabbed quick to test out what im experiencing.

    https://www.dropbox.com/s/5nwr268sfr...ll012.jpg?dl=0

    Comment


    • #3
      So two quick things....

      1. With BMD cameras, you will have to properly expose and correctly lighting your scene. Just no way around this or you'll get FPN.
      2. As to the cross hatch... there an ongoing post that discuss this here. http://www.bmcuser.com/showthread.ph...ht=cross+hatch

      Comment


      • #4
        Originally posted by EYu View Post
        So two quick things....

        1. With BMD cameras, you will have to properly expose and correctly lighting your scene. Just no way around this or you'll get FPN.
        2. As to the cross hatch... there an ongoing post that discuss this here. http://www.bmcuser.com/showthread.ph...ht=cross+hatch
        Of course, that would go for most cameras but in a lot of cases, I actually want dark scenes. Here, it's just there in the shadows, all the time.

        Comment


        • #5
          Originally posted by tremblingwater View Post
          Of course, that would go for most cameras but in a lot of cases, I actually want dark scenes. Here, it's just there in the shadows, all the time.
          Check out this post for dark scenes...
          http://www.bmcuser.com/showthread.ph...ght=dark+scene

          Comment


          • #6
            Originally posted by EYu View Post
            Check out this post for dark scenes...
            http://www.bmcuser.com/showthread.ph...ght=dark+scene
            Most of those scenes are darker than mine (or what I have tested) so i can only presume my unit is actually a dud.

            Comment


            • #7
              How about posting an actual DNG instead of a cell phone shot of your fold out screen uploaded to dropbox. That's step 1.

              Also did you mean to shoot that shot at 5400k? Just curious.

              Update. Just saw you're comparing the lowlight capability of the FS5 to the Ursa Mini? You might have purchased the wrong camera. These aren't anywhere near one another for that style of shooting.

              Comment


              • #8
                Originally posted by tremblingwater View Post
                I'd like to know this too.

                I've had the camera for a week or so and posted in another thread about FPN. I can see it massively at iso 1600 and even 800 in the shadows, even if the rest of the scene is exposed well. Crushing it out is not what I want to do.

                Edit:

                Here's a reference of what I"m talking about. Just something i grabbed quick to test out what im experiencing.

                https://www.dropbox.com/s/5nwr268sfr...ll012.jpg?dl=0
                Your image doesn't look at that, at least viewed on my phone I can't see any FPN. I'll have to view it on my laptop. I agree with you, at 800 iso in a darker scene shouldn't have a grid pattern over my image. It's very strange. I've honestly never experienced anything like it before.
                IG @directedbymbryo
                www.directedbyembryo.com

                Comment


                • #9
                  Originally posted by EYu View Post
                  So two quick things....

                  1. With BMD cameras, you will have to properly expose and correctly lighting your scene. Just no way around this or you'll get FPN.
                  2. As to the cross hatch... there an ongoing post that discuss this here. http://www.bmcuser.com/showthread.ph...ht=cross+hatch
                  I've read through that thread and it seems like most people are pointing to the issue being in Resolve but I don't use Resolve and am seeing it on my upgraded files when just viewing them off the card through QuickTime or VLC Player.
                  IG @directedbymbryo
                  www.directedbyembryo.com

                  Comment


                  • #10
                    Originally posted by vicharris View Post
                    How about posting an actual DNG instead of a cell phone shot of your fold out screen uploaded to dropbox. That's step 1.

                    Also did you mean to shoot that shot at 5400k? Just curious.

                    Update. Just saw you're comparing the lowlight capability of the FS5 to the Ursa Mini? You might have purchased the wrong camera. These aren't anywhere near one another for that style of shooting.
                    I will definitely post a video file/dng. I was posting the shot of the monitor so you can see where the exposure is on the histogram and the type of scene I was shooting. I did not adjust the Kelvin at all. I was more focused on the exposure.

                    I'm also not comparing the 4.6K against the FS5. I'm aware the FS5 will do better in low light. I was comparing the type of noise I get when underexposing a darker scene. I've never experienced this grid pattern cross hatch type of noise. I own both cameras for that exact reason though. They each have different strengths and weaknesses.
                    IG @directedbymbryo
                    www.directedbyembryo.com

                    Comment


                    • #11
                      On a side note. I'm meeting with Tor at Blackmagic Design office in Burbank to test the camera. Hopefully I can get some insight into my sensor and share the info.
                      IG @directedbymbryo
                      www.directedbyembryo.com

                      Comment


                      • #12
                        Well, you have people speculating off of a cell phone shot of your monitor and judging whats going on. I'm sure you can admit that's a bit silly and pointless. Post some DNGs and we'll go from there. Also in regards to the cross hatch, that's usually a scaling problem and is easily fixed or does not show once the image is processed. We had it on the Pocket for some time and it became a non issue for most.

                        Comment


                        • #13
                          Originally posted by tremblingwater View Post
                          I'd like to know this too.

                          I've had the camera for a week or so and posted in another thread about FPN. I can see it massively at iso 1600 and even 800 in the shadows, even if the rest of the scene is exposed well. Crushing it out is not what I want to do.

                          Edit:

                          Here's a reference of what I"m talking about. Just something i grabbed quick to test out what im experiencing.

                          https://www.dropbox.com/s/5nwr268sfr...ll012.jpg?dl=0
                          Did you already process that jpg and what format did you shoot? It has some massive chroma noise baked into it.

                          Comment


                          • #14
                            Originally posted by vicharris View Post
                            Did you already process that jpg and what format did you shoot? It has some massive chroma noise baked into it.

                            The image is 'graded'. Couple of nodes in resolve, I get the same in premiere using the lumetri colour panel.

                            It was shot in prores with the film gamma. I can see it in the log footage itself and that's the thing, even though the rest of the scene has stuff going on in it.

                            Anything i do just brings it out. I'm not claiming to be an expert in this stuff by any means, i'm still getting to grips with it but from my experience, in theory, it shouldn't be this bad. I'm not even pushing it.

                            Just curious really as I want to be certain and I'm sure others here are more knowledgeable on this.

                            Additionally, if this is any help. Here's another example -

                            log footage:
                            https://www.dropbox.com/s/w7f69rhfbg...ll014.jpg?dl=0

                            'graded':
                            https://www.dropbox.com/s/2bqhmmzsxd...ll013.jpg?dl=0

                            Anything i do just brings noise in the shadows. I've already decreased the blanks losing detail in the shadow but its still very noticable. I know it's hard to judge from a JPEG. In motion it's different.
                            Last edited by tremblingwater; 09-29-2016, 11:02 AM.

                            Comment


                            • #15
                              Originally posted by vicharris View Post
                              Well, you have people speculating off of a cell phone shot of your monitor and judging whats going on. I'm sure you can admit that's a bit silly and pointless. Post some DNGs and we'll go from there. Also in regards to the cross hatch, that's usually a scaling problem and is easily fixed or does not show once the image is processed. We had it on the Pocket for some time and it became a non issue for most.
                              I don't think it's silly. I am asking so I can learn and get a better understanding. I used that so you can see where the histogram is in hopes that maybe people will see where my exposure was. Its obviously to the far left. Considering that maybe there's no way around it if it's exposed that far left. Again I don't know and I am asking to learn.
                              IG @directedbymbryo
                              www.directedbyembryo.com

                              Comment

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