Blackmagic Forum

I just got my BMCC and after testing it I have a couple of questions:

1) I shot some clips and took the SSD to my Mac. I checked some clips and put the SSD back in to the BMCC. I tried to view the clips in the camera, but the clips I viewed in my Mac were not moving (the audio played ok). Is this because Mac writes preview data of the DNGs to the SSD and messes up the SSD's data structure so BMCC doesn't play them right?

2) The battery was at 75% when I first started the camera. I charged it until it was 100% and after a while I started the camera again it dropped down to 75% after a minute or so. Does the current firmware support battery level indicators more precise than dead/25/50/75/100?

3) Since my Mac's display adapter isn't good enough for Davince Resolve, i tried tinkering with the footage in After Effects and camera raw. The first clip I tried was automatically changing the exposure when exported to H.264. Does the camera raw have some kind of automatic exposure as a default?

1) Not 100% sure about this. Make sure that if you wish to play back raw footage, you have set the camera to record raw - same for ProRes or DNxHD - set them to the record mode you wish to playback. Other than that, I do not know.

2) The batter indicator currently only supports values of 100/75/40/25/10. I have found these values to be inaccurate at best. Generally mine goes from 100 - 25 quickly, but stays at 25-10% for a long time before cutting out.

3) Any exposure data in Raw footage from the BMCC is stored as metadata. Some software packages pick up on this and expose accordingly - others do not. Either way, the data is still there.

Hi there. I'm expecting to get my BMCC in the mail tomorrow. I don't know a lot about video playpack in the BMCC, but I know that there is an issue that if you change the recording frame rate in the BMCC from previously shot video, there will be problems playing back the video(i.e. record a shot at 24p, then change the frame rate over to 30i, and you won't be able to watch the 24p video on your BMCC). It's possible that either you have changed your frame rate, or maybe the camera does it automatically(default setting or something) so that when you put your SSD back in, the frame rates don't match anymore. I don't know exactly how this problem manifests itself, so this may not be what you are experiencing, but I'll throw it out there all the same, couldn't hurt to check.

As for the battery issue, I have heard that there are issues with the accuracy of the battery display. Again, not sure on that issue, but that is a possibility.

As for the color issue with converting to h.264. Raw video files are effectively the equivalent of digital film that needs to be developed, and has absolutely no color profile or any other interpretation applied to it by the camera(or it shouldn't anyway, it's supposed to be raw). It's possible (and in fact probable) that AE is applying some kind of gamma correction or other color interpretation to the footage when it renders out in h.264, a lot of post processing software does this when changing video formats. Someone who knows more about this than me could tell you more, but I'm wondering if H.264 has a native color space to it. Once again, I don't know for certain as I haven't played around with that exact kind of conversion myself, but I did have a gig where I was converting raw RED footage over to EXR frame sequences with RED-CineX and it was automatically applying some kind of interpretation to the footage. I had to go back and re-transcode everything to tiffs.



As a final note, I did a quick google search for "h.264 color space" and came up with multiple results referring to a color shift when rendering out with that codec.

Thank you for the answers!

The battery indicator is what it is and I think I have to live with it. The SSD seems to be working ok in the camera while previewing clips when I don't view them in my Mac's Finder, so I think Mac's Finder does something to those files (I can see they are modified after preview) and that changes the data structure. I kinda understand why BM didn't make the option to delete clips because of disk speeds and data structure integrity. Hoping though for an update to even format the drive.

The third question is still a mystery. I did some tests where I pan/tilt the camera from dark to bright and output that from AE+Camera Raw to H.264 and in some scenes the exposure stays the same and in some scenes it gradually changes the aperture in f-spots. I uploaded an example to Youtube and you can see the "click" in about 4 seconds.

I did a test with Prores and it was ok, so I think Camera Raw picks up the metadata and shifts the exposure as Tom suggested. I'm using CS5 and I heard from some tutorial that you should be using CS5.5 or CS6, maybe this is the case?

Is this an EF or mft model? If EF is the lens you used a manual aperture lens or an electronically controlled aperture?

EF model with Sigma 18-35 f1.8 so eletronically controlled. I can't see any problems while previewing clips on the camera, but the output from AE+Camera Raw baffles me.

Matti Tihveräinen wrote:EF model with Sigma 18-35 f1.8 so eletronically controlled. I can't see any problems while previewing clips on the camera, but the output from AE+Camera Raw baffles me.

so the exposure "pop" from that sample clip only happened while viewing it on your computer?

I'm quite positive about that, even though the LCD on the camera cannot be trusted. I'll do some tests tomorrow with raw and Prores + install Davinci Resolve on my work computer. I like the idea of workflow on AE+Camera Raw because i'm familiar with it, but for friday's coming shoot I think i'll go with Prores if I can't figure this out.

I did some more tests and instead of using Camera Raw, I installed Davinci Resolve which gave my Mac Pro kernel panic. After that Resolve was clipping highlights as blueish color so I had to get Mountain Lion to fix it. And then everything worked like a charm. I immediately fell in love with Davinci Resolve! I outputted some clips in Prores HQ 422 1920x1080 and they had some flickering, but the flickering wasn't always in the same place and sometimes I could play a clip without any flickering. So I think the problem is with H.264 or the preview.