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Black Magic footage cutting with Alexa

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#1 Andrew Russo

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Posted 16 June 2015 - 11:29 AM

Recently I finished a TV movie on the Alexa original. I have a day of pickups both day exterior and night exterior (available downtown LA light) that is all establishing shots.

 

Right now I'm feeling the heat from producers to shot on a lesser camera. The Black Magic keeps coming up, and I was wondering if anyone has had experience in post with Alexa and Black Magic footage cutting together. Again, I don't need to have the Black Magic cut between actors, just establishing shots/ some mood and texture.

 

What is the best version of the black magic in terms of exposure latitude? 

 

Any tips for in camera settings to get the most versatile images in post?

 

Thanks!

 

-A Russo


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#2 Phil Rhodes

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Posted 16 June 2015 - 11:39 AM

I have never used Blackmagic versus Alexa, but I can say that the original 2.5K Blackmagic Cinema Camera is a rather nice little toy. It has quite severe rolling shutter and you will not wish to shoot violent, fast-moving action, or especially handheld, with it. Otherwise, though, if any low-cost camera will intercut with Alexa, this is it. It reputedly will, quite well.

 

If you need something without the shutter issue, look at the 4K. The dynamic range is nothing like as good, but bear in mind that sizing it down 50% will get you the best part of a stop back in terms of improved noisefloor - underexpose like hell.

 

Avoid the pocket. It's actually good for what it is, but there can be debayering issues in the ProRes and you may wish to avoid the compressed-raw workflow.

 

The original cinema camera, as I say, is absolutely staggeringly good for the money but for that rolling shutter issue.

 

It is also really just a sensor box and a recorder. Depending on what you're shooting, you may wish to spend some time building a package around it to make it easier to handle. It's a sturdy little item inside a reasonably solid metal case and takes reasonably well to having things bolted on.

 

P


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#3 Kenny N Suleimanagich

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Posted 16 June 2015 - 11:54 AM

To speak to Phil's point, I do think the original BMCC is the best option. 

 

The newest firmware in these cameras (like the Pocket and 4K) does have compressed Raw - but it's lossless compression. It just creates .zip files and then algorithmically decompresses them. There is zero loss in quality (I have tested this). 

 

Also, the ProRes debayering was improved on the Pocket recently in a firmware update as well. 

 

I do agree that the rolling shutter can be bad on tighter lenses. Not as bad as the Sony A7S but maybe akin to the 7D. 

 

I shoot documenatary a lot with the BMCC. You will want to watch for overexposure, I personally shoot at 85% zebras in Raw, since there is more headroom. 


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#4 Tyler Purcell

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Posted 16 June 2015 - 12:17 PM

Blackmagic Designs makes several cinema-grade cameras. Some of their first generation cameras like the 2.5k, are less then stellar. However, modern stuff like the Ursa and Ursa Mini 4.6k, are absolutely at the same quality if not better then the Alexa. Obviously the Ursa 4.6k cameras aren't out yet, so you'll probably be using an older one. If that's the case, may I suggest the 4k because even though it does have a few minor issues, it's a far better camera then 2.5k in my opinion. 

 

I've done a lot of mixing Alexa with other cameras, but not the blackmagic's. 


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#5 Kenny N Suleimanagich

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Posted 16 June 2015 - 12:48 PM

For what it's worth, the 2.5K was just used on 'Mad Max: Fury Road' for a variety of fast-moving shots. 


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#6 David Hessel

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Posted 16 June 2015 - 02:11 PM

From what I have seen I would go with the original BMCC 2.5k for sure, although I have never used an Alexa personally but have worked with footage from both. They seem to have similar color science and dynamic range, it also has a nice grainy noise rather than RGB color noise. Of all the current camera's it is still the best in terms of IQ at least until the 4.6K comes out as far as I am concerned. Also it is not the same camera it was even a year ago, there have been many significant firmware updates that have really patched a lot of the holes it had when it was first released. After all it didn't earn the nickname baby Alexa without reason.


Edited by David Hessel, 16 June 2015 - 02:12 PM.

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#7 Nelson Rogers

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Posted 16 June 2015 - 08:53 PM

I have used the Alexa and 4k Blackmagic Production Camera together on a feature.  We shot 4k RAW on the BMPC. I found it stood it's own when we used it on stand alone scenes i.e.: handheld work and INT car stuff. The Alexa was set up with Canon Cinema Zooms and the BMPC had the Canon Cine Primes. I think using matching lenses helped a lot. We did end up using it as a 2nd camera on the same scene cross shooting a dialogue scene at dusk. The Alexa did have way better detail in the shadows, but after the color grade I don't think the general audience will notice. 

 

I also used the BMPC on a few shots on a Ronin for a night EXT scene set in a wheat field for running shots, the rest was on the Alexa. It was lit with an 18k backlight on a lift and 5k's through 8x's on the ground. I was happy with the results. I have also done some testing of just city streets with available light and if you have fast lenses you should be fine. I'd maybe test shooting at 400 ASA and pushing a little bit compared to shooting 800 at night. I find 800 ASA a bit noisy still if not properly exposed.  Also, shoot 4k RAW to get the best image possible. 

For the day stuff, use IR ND's to keep the black detail from getting polluted. 

 

I personally haven't used the 2.5k Blackmagic, so I can't give an insight to it, but the 4k has the global shutter, so you won't have any issues with rolling shutter with the 4k version. 

 

Hope that helps a bit. Just make sure to put some good glass on it, hopefully matching to what you shot on originally. 

 

Good luck. 

 

-Nelson


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