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Which 4K camera for the masses? GH4 vs Blackmagic Production Camera


Andrew Reid
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Some very good points in here Tim.

 

Seemingly you're coming at this from the perspective of a professional and you want a broadcast ready 4:2:2 camera. The article wasn't quite aimed at you, more towards the affordable camera / DSLR crowd. That's why I don't mark down the GH4 very harshly for the lack of internal 4:2:2. Most shooters don't give a rats ass about whether their camera is BBC accredited or not. You're right on the placement of the HDMI port though. It's not ideal. Would rather see it on the right and full sized. As for WHY the internal codec lacks 4:2:2 sampling despite it being in the imaging pipeline right up until the final compression stages, it may or may not be a product segmentation issue. I expect Atomos and Convergent Design probably had a large say in it if they've been involved in product feedback with Panasonic. It's absolutely in their interest to see the spec of HDMI come up a bit, because it's been poor so far. It's also in their interests to see internal codecs stay relatively basic. Anyway enough speculation...

 

PL and native MFT lenses on the GH4 I see as an advantage, because neither go on the Blackmagic EF mount. Yes Canon glass is great but you will at some point be able to put it on the GH4 with full electronic functionality.

 

For DR specs I am going off what I am told by Panasonic and Blackmagic plus a visual evaluation of the footage based on my experience with other cameras. You're right, this can't be independantly verified until the cameras ship and are tested. I'd be very surprised if the GH4 doesn't have similar dynamic range to the C300.

 

In a professional setting what lets down the Blackmagic is audio. Sucks!

 

 

Some very good points in here Tim.

 

Seemingly you're coming at this from the perspective of a professional and you want a broadcast ready 4:2:2 camera. The article wasn't quite aimed at you, more towards the affordable camera / DSLR crowd. That's why I don't mark down the GH4 very harshly for the lack of internal 4:2:2. Most shooters don't give a rats ass about whether their camera is BBC accredited or not. You're right on the placement of the HDMI port though. It's not ideal. Would rather see it on the right and full sized. As for WHY the internal codec lacks 4:2:2 sampling despite it being in the imaging pipeline right up until the final compression stages, it may or may not be a product segmentation issue. I expect Atomos and Convergent Design probably had a large say in it if they've been involved in product feedback with Panasonic. It's absolutely in their interest to see the spec of HDMI come up a bit, because it's been poor so far. It's also in their interests to see internal codecs stay relatively basic. Anyway enough speculation...

 

PL and native MFT lenses on the GH4 I see as an advantage, because neither go on the Blackmagic EF mount. Yes Canon glass is great but you will at some point be able to put it on the GH4 with full electronic functionality.

 

For DR specs I am going off what I am told by Panasonic and Blackmagic plus a visual evaluation of the footage based on my experience with other cameras. You're right, this can't be independantly verified until the cameras ship and are tested. I'd be very surprised if the GH4 doesn't have similar dynamic range to the C300.

 

In a professional setting what lets down the Blackmagic is audio. Sucks!

Andrew, thanks for the response. With all due respect, you say that I'm coming from the wrong perspective. When you started talking about  PL mounts, I thought a professional perspective was not out of line. Eitherway, you do have a good point about the limited PL options with EF. But you can get decent cine style glass with EF mount these days. And I agree, all BMC cameras dropped the ball with audio. 

 

Regarding 4:2:2, you're right, most prosumers won't care. I was hoping for pro specs in prosumer clothes. A few on this forum say broadcasters don't care. Perhaps in their experience. I've shot mostly doc, commercial and episodic, no "live at five" news, and at least half the channels (in the US) are quite specific about color sampling standards (with deliverables), some seem not to care at all (VH1, A&E). But if they didn't, I do for the sake of IQ and grading.

 

All that said, I'm hoping the IQ of GH4 is so overwhelmingly good, that it'll get a hall pass. I'm truly on the fence for buying one and if so most likely with a Speedbooster. If you have any inside info about the ISO, what is its threshold before the noise is noticeable? This is one of the specs that prompted me to ditch my Gh3.

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As has been said... you can downscale that 4k 4:2:0 image to pristine 4:4:4 HD.

 

Just shoot 4k, edit 4k and in the end (when you downscale to HD) you will get 4:4:4. After that you can compress it to prores 4:2:2 or anything really.

 

This sounds great in theory. I'm just somewhat confused as to how the downscale renders the same proportions of Luma / Chroma  of 444 if coming from 420. I know the information is there in the 4k. How does it throw out excess Luma samples? I understand certain cameras (C 300, Alexa, F65, etc) oversample in 4k or 8k to achieve high color sampling in 1080/2k. What software can do this with similar results?

 

Barry Green does a good job explaining it in this thread: http://www.bmcuser.com/showthread.php?120-ProRes-4-4-4-possible/page2

 

In theory, the GH4 should be able to yield a higher color sampling in 1080p than the BMCPC.

 

If anyone has more experience with this downconversion/up sampling color space in post, I'd love to hear about recommended workflow. I've dealt with transcoding R3D files, so this extra step isn't a deal breaker. As I never have to deliver 4k files and have no desire to use an external recorder, this makes the GH4 look like a winner. 

 

Anymore insights to this? Thanks.

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Good article on this new camera.  A lot of people in the forum complaining about different things but no camera is perfect.  The Blackmagic cams do 4-2-2 but they do so with a lot of little quirks like internal batteries, no phantom power, and limited frame rates. The GH4 has a bunch of frame rates and some really high bit rates.  I am a big fan of the C100, rented it for some work last year, but it is too expensive for me to own.  This camera sounds like specs wise it will be close to the C100 but lacking in the low light performance of course.  I think for $2,000 it is going to potentially be a great camera. 

 

I am an events/doc shooter mainly so I do not care so much about 4-2-2 because I do not do keying.  If I need it though I could rent the external recorder attachment.  It is nice to know I could get it if I want it but like I said I doubt I will.  I am also a photographer so I like cameras that do both.  It is exciting to have a camera like this that does not have a lot of compromises for video and also lets me do stills well.  Looking forward to hearing more about this camera and some video samples.  Thanks for the information in the article. 

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As has been said... you can downscale that 4k 4:2:0 image to pristine 4:4:4 HD.

 

Just shoot 4k, edit 4k and in the end (when you downscale to HD) you will get 4:4:4. After that you can compress it to prores 4:2:2 or anything really.

Have you done this or anyone else for that matter? Sounds great, someone please explain what software they used to get 422 or better results. Yes, several cameras do this in camera and down sample so it should be possible in software.

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Guest Ebrahim Saadawi

It seems anyone criticises this particular camera is not very welcomed by many :D
It's a great camera, a revolution even for introducing 4k at the price point, is it perfect? No. Some of us need things that it does not do, and some of us only need the things it can do. It's fine. It's how the world works

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Guest Ebrahim Saadawi

On a side note I am very intruiged by the idea of downscaled 4k 8bit 4:2:0 equalling 1080p 10bit 4:4:4. Can someone (Eoshd maybe) elaborate with an article, samples, or so?

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This sounds great in theory. I'm just somewhat confused as to how the downscale renders the same proportions of Luma / Chroma  of 444 if coming from 420. I know the information is there in the 4k. How does it throw out excess Luma samples?

 

The same way as photoshop or any other good scaler works. Just take 4 luma pixels and 1 chroma that completely covers the 4 luma pixels. Downscale to 1 pixels. Now you have one pixel with one luma value.

 

Downscaling an HD 4:2:0 to SD 4:4:4 is exactly the same as is 4k to HD.

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Have you done this or anyone else for that matter? Sounds great, someone please explain what software they used to get 422 or better results. Yes, several cameras do this in camera and down sample so it should be possible in software.

 

I did it for years with HDV. Downscaling 1440x1080 to pristine SD. You get almost 4:4:4 SD from 1440x1080 4:2:0 HD. It's easy to see. Just shoot something in HD that shows the chroma artifacts easily and downscale to SD.

 

I got a better SD image from early HDV consumer cams than great SD cams like the DVX100.

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I did it for years with HDV. Downscaling 1440x1080 to pristine SD. You get almost 4:4:4 SD from 1440x1080 4:2:0 HD. It's easy to see. Just shoot something in HD that shows the chroma artifacts easily and downscale to SD.

 

I got a better SD image from early HDV consumer cams than great SD cams like the DVX100.

 So I would do the downscale on any transcode software (Adobe Media Encoder or Compressor) or would I do it on the timeline of an NLE? Any settings other than the output codec I need to be aware of? 

 

Thanks for the good advice. For someone who delivers almost exclusively in 1080p, the GH4 is looking most attractive.

 

 

 

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Which camera for the masses? 43rumors has new rumors on pricing:

 

http://www.43rumors.com/panasonic-gh4-can-it-do-444-at-1080p/

 

There's a link to a camera shop in Finland which is taking preorders for GH4 body only for 1499 euro (which should be including 24% VAT since prices are almost without exception listed including VAT in Finland).

 

I'd say that's a nice price for 4k for the masses :)

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Apparently, it's recommended that when shooting with the BM4K camera, you keep the ISO around 400ISO. So far it seems to be a really bad performer in low light.

 

For around $1000 less than the MB4K (if the GH4 is $1600 as speculated), the GH4+Speedbooster seems like a much better option. If the claimed "highly improved sensitivity" of the GH4 is true, add another stop given by the speedbooster and this could be a low light contender to the 5dIII.

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