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Andrew Reid

Panasonic GH4 in a professional setting - FAQ

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I haven't tried the GH4 yet, but two points you may take into consideration;

 

1. I think you can get a speedbooster for your Contax Zeiss lenses. If you do, it makes the crop factor much closer, and the added light sensitivity will likely make up for most of the advantage a larger sensor would have with the same lenses.

 

2. By downsizing 4K signal to 1080p in post, theoretically it should boost the picture to something like 10bit 422 or better and I would expect it would hold up very well in grading.

 

I was wondering. I'm considering buying either a 5D mark III for RAW or a GH4. Both have their ups a downs, but both of them (as far as I've been able to see) produce stunning images. Sensor size is kind of a biggie for me though.

 

I've put the ups and downs for me here:

 

I own Contax Zeiss lenses, which are 35mm. Full frame ftw. (+1 for 5D)

I already own a Sandisk 64gb extreme pro card, which I can use with the GH4. (+1 for GH4)

GH4 is much cheaper (+1 for GH4)

Recording modes (+1 GH4)

Rolling shutter (I'm guessing +1 GH4)

Noise (I'm guessing 5D still beats the GH4 here?)

External Add on with XLR and SDI (+1 GH4)

Magic Lantern (+1 5D)

 

Here are my concerns really, can anyone tell me how the 5D's RAW holds up against 4K H264? As far as I can see, both look great... on the internet that is.

 

Cheers

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As I understand it, the resolution doesn't matter - 4k/1080p, 24p/30p/60p, whatever; 100Mbps is 100Mbps.

The formula is ((Card Size in GB)*953.7*8)/(3600*(Selected bitrate in megabits per second)). This gives recording time in hours, and assumes that SD cards, like hard drives, are not listed in proper gigabytes. I've never bothered looking into that one.

 

64GB card at 100Mbps is then 1.36 hours of recording time.

 

edit: corrected formula to account for camera bit rates actually being in multiples of 1024 and not 1000.

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As I understand it, the resolution doesn't matter - 4k/1080p, 24p/30p/60p, whatever; 100Mbps is 100Mbps.

The formula is ((Card Size in GB)*953.7*8)/(3600*(Selected bitrate in megabits per second)). This gives recording time in hours, and assumes that SD cards, like hard drives, are not listed in proper gigabytes. I've never bothered looking into that one.

 

64GB card at 100Mbps is then 1.36 hours of recording time.

 

edit: corrected formula to account for camera bit rates actually being in multiples of 1024 and not 1000.

 

Thanks. After using the G6 for the past few months I'v got used to very compressed footage. So was keen to know how much data my exciting SD cards & external storage would hold with the GH4. Think I may need to invest in more external storage if I get one of these monsters. Thunderbolt and solid state I think £££.

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OK imagine it as a highway...

 

5D raw opens up the highway to 6 lanes but there's not really that much traffic, most people stay at home. That's 1080p.

 

GH4 also opens up the highway to 6 lanes but the lanes are busier. Loads of bastards on the road, some of them annoying and noisy. But wow it's a nice busy road :)

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To be honest, I'm having a pretty difficult time interpreting your metaphor... But if I understand correctly, you're saying 1080p is a bit on the way out? Otherwise you may need to provide me with a new metaphor :P

 

I'm worried that the 4K footage will show compression artefacts, even if it's shot at 100mbps.  

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I'm sure you will see good comparisons soon. An alternative is also checking out the 200mbps for 1080p. I am pretty confident that will look great and edit easily.

Also, keep in mind that relatively speaking, the more content you compress, the better it compresses. This goes for both higher resolution and for increased framerates. Try to compress a small picture with jpeg and it doesn't work well. A high rez picture however compresses much better.

 

To be honest, I'm having a pretty difficult time interpreting your metaphor... But if I understand correctly, you're saying 1080p is a bit on the way out? Otherwise you may need to provide me with a new metaphor :P

 

I'm worried that the 4K footage will show compression artefacts, even if it's shot at 100mbps.  

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This may have already been answered but if you buy a PAL GH3 in Australia, there is no record time limit when shooting MOV (Haven't tried the other formats yet).

 

I would assume the GH4 is the same.

 

Still no answer as to the info disappearing after 10-15 seconds. This is a big problem with the GH3.

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Just been doing more research and finding yet more conflicting information regarding the 10 bit 4:2:2 with a recorder, such as the new Ninja Blade from Atomos. 

 

I'm aware of this downsampling thing and its a bit up in the air, but I'm more interested in getting this in ProRes on a recorder. 

 

1. Some sources I've read say that the image can only be played back in 10 bit 4:2:2?

 

2. Some sources say you can record in 10 bit 4:4:2 to an external recorder but this isn't true 10 bit 4:2:2? 

 

3. Many sources say exactly what this site says, that the TRUE 10 bit 4:2:2 can indeed be recorded straight to the external!

 

 

I would say 3 is correct from what I've read on different sites, but just want to have this ABSOLUTELY confirmed (so I know where to put my pennies.)

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Hi again Andrew and everyone else!

 

It appears that the Panasonic GH4 can now output 4K 4:2:2 10-bit to an external recorder through the onboard micro-HDMI port! :)

 

In February I posted a screenshot and a link to the GH4 spec sheet in a thread here on EOSHD, which pretty clearly seemed to state that you can only record 1080p through the onboard HDMI: '?do=embed' frameborder='0' data-embedContent>>

 

Recently, I've seen rumors floating around the web stating that people with hands-on experience with the GH4 now claim that 4K 4:2:2 10-bit is indeed available for external recorders through the onboard HDMI.

 

And now, in this Zacuto video, Panasonic representative, Matt Frazer, clearly states that contrary to some beliefs the GH4 can indeed output 4K 4:2:2 10-bit through the onboard HDMI. Now that is one belief I would be glad to let go!  :)  He goes on to say that he doesn't want people on low budget productions to think they need to spend 1700 USD on the GH4 and 2000 USD on the YAGH to get 4K 4:2:2 10-bit out. Amazing! I really hope this is true, and I find it hard to believe that he would say something like that without being absolutely sure. Perhaps Panasonic changed their mind?

 

Information on the onboard HDMI starts around 9:40 minutes:

 

 

Oh, I've just seen that users "etinoda" and "hoodlum" already posted the link to the Zacuto video in this thread: >

 

 

 

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