Press Release: Panasonic Announces 4K Mirrorless DMC-GH4

[Noa Put]

Was waiting for this and it does look somewhat disappointing, it does improve a bit over the gh3 but the noise is still pretty obvious.

GH4 Low Light Shootout Vs GH3 Vs 5DMK3 on Vimeo

[Joe Ogiba]

Panasonic Lumix GH4: video sample 4K - YouTube

[John Chalmers]

Here is a link to Andrew Reid's lowlight test of the GH4 vs. GH3 & 5D Mark III raw. Check the video on Vimeo then down load the original MOV. file and watch it using VLC player and see if there is much of a difference!

https://vimeo.com/90981412#at=0

[Noa Put]

He graded the footage and I don't understand why, I"d rather would see it compared straight out of the camera. one thing he mentions makes sense and that is when you downscale from 4k to 1080p the noise becomes smaller which can explain why once you apply neatvideo to it it looks very clean.

[John Chalmers]

@Noa Put, you are correct, I just noticed the grain has been cleaned up compared to the 1st time I saw it on his web site. All three cameras had noise with naturally the 5D having less, with the GH4 being better that the GH3, the original downloaded files were a lot better viewed on VLC than what was displayed on Vimeo at the time. I notice the technical information under the video, still states "No noise reduction applied" but it has definitely been cleaned up from the 1st upload.

[Mark Donnell]

Several questions, and I realize that we may not yet have the answers : 1) why would the GH4 record 4K video at only 100 Bps while recording 1080p video at 200 Bps ? 2) the recording formats listed in the specs are MOV, MP4 and MPEG-4 avchd. I thought MOV was a container, not a codec. What type of video is in the MOV that is being recorded at either 100 or 200 Bps ? The description also states that video recording to memory cards is always 4:2:0, so does this mean that to get 4:2:2 video you have to go out via the micro HDMI to an external recorder ?

[Phil Lee]

Hi

The 200Mbps is all Intra only on 1080P and not 4K, this is pretty easy for the processor to encode as each frame is standalone. Essentially we end up with 60 Jpeg images a second compressed to around 420KBytes in size.

The 100Mbps top rate in 4K and option for 1080P is long GOP, this means the processor needs to process 15 or 30 frames as a group, finding differences between each frame then encoding these differences. Remember this is done in real time, and with 4K there is only so much the processor can handle in terms of data in real-time at those resolutions. It probably can't generate more than 100Mbps of data in real-time. I doubt this limit in long GOP applies to 1080P, but throwing more than 100Mbps at long GOP at HD resolutions probably doesn't yield much if any improvement.

Yes MOV, MP4 and AVCHD are containers or standards, for example AVCHD describes the container and the maximum resolutions/bit-rate, with MOV and MP4 having no limits.

Internal recording is indeed 8bit 4.2.0, most likely to avoid this camera being too good which might take sales away from Panasonic's pro broadcast range, so to record 4.2.2 at 10bit would require an external recorder, in which case you need the GH4 brick added to it (not compulsory but this provides more robust connections for HDMI and SDI outputs) which is pretty costly, and I suspect helps Panasonic insure against losing money from lower sales of its pro range of video cameras.

Regards

Phil

[Joe Ogiba]

Panasonic GH4 C4K to 2K 10-bit Pro Res 444 from Rarevision - improves luminance on Vimeo

[Evan Donn]

I don't see much reason to get the brick unless you specifically need the quad-sdi output. Add Atomos' small Ninja Star to a GH4 and you can have 10bit 422 HD for $300 + media costs without adding much bulk or complication to the whole system. The Shogun will step that up to 4k and give you XLR audio, a calibrated 1080p monitor, and scopes for about the same price as panasonic's box alone. If you're worried about the mini-hdmi connection on the camera there are options like the LockPort or JerkStopper that can protect the connector.

[Michael Bishop]

This GH4 video was uploaded to Vimeo a few hours ago.

Aline au parc Montsouris avec le GH4 on Vimeo

[Noa Put]

A very informative review and yet again confusing info about the display as he says it doesn't disappears like on the gh3, guess I will have to buy one to know for sure :)

Panasonic GH4 vs. GH3 [4K/1080 tests: Moire, Rolling Shutter, Crop Factor, High ISO, Slow Motion] - YouTube

How to set up your new Panasonic GH4 for Filmmaking - YouTube

[David Heath]

Originally Posted by Mark Donnell

Several questions, and I realize that we may not yet have the answers : 1) why would the GH4 record 4K video at only 100 Bps while recording 1080p video at 200 Bps ?

As Phil says, the big difference is that for 4K/100Mbs it's long-GOP, for 1080p/200Mbs it's I-frame only - so simple numeric comparisons don't mean very much. But as a general rule *with all else equal* (normally it isn't :-) ) long-GOP will give equivalent quality to I-frame only with about half to a third the datarate.

Unlike Phil, I suspect the reasons are more mundane than sheer technical. Design a camera and on the one hand you want specs that will give you best quality - on the other realism has to be there to keep costs down such it's viable. As far as codecs go, then you want a high bitrate for quality - but low such that slower (and cheaper) memory can be used problem free, and you don't need as many GB.

In this case, whilst 200Mbs sustained recording is high for consumer memory, they may have reckoned that anyone who wants I-frame only will be prepared for the consequences of 200Mbs. But for 4K, an I-frame only mode would stretch even pro standard (and priced) memory in terms of bitrate to be worthwhile, and not be worth the issues in what is after all, primarily a stills camera.

So go to long-GOP, when 100 Mbs becomes a very good compromise between quality, cost and convenience.

2) the recording formats listed in the specs are MOV, MP4 and MPEG-4 avchd. I thought MOV was a container, not a codec. What type of video is in the MOV that is being recorded at either 100 or 200 Bps ?

I understand the codec is based on H264, with (as you say) it being able to be put into mp4 or mov containers.

The description also states that video recording to memory cards is always 4:2:0, so does this mean that to get 4:2:2 video you have to go out via the micro HDMI to an external recorder ?

I sometimes wish that all talk of 4:2:0 and 4:2:2 could be wiped from history. Go back to the advent of DV based formats and NTSC (which were 4:1:1), whilst at the same time such as NTSC DVD and transmission were 4:2:0. And since we were talking of standard definition and interlace, it is quite true *THEN* that origination in 4:2:2 made a big difference.

Move forward to High Definition and progressive and 4:2:2 becomes less significant, move to 4K and that's even more the case, certainly unless you're talking about very, very big budget equipment indeed. For a camera of the type of the GH4, any difference between 4:2:2/4:2:0 recording is likely to be insignificant compared to sensor/lens/front end factors.

Unfortunately, 4:2:2/4:2:0 is a much simpler concept, and people well remember the Standard Definition /interlace days (when it was a very valid point) and still give it far more emphasis than it remotely deserves as far as 4k is concerned.

[Willard Hill]

Page 25 of the hard copy manual addresses the disappearing display . "If no operation is performed, part of the information on the screen will gradually become darker and will no longer be displayed after approximately one minute has passed. Pressing the [Disp.] button or touching the monitor will make the display reappear. This operation is to preven screen burn-in and is not a malfunction.

The display on my GH4 dims after about ten seconds and partially disappears after about one minute. This is where I was confused and said that the display disappears. Much of it does, but a record indicator, length of clip recorded, audio meters, time code,and remaining time left on card are continuously displayed in a dimmed down fashion, but here is the confusing part, What I just said is true as long as the camera is actually recording. If it is left in standby mode, in time the information will completely disappear.

I have my GH3 running as I am writing and after a time all information disappears except for the record light, length of clip recorded indicator, and remaining time, so the GH4 is improved to the extent that the audio meters are always visible while recording as is an exposure indicator.

At any rate the above is true with my individual cameras and how they are configured.

[Ron Fabienke]

I've noticed on my GH3 that turning the manual focus ring at all in run and gun, also brings back the disappearing information, in addition to the other tricks such as a finger passed close to the the EVF.

[Mark Williams]

This was my first project with my new Panasonic GH4 camera. I have a bit of a learning curve ahead of me as my previous experience was only with camcorders. Lenses used were the Panasonic 14-45mm, 45-175mm and Olympus 60mm macro. Other equipment included the Benro S6 tripod and Glideshot jib.
Shot in standard and cine-v all 0s. ISO 800 and 1600.

Falls on Falls Creek on Vimeo